Publications by authors named "Zijing Chen"

45 Publications

Comparative Transcriptome Analysis of Two Contrasting Chinese Cabbage ( L.) Genotypes Reveals That Ion Homeostasis Is a Crucial Biological Pathway Involved in the Rapid Adaptive Response to Salt Stress.

Front Plant Sci 2021 14;12:683891. Epub 2021 Jun 14.

College of Horticulture Science and Engineering, Shandong Agricultural University, Tai'an, China.

Salt is the most important limiting factor in plant yield and quality. Different Chinese cabbage cultivars appeared different salt tolerances, but there are few studies attempting to elucidate the mechanism underlying this phenomenon. In this study, 100 mmol L NaCl was found to be the most suitable treatment concentration according to a sprouting bag test of 39 Chinese cabbage cultivars, and through comprehensive comparison and analysis, the relative values of fresh weight and electrolyte leakage in leaves proved to be convenient indicators for the identification of salt tolerance in Chinese cabbage. We analyzed the physiological responses of Qinghua45 (salt-tolerant) and Biyuchunhua (salt-sensitive) in terms of the growth indexes, ion homeostasis and Photosynthesis, the results indicated that Qinghua45 could ensure osmotic regulation, ion homeostasis and photosynthesis under salt stress. Next, we compared the transcriptome dynamics of the two cultivars. Overall, 2,859 differentially expressed genes (DEGs) were identified, and the number of DEGs in Qinghua45 was significantly less than that in Biyuchunhua. VDAC promoted the release of Ca, which indirectly promoted the transport of Na to vacuoles through the SOS pathway. Cation/H (+) antiporter 17 and V-H + -ATPase improve the exchange of Na and H and maintain Na in the vacuoles, thereby reducing the injury affected by salt stress. Increases in galactinol synthase and soluble protein synthesis helped relieve osmotic stress caused by salt, together, they regulated the Na content and chlorophyll biosynthesis of the plant and enabled the plant to adapt to salt stress over time.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3389/fpls.2021.683891DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8236865PMC
June 2021

Root morphology ion absorption and antioxidative defense system of two Chinese cabbage cultivars (Brassica rapa L.) reveal the different adaptation mechanisms to salt and alkali stress.

Protoplasma 2021 Jun 18. Epub 2021 Jun 18.

College of Horticulture Science and Engineering, Shandong Agricultural University, Tai'an 271018, People's Republic of China.

Salt stress and alkali stress are major factors that affect the growth and production of Chinese cabbage. To explore their tolerant mechanism to salt and alkali stress, three salinity levels (0, 50, 100 mmol/L NaCl) and three different pH levels (pH6.5, pH7.5, pH8.5) were interactively applied on Qinghua (salt-tolerant-alkali-sensitive) and Biyu (salt-sensitive-alkali-tolerant) cultivars; the root morphology, ion content and antioxidant enzymes were determined. The results showed that the root morphology and root water content of Qinghua under SpH and SpH were seriously affected, and the content of HO and MDA increased by 143%, 190% and 234%, 294%, respectively, compared with SpH; when Biyu was under SpH and SpH stress, the content of HO and MDA increase to 152%, 208% and to 240%, 263%, respectively, but the activities and genes expression of SOD, POD, CAT, AAO, APX, DHAR and MDHAR did not change. The root and the contents of HO and MDA were not affected when Qinghua was treated with salt and Biyu was treated with alkali, but the activities of the antioxidant enzymes increased to 150-200%, and their relative expression was overexpressed and 2.5-3.5-fold of the SpH6.5. The increase of Na in Qinghua was limited under salt stress, Mg in Biyu increased significantly under alkali stress. These all indicated that the adaptability of roots could reflect the degree of tolerance; Chinese cabbage with high salt and alkali tolerance enhanced the regulation of their absorption of ions and increased the relative expression and activities of related antioxidant enzymes.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1007/s00709-021-01675-5DOI Listing
June 2021

Mechanism of genome instability mediated by human DNA polymerase mu misincorporation.

Nat Commun 2021 06 18;12(1):3759. Epub 2021 Jun 18.

Institute of Biophysics, College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang, China.

Pol μ is capable of performing gap-filling repair synthesis in the nonhomologous end joining (NHEJ) pathway. Together with DNA ligase, misincorporation of dGTP opposite the templating T by Pol μ results in a promutagenic T:G mispair, leading to genomic instability. Here, crystal structures and kinetics of Pol μ substituting dGTP for dATP on gapped DNA substrates containing templating T were determined and compared. Pol μ is highly mutagenic on a 2-nt gapped DNA substrate, with T:dGTP base pairing at the 3' end of the gap. Two residues (Lys438 and Gln441) interact with T:dGTP and fine tune the active site microenvironments. The in-crystal misincorporation reaction of Pol μ revealed an unexpected second dGTP in the active site, suggesting its potential mutagenic role among human X family polymerases in NHEJ.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1038/s41467-021-24096-7DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8213813PMC
June 2021

Conserved modules required for TRP function .

J Neurosci 2021 Jun 7. Epub 2021 Jun 7.

Department of Molecular, Cellular, and Developmental Biology and the Neuroscience Research Institute, University of California, Santa Barbara, Santa Barbara, CA 93106, USA

TRP channels are broadly required in animals for sensory physiology. To provide insights into regulatory mechanisms, the structures of many TRPs have been solved. This has led to new models, some of which have been tested Here, using the classical TRP required for visual transduction, we uncovered structural requirements for channel function in photoreceptor cells. Using a combination of molecular genetics, field recordings, protein expression analysis, and molecular modeling, we interrogated roles for the S4-S5 linker and the TRP domain, and revealed mutations in the S4-S5 linker that impair channel opening or closing. We also uncovered differential requirements for the two highly conserved motifs in the TRP domain for activation and protein stability. By performing genetic complementation, we found an intra-subunit interaction between the S4-S5 linker and the S5 segment that contributes to activation. This analysis highlights key structural requirements for TRP channel opening, closing, folding and for intra-subunit interactions in a native context- photoreceptor cells.The importance of TRP channels for sensory biology and human health has motivated tremendous effort in trying to understand the roles of the structural motifs essential for their activation, inactivation and protein folding. In the current work, we have exploited the unique advantages of the visual system to reveal mechanistic insights into TRP channel function in a native system-photoreceptor cells. Using a combination of electrophysiology (field recordings), cell biology and molecular modeling, we have revealed roles of key motifs for activation, inactivation and protein folding of TRP .
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1523/JNEUROSCI.0200-21.2021DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8265800PMC
June 2021

The Spectral Irradiance, Growth, Photosynthetic Characteristics, Antioxidant System, and Nutritional Status of Green Onion ( L.) Grown Under Different Photo-Selective Nets.

Front Plant Sci 2021 25;12:650471. Epub 2021 Mar 25.

College of Horticulture Science and Engineering, Shandong Agricultural University, Tai'an, China.

The active regulation of the plant growth environment is a common method for optimizing plant yield and quality. In horticulture today, light quality control is carried out using photo-selective nets or membranes to improve the yield and quality of cultivated plants. In the present study, with natural light as the control (CK), we tested different photo-selective nets (white, WN; blue, BN; green, GN; yellow, YN; and red, RN) with 30% shade for characteristics of growth, development, quality, yield, photosynthesis, and chlorophyll fluorescence, considering the antioxidant system, as well as the influence of element absorption and transformation of green onion ( L.) plants at different growth stages. We found that plants under BN and WN have greater height and fresh weight than those of plants under the other nets. Plants under the BN treatment had the highest quality, yield, photosynthetic pigment content, net photosynthetic rate, transpiration rate, and stomatal conductance, whereas the intercellular CO concentration was the highest in plants in the YN treatment. The photosynthesis noon break phenomenon was significantly lower in plants with covered photo-selective nets than in CK plants. NPQ was the highest in the YN treatment, and Fv/Fm, ΦPSII, and qP among the plants in the other treatments were different; from highest to lowest, they were as follows: BN > WN > CK > RN > GN > YN. The active oxygen content of green onion leaves in the BN treatment was significantly lower than that in the other treatments, and their key enzyme activity was significantly increased. BN also improved the absorption and transformation of elements in various organs of green onion.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3389/fpls.2021.650471DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8030602PMC
March 2021

Research progress of fruit color development in apple (Malus domestica Borkh.).

Plant Physiol Biochem 2021 May 4;162:267-279. Epub 2021 Mar 4.

State Key Laboratory of Crop Biology, College of Horticulture Science and Engineering, Shandong Agricultural University, Tai'an, Shandong, 271018, China; Collaborative Innovation Center of Fruit & Vegetable Quality and Efficient Production, Tai'an, Shandong, 271000, China. Electronic address:

Apple (Malus domestica Borkh.) is one of the most widely produced and economically important fruits in temperate regions. Fruit color development in apple is a major focus for both breeders and researchers as consumers associate brightly colored red apples with ripeness and a good flavor. In recent years, great progress has been made in the research of apple fruit color development, but its development mechanism has not been systematic dissected from the aspects of genetics, transcription or environmental factors. Here, we summarize research on the coloration of apple fruit, including the development of important genomic databases to identify important genomic regions and genes, genetic and transcriptional factors that regulate pigment accumulation, environmental factors that affect anthocyanin synthesis, and the current breeding progress of red-skinned and red-fleshed apples. We describe key transcription factors, such as MYB, bHLH, and WD40, which are involved in the regulation of anthocyanin synthesis and fruit color development in apple. We also discuss the regulation of apple color by external environmental factors such as light, temperature, and water. The aim of this review is to provide insights into the molecular mechanisms underlying anthocyanin biosynthesis in apple. This information will provide significant guidance for the breeding of high-quality red-skinned and red-fleshed apple varieties.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.plaphy.2021.02.033DOI Listing
May 2021

MazEF Toxin-Antitoxin System-Mediated DNA Damage Stress Response in .

Front Genet 2021 19;12:632423. Epub 2021 Feb 19.

Institute of Biophysics, College of Life Sciences, Zhejiang University, Hangzhou, China.

shows marked resistance to various types of DNA-damaging agents, including mitomycin C (MMC). A type II toxin-antitoxin (TA) system that responds to DNA damage stress was identified in , comprising the toxin MazF-dr and the antitoxin MazE-dr. The cleavage specificity of MazF-dr, an endoribonuclease, was previously characterized. Here, we further investigated the regulatory role of the MazEF system in the response to DNA damage stress in . The crystal structure of MazF (MazF-dr) was determined at a resolution of 1.3 Å and is the first structure of the toxin of the TA system of . MazF-dr forms a dimer mediated by the presence of interlocked loops. Transcriptional analysis revealed 650 downregulated genes in the wild-type (WT) strain, but not in the mutant strain, which are potentially regulated by MazEF-dr in response to MMC treatment. Some of these genes are involved in membrane trafficking and metal ion transportation. Subsequently, compared with the WT strain, the mutant strain exhibited much lower MMC-induced intracellular iron concentrations, reactive oxygen species (ROS), and protein carbonylation levels. These results provide evidence that MazEF-mediated cell death in might be caused by an increase in ROS accumulation upon DNA damage stress.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3389/fgene.2021.632423DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7933679PMC
February 2021

Response of growth, photosynthetic electron transfer, and chloroplast ultrastructure to different LED light combination in green onion (Allium fistulosum L.).

Physiol Plant 2021 Jul 21;172(3):1662-1672. Epub 2021 Mar 21.

College of Horticulture Science and Engineering, Shandong Agricultural University, Tai'an, 271018, China.

With the rapid development of facility agriculture, it has become popular to study the influences of different light qualities on the growth, material metabolism, and morphology of horticultural crops. Last several years, green onions cultivation models have undergone major changes, and facility cultivation has developed rapidly. To determine the impact of light quality on the green onions, we studied the parameters connected to photosynthesis, incorporating growth, and development, photosynthetic rate (P ), chlorophyll fluorescence, light response curve, photosynthetic electron transfer, and chloroplast ultrastructure. We roundly analyzed the influences of different LED light combination (white: W, white-blue combination 3:1:WB, white-green combination 3:1:WG, white-yellow combination 3:1:WY, and white-red combination 3:1:WR, light intensity: 500 ± 10 μmol photons m s ) on the photosynthetic performance of green onions. The WB light led to better results than those of the WR, WG, and WY. There were significant performance improvements in leaf area, plant height, stem thickness, relative growth rate (RGR), pigment content, photosynthetic capacity, photosynthetic electron transfer efficiency, and chloroplast ultrastructure integrity. In contrast, plants treated with WG and WY were exposed to appreciably blocked light, but they effectively formed a light protection mechanism. The results of this research not only provided insight into the response mechanism of crop photosynthesis to different light qualities, but they also provided a scientific foundation for better planting green onions.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1111/ppl.13381DOI Listing
July 2021

Comparison of the effects of LED light quality combination on growth and nutrient accumulation in green onion (Allium fistulosum L.).

Protoplasma 2021 Jul 7;258(4):753-763. Epub 2021 Jan 7.

College of Horticulture Science and Engineering, Shandong Agricultural University, Taishan District, Tai'an, 271018, People's Republic of China.

The growth and development and metabolism of plants have different physiological responses to different light qualities. To study the influence of light qualities on green onions, the impacts of LED light treatment on the growth and development as well as the nutritional components and flavor substances in green onions were studied under controlled conditions. Leaf area, plant height, dry matter accumulation, Dickson's quality index (DQI), nutritional content, and volatile compounds under different light quality treatments were determined. The results indicated that the white and blue combined light (W/B: 3/1) treatment was the most beneficial to growth and nutrient accumulation and led to higher levels of sulfur compounds in the green onions than the other treatments. This shows that it is possible to control the contents of compounds that affect consumer preferences by adjusting the lighting conditions and to thereby increase the value and quality of seasoning vegetables.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1007/s00709-020-01593-yDOI Listing
July 2021

The APETALA2 transcription factor LsAP2 regulates seed shape in lettuce.

J Exp Bot 2021 03;72(7):2463-2476

Beijing Key Laboratory of Growth and Developmental Regulation for Protected Vegetable Crops, Department of Vegetable Science, College of Horticulture, China Agricultural University, Beijing, China.

Seeds are major vehicles of propagation and dispersal in plants. A number of transcription factors, including APETALA2 (AP2), play crucial roles during the seed development process in various plant species. However, genes essential for seed development and the regulatory networks that operate during seed development remain unclear in lettuce. Here, we identified a lettuce AP2 (LsAP2) gene that was highly expressed during the early stages of seed development. LsAP2 knockout plants obtained by the CRISPR/Cas9 system were used to explore the biological function of LsAP2. Compared with the wild type, the seeds of Lsap2 mutant plants were longer and narrower, and developed an extended tip at the seed top. After further investigating the structural characteristics of the seeds of Lsap2 mutant plants, we proposed a new function of LsAP2 in seed dispersal. Moreover, we identified several interactors of LsAP2. Our results showed that LsAP2 directly interacted with the lettuce homolog of BREVIPEDICELLUS (LsBP) and promoted the expression of LsBP. Transcriptome analysis revealed that LsAP2 might also be involved in brassinosteroid biosynthesis and signaling pathways. Taken together, our data indicate that LsAP2 has a significant function in regulating seed shape in lettuce.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1093/jxb/eraa592DOI Listing
March 2021

Calmodulin binds to Drosophila TRP with an unexpected mode.

Structure 2021 04 15;29(4):330-344.e4. Epub 2020 Dec 15.

Shenzhen Key Laboratory for Neuronal Structural Biology, Biomedical Research Institute, Shenzhen Peking University-The Hong Kong University of Science and Technology Medical Center, Shenzhen 518036, China; Greater Bay Biomedical Innocenter, Shenzhen Bay Laboratory, Shenzhen 518055, China; Division of Life Science, State Key Laboratory of Molecular Neuroscience, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China. Electronic address:

Drosophila TRP is a calcium-permeable cation channel essential for fly visual signal transduction. During phototransduction, Ca mediates both positive and negative feedback regulation on TRP channel activity, possibly via binding to calmodulin (CaM). However, the molecular mechanism underlying Ca modulated CaM/TRP interaction is poorly understood. Here, we discover an unexpected, Ca-dependent binding mode between CaM and TRP. The TRP tail contains two CaM binding sites (CBS1 and CBS2) separated by an ∼70-residue linker. CBS1 binds to the CaM N-lobe and CBS2 recognizes the CaM C-lobe. Structural studies reveal the lobe-specific binding of CaM to CBS1&2. Mutations introduced in both CBS1 and CBS2 eliminated CaM binding in full-length TRP, but surprisingly had no effect on the response to light under physiological conditions, suggesting alternative mechanisms governing Ca-mediated feedback on the channel activity. Finally, we discover that TRPC4, the closest mammalian paralog of Drosophila TRP, adopts a similar CaM binding mode.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.str.2020.11.016DOI Listing
April 2021

Non-xenogeneic expansion and definitive endoderm differentiation of human pluripotent stem cells in an automated bioreactor.

Biotechnol Bioeng 2021 02 16;118(2):979-991. Epub 2020 Dec 16.

Department of Chemical and Biological Engineering, Tufts University, Medford, Massachusetts, USA.

Scalable processes are requisite for the robust biomanufacturing of human pluripotent stem cell (hPSC)-derived therapeutics. Toward this end, we demonstrate the xeno-free expansion and directed differentiation of human embryonic and induced pluripotent stem cells to definitive endoderm (DE) in a controlled stirred suspension bioreactor (SSB). Based on previous work on converting hPSCs to insulin-producing progeny, differentiation of two hPSC lines was optimized in planar cultures yielding up to 87% FOXA2 /SOX17 cells. Next, hPSCs were propagated in an SSB with controlled pH and dissolved oxygen. Cultures displayed a 10- to 12-fold increase in cell number over 5-6 days with the maintenance of pluripotency (>85% OCT4 ) and viability (>85%). For differentiation, SSB cultures yielded up to 89% FOXA2 /SOX17 cells or ~ 8 DE cells per seeded hPSC. Specification to DE cell fate was consistently more efficient in the bioreactor compared to planar cultures. Hence, a tunable strategy is established that is suitable for the xeno-free manufacturing of DE cells from different hPSC lines in scalable SSBs. This study advances bioprocess development for producing a wide gamut of human DE cell-derived therapeutics.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/bit.27629DOI Listing
February 2021

Structural features and functional implications of proteins enabling the robustness of .

Comput Struct Biotechnol J 2020 7;18:2810-2817. Epub 2020 Oct 7.

Institute of Biophysics, College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang, China.

can survive under extreme conditions, including high doses of DNA damaging agents and ionizing radiation, desiccation, and oxidative stress. Both the efficient cellular DNA repair machinery and antioxidation systems contribute to the extreme resistance of this bacterium, making it an ideal organism for studying the cellular mechanisms of environmental adaptation. The number of stress-related proteins identified in this bacterium has mushroomed in the past two decades. The newly identified proteins reveal both commonalities and diversity of structure, mechanism, and function, which impact a wide range of cellular functions. Here, we review the unique and general structural features of these proteins and discuss how these studies improve our understanding of the environmental stress adaptation mechanisms of .
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.csbj.2020.09.036DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7575645PMC
October 2020

HEAT SHOCK FACTOR A8a Modulates Flavonoid Synthesis and Drought Tolerance.

Plant Physiol 2020 11 21;184(3):1273-1290. Epub 2020 Sep 21.

State Key Laboratory of Crop Biology, College of Horticulture Sciences, Shandong Agricultural University, 271018 Tai'an, Shandong, China

Drought is an important environmental factor affecting the growth and production of agricultural crops and fruits worldwide, including apple (). Heat shock factors (HSFs) have well-documented functions in stress responses, but their roles in flavonoid synthesis and the flavonoid-mediated drought response mechanism remain elusive. In this study, we demonstrated that a drought-responsive HSF, designated MdHSFA8a, promotes the accumulation of flavonoids, scavenging of reactive oxygen species, and plant survival under drought conditions. A chaperone, HEAT SHOCK PROTEIN90 (HSP90), interacted with MdHSFA8a to inhibit its binding activity and transcriptional activation. However, under drought stress, the MdHSP90-MdHSFA8a complex dissociated and the released MdHSFA8a further interacted with the APETALA2/ETHYLENE RESPONSIVE FACTOR family transcription factor RELATED TO AP2.12 to activate downstream gene activity. In addition, we demonstrated that MdHSFA8a participates in abscisic acid-induced stomatal closure and promotes the expression of abscisic acid signaling-related genes. Collectively, these findings provide insight into the mechanism by which stress-inducible MdHSFA8a modulates flavonoid synthesis to regulate drought tolerance.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1104/pp.20.01106DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7608180PMC
November 2020

Frailty in Chronic Obstructive Pulmonary Disease and Risk of Exacerbations and Hospitalizations.

Int J Chron Obstruct Pulmon Dis 2020 11;15:1967-1976. Epub 2020 Aug 11.

Department of Health Services Research and Development, Veterans Affairs Puget Sound Health Care System, Seattle, WA, USA.

Background: Frailty is a complex clinical syndrome associated with vulnerability to adverse health outcomes. While frailty is thought to be common in chronic obstructive pulmonary disease (COPD), the relationship between frailty and COPD-related outcomes such as risk of acute exacerbations of COPD (AE-COPD) and hospitalizations is unclear.

Purpose: To examine the association between physical frailty and risk of acute exacerbations, hospitalizations, and mortality in patients with COPD.

Methods: A longitudinal analysis of data from a cohort of 280 participants was performed. Baseline frailty measures included exhaustion, weakness, low activity, slowness, and undernutrition. Outcome measures included AE-COPD, hospitalizations, and mortality over 2 years. Negative binomial regression and Cox proportional hazard modeling were used.

Results: Sixty-two percent of the study population met criteria for pre-frail and 23% were frail. In adjusted analyses, the frailty syndrome was not associated with COPD exacerbations. However, among the individual components of the frailty syndrome, weakness measured by handgrip strength was associated with increased risk of COPD exacerbations (IRR 1.46, 95% CI 1.09-1.97). The frailty phenotype was not associated with all-cause hospitalizations but was associated with increased risk of non-COPD-related hospitalizations.

Conclusion: This longitudinal cohort study shows that a high proportion of patients with COPD are pre-frail or frail. The frailty phenotype was associated with an increased risk of non-COPD hospitalizations but not with all-cause hospitalizations or COPD exacerbations. Among the individual frailty components, low handgrip strength was associated with increased risk of COPD exacerbations over a 2-year period. Measuring handgrip strength may identify COPD patients who could benefit from programs to reduce COPD exacerbations.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.2147/COPD.S245505DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7429100PMC
June 2021

A Family of Auxiliary Subunits of the TRP Cation Channel Encoded by the Complex Locus.

Genetics 2020 07 20;215(3):713-728. Epub 2020 May 20.

Department of Molecular, Cellular, and Developmental Biology and the Neuroscience Research Institute, University of California, Santa Barbara, California 93106

TRP channels function in many types of sensory receptor cells. Despite extensive analyses, an open question is whether there exists a family of auxiliary subunits, which could influence localization, trafficking, and function of TRP channels. Here, using , we reveal a previously unknown TRP interacting protein, INAF-C, which is expressed exclusively in the ultraviolet-sensing R7 photoreceptor cells. INAF-C is encoded by an unusual locus comprised of four distinct coding regions, which give rise to four unique single-transmembrane-containing proteins. With the exception of INAF-B, roles for the other INAF proteins were unknown. We found that both INAF-B and INAF-C are required for TRP stability and localization in R7 cells. Conversely, loss of just INAF-B greatly reduced TRP from other types of photoreceptor cells, but not R7. The requirements for TRP and INAF are reciprocal, since loss of TRP decreased the concentrations of both INAF-B and INAF-C. INAF-A, which is not normally expressed in photoreceptor cells, can functionally substitute for INAF-B, indicating that it is a third TRP auxiliary protein. Reminiscent of the structural requirements between K channels and KCNE auxiliary subunits, the codependencies of TRP and INAF depended on several transmembrane domains (TMDs) in TRP, and the TMD and the C-terminus of INAF-B. Our studies support a model in which the locus encodes a family of at least three TRP auxiliary subunits.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1534/genetics.120.303268DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7337069PMC
July 2020

Effect of a mist culture system on photosynthesis and nitrogen metabolism in ginger.

Protoplasma 2020 Sep 14;257(5):1359-1371. Epub 2020 May 14.

College of Horticulture Science and Engineering, Shandong Agricultural University, Tai'an, 271018, Shandong, China.

To evaluate the transition from traditional shading cultivation to mist cultivation, a field experiment was carried out. The results demonstrated that compared with traditional shading, the mist treatment significantly reduced leaf temperature. Likewise, the higher transpiration rate also contributes to reducing leaf temperature and protects ginger from heat stress in summer. Moreover, a higher instantaneous efficiency of water use suggested that water lost via transpiration was beneficial under a mist culture system. The higher instantaneous efficiency of water use in the mist treatment was caused mainly by the higher net photosynthetic rate, which is further reflected by the higher rhizome yield of ginger under the mist culture system. Instead of lowering the temperature by lowering photon flux density, mist treatment does not seriously reduce the photon flux density while reducing the temperature of the blade. Hence, the net photosynthetic rate in the shading treatment is significantly lower than that in the mist treatment, although the maximal quantum yield of photosystem II and the actual photochemical efficiency of photosystem II in ginger in the shading treatment were significantly higher than those in the mist treatment. Lower superoxide anion, hydrogen peroxide, and malondialdehyde contents were also found after mist treatment. Lower ammonium avoids the potential risk of ammonium toxicity and is based on higher nitrate reductase, glutamine synthetase, and glutamate synthase activity but lower glutamate dehydrogenase activity. Therefore, the mist cultivation system improved the physiological characteristics and yields of ginger and can be suggested as an alternative, sustainable, and cleaner cultivation measure.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1007/s00709-020-01511-2DOI Listing
September 2020

Intermolecular π-π Conjugation Self-Assembly to Stabilize Surface Passivation of Highly Efficient Perovskite Solar Cells.

Adv Mater 2020 Jun 30;32(23):e1907396. Epub 2020 Apr 30.

Key Laboratory for Renewable Energy, Chinese Academy of Sciences (CAS), Beijing, 100190, P. R. China.

Surface passivation is an effective approach to eliminate defects and thus to achieve efficient perovskite solar cells, while the stability of the passivation effect is a new concern for device stability engineering. Herein, tribenzylphosphine oxide (TBPO) is introduced to stably passivate the perovskite surface. A high efficiency exceeding 22%, with steady-state efficiency of 21.6%, is achieved, which is among the highest performances for TiO planar cells, and the hysteresis is significantly suppressed. Further density functional theory (DFT) calculation reveals that the surface molecule superstructure induced by TBPO intermolecular π-π conjugation, such as the periodic interconnected structure, results in a high stability of TBPO-perovskite coordination and passivation. The passivated cell exhibits significantly improved stability, with sustaining 92% of initial efficiency after 250 h maximum-power-point tracking. Therefore, the construction of a stabilized surface passivation in this work represents great progress in the stability engineering of perovskite solar cells.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/adma.201907396DOI Listing
June 2020

Rapid Release of Ca from Endoplasmic Reticulum Mediated by Na/Ca Exchange.

J Neurosci 2020 04 10;40(16):3152-3164. Epub 2020 Mar 10.

Department of Physiology Development and Neuroscience, Cambridge University, Cambridge, CB2 3EG, United Kingdom,

Phototransduction in is mediated by phospholipase C (PLC) and Ca-permeable TRP channels, but the function of endoplasmic reticulum (ER) Ca stores in this important model for Ca signaling remains obscure. We therefore expressed a low affinity Ca indicator (ER-GCaMP6-150) in the ER, and measured its fluorescence both in dissociated ommatidia and from intact flies of both sexes. Blue excitation light induced a rapid (tau ∼0.8 s), PLC-dependent decrease in fluorescence, representing depletion of ER Ca stores, followed by a slower decay, typically reaching ∼50% of initial dark-adapted levels, with significant depletion occurring under natural levels of illumination. The ER stores refilled in the dark within 100-200 s. Both rapid and slow store depletion were largely unaffected in InsP receptor mutants, but were much reduced in mutants. Strikingly, rapid (but not slow) depletion of ER stores was blocked by removing external Na and in mutants of the Na/Ca exchanger, CalX, which we immuno-localized to ER membranes in addition to its established localization in the plasma membrane. Conversely, overexpression of greatly enhanced rapid depletion. These results indicate that rapid store depletion is mediated by Na/Ca exchange across the ER membrane induced by Na influx via the light-sensitive channels. Although too slow to be involved in channel activation, this Na/Ca exchange-dependent release explains the decades-old observation of a light-induced rise in cytosolic Ca in photoreceptors exposed to Ca-free solutions. Phototransduction in is mediated by phospholipase C, which activates TRP cation channels by an unknown mechanism. Despite much speculation, it is unknown whether endoplasmic reticulum (ER) Ca stores play any role. We therefore engineered flies expressing a genetically encoded Ca indicator in the photoreceptor ER. Although NCX Na/Ca exchangers are classically believed to operate only at the plasma membrane, we demonstrate a rapid light-induced depletion of ER Ca stores mediated by Na/Ca exchange across the ER membrane. This NCX-dependent release was too slow to be involved in channel activation, but explains the decades-old observation of a light-induced rise in cytosolic Ca in photoreceptors bathed in Ca-free solutions.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1523/JNEUROSCI.2675-19.2020DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7159893PMC
April 2020

Photosynthetic characteristics and chloroplast ultrastructure of welsh onion (Allium fistulosum L.) grown under different LED wavelengths.

BMC Plant Biol 2020 Feb 17;20(1):78. Epub 2020 Feb 17.

College of Horticulture Science and Engineering, Shandong Agricultural University, Tai'an, China.

Background: The optimized illumination of plants using light-emitting diodes (LEDs) is beneficial to their photosynthetic performance, and in recent years, LEDs have been widely used in horticultural facilities. However, there are significant differences in the responses of different crops to different wavelengths of light. Thus, the influence of artificial light on photosynthesis requires further investigation to provide theoretical guidelines for the light environments used in industrial crop production. In this study, we tested the effects of different LEDs (white, W; blue, B; green, G; yellow, Y; and red, R) with the same photon flux density (300 μmol/m·s) on the growth, development, photosynthesis, chlorophyll fluorescence characteristics, leaf structure, and chloroplast ultrastructure of Welsh onion (Allium fistulosum L.) plants.

Results: Plants in the W and B treatments had significantly higher height, leaf area, and fresh weight than those in the other treatments. The photosynthetic pigment content and net photosynthetic rate (P) in the W treatment were significantly higher than those in the monochromatic light treatments, the transpiration rate (E) and stomatal conductance (G) were the highest in the B treatment, and the intercellular CO concentration (C) was the highest in the Y treatment. The non-photochemical quenching coefficient (NPQ) was the highest in the Y treatment, but the other chlorophyll fluorescence characteristics differed among treatments in the following order: W > B > R > G > Y. This includes the maximum photochemical efficiency of photosystem II (PSII) under dark adaptation (Fv/Fm), maximum photochemical efficiency of PSII under light adaptation (Fv'/Fm'), photochemical quenching coefficient (qP), actual photochemical efficiency (ΦPSII), and apparent electron transport rate (ETR). Finally, the leaf structure and chloroplast ultrastructure showed the most complete development in the B treatment.

Conclusions: White and blue light significantly improved the photosynthetic efficiency of Welsh onions, whereas yellow light reduced the photosynthetic efficiency.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1186/s12870-020-2282-0DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7027053PMC
February 2020

Nursing Research Priorities in Critical Care, Pulmonary, and Sleep: International Delphi Survey of Nurses, Patients, and Caregivers.

Ann Am Thorac Soc 2020 01;17(1):1-10

The objective of this workshop was to determine current nursing research priorities in critical care, adult pulmonary, and sleep conditions through input from consumer (patient, family, and formal and informal caregivers) and nursing experts around the world. Working groups composed of nurses and patients selected potential research priorities based on patient insight and a literature review of patient-reported outcomes, patient-reported experiences, and processes and clinical outcomes in the focal areas. A Delphi consensus approach, using a qualitative survey method to elicit expert opinion from nurses and consumers was conducted. Two rounds of online surveys available in English, Spanish, and Chinese were completed. A 75% or greater threshold for endorsement (combined responses from nursing and consumer participants) was determined to retain survey items. A total of 837 participants (649 nurses and 188 patients, family, and/or caregivers) from 45 countries responded. Survey data were analyzed and nursing research priorities that comprise 23 critical care, 45 adult pulmonary, and 16 sleep items were identified. This project was successful in engaging a wide variety of nursing and consumer experts, applying a patient-reported outcome/patient-reported experience framework for organizing and understanding research priorities. The project outcome was a research agenda to inform, guide, and aid nurse scientists, educators, and providers, and to advise agencies that provide research and program funding in these fields.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1513/AnnalsATS.201909-705STDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6944344PMC
January 2020

Comparative analysis of the chemical composition and water permeability of the cuticular wax barrier in Welsh onion (Allium fistulosum L.).

Protoplasma 2020 May 17;257(3):833-840. Epub 2019 Dec 17.

College of Horticulture Science and Engineering, Shandong Agricultural University, Tai'an, 271018, People's Republic of China.

Cuticular wax is a hydrophobic barrier between the plant surface and the environment that effectively reduces the loss of water. The surface of Welsh onion leaves is covered with wax. To explain the relationship between wax composition and water loss, we conducted this experiment. The water permeability and wax composition of leaves were determined by chemical and GC-MS methods. We performed a comparative analysis of the differences between the two cultivars and analyzed the relationship between water permeability and waxy components. Overall, the permeability to water was higher in 'Zhangqiu' than in 'Tenko'. The wax amount of 'Tenko' was 1.28-fold higher than that of 'Zhangqiu' and was primarily explained by the much larger amounts of ketones and alcohols in the former. Among the waxy components, C29 ketones were most abundant. There were substantial discrepancies in wax composition, total wax content, and water permeability between the two cultivars. The main reason for the discrepancy in water permeability may be the significantly lower aliphatic fraction in 'Zhangqiu' than in 'Tenko'. This study makes a vital contribution to drought resistance research on allium plants.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1007/s00709-019-01470-3DOI Listing
May 2020

Four Decades After the Discovery of Regenerating Islet-Derived (Reg) Proteins: Current Understanding and Challenges.

Front Cell Dev Biol 2019 22;7:235. Epub 2019 Oct 22.

Department of Chemical and Biological Engineering, Tufts University, Medford, MA, United States.

Regenerating islet-derived (Reg) proteins have emerged as multifunctional agents with pro-proliferative, anti-apoptotic, differentiation-inducing and bactericidal properties. Over the last 40 years since first discovered, Reg proteins have been implicated in a gamut of maladies including diabetes, various types of cancer of the digestive tract, and Alzheimer disease. Surprisingly though, a consensus is still absent on the regulation of their expression, and molecular underpinning of their function. Here, we provide a critical appraisal of recent findings in the field of Reg protein biology. Specifically, the structural characteristics are reviewed particularly in connection with established or purported functions of different members of the Reg family. Moreover, Reg expression patterns in different tissues both under normal and pathophysiological conditions are summarized. Putative receptors and cascades reported to relay Reg signaling inciting cellular responses are presented aiming at a better appreciation of the biological activities of the distinct Reg moieties. Challenges are also discussed that have hampered thus far the rapid progress in this field such as the use of non-standard nomenclature for Reg molecules among various research groups, the existence of multiple Reg members with significant degree of homology and possibly compensatory modes of action, and the need for common assays with robust readouts of Reg activity. Coordinated research is warranted going forward, given that several research groups have independently linked Reg proteins to diseased states and raised the possibility that these biomolecules can serve as therapeutic targets and biomarkers.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3389/fcell.2019.00235DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6817481PMC
October 2019

Alleviating effects of silicate, selenium, and microorganism fertilization on lead toxicity in ginger (Zingiber officinale Roscoe).

Plant Physiol Biochem 2019 Dec 28;145:153-163. Epub 2019 Oct 28.

College of Horticulture Science and Engineering, Shandong Agricultural University, PR China; Collaborative Innovation Center of Fruit &, Vegetable Quality and Efficient Production in Shandong, PR China; Key Laboratory of Biology and Genetic Improvement of Horticultural Crops in Huanghuai Region, Ministry of Agriculture and Rural Affairs, PR China; State Key Laboratory of Crop Biology, Shandong Agricultural University, PR China. Electronic address:

The aim of this work was exploring the effects of silicon, selenium, and a microorganism fertilizer on alleviating the effects of lead (Pb) toxicity in ginger. Ginger plants were grown in soil containing 500 mg/kg Pb(NO) without (CK) or with Si, Se, or microorganism fertilizer (T1, T2, T3) as soil conditioners. Morphology indexes, Pb accumulation and distribution rates, and antioxidant enzyme activities were investigated. The Pb transfer and Pb absorption coefficients were calculated, and Pb accumulation in plant organs at various developmental stages were determined. All three soil conditioners alleviated Pb stress in ginger plants. The rhizome fresh weight in T1, T2, and T3 was increased by 96.06, 85.81, and 41.58%, respectively, compared with CK. The accumulation of Pb in organs was lower in all treatments than in CK. The chlorophyll and carotenoid contents in leaves, and root activity, root length, and the tolerance index, were higher in the treatments than in CK. The reactive oxygen species content in ginger leaves and roots was significantly lower in all treatments than in CK. Soil conditioners alleviated the negative effects of Pb stress on ginger plants: Si was the most effective, followed by Se, and then the microorganism fertilizer.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.plaphy.2019.10.027DOI Listing
December 2019

Concise Synthesis of Open-Cage Fullerenes for Oxygen Delivery.

Angew Chem Int Ed Engl 2019 Dec 22;58(49):17690-17694. Epub 2019 Oct 22.

Beijing National Laboratory for Molecular Sciences, Key Laboratory of Bioorganic Chemistry and Molecular Engineering of the Ministry of Education, College of Chemistry and Molecular Engineering, Peking University, Beijing, 100871, China.

Open-cage fullerenes with a 19-membered orifice were prepared in three steps from C . The key step for cage-opening is aniline mediated ring expansion of a fullerene-mixed peroxide with a ketolactone moiety on the orifice. Release of ring strain on the spherical fullerene cage served as the main driving force for the efficient cage-opening sequence. Encapsulation of oxygen could be achieved at room temperature under moderate pressure (50 atm) and the encapsulated oxygen could be released slowly under ambient conditions. The activation energy of the oxygen-releasing process is 18.8 kcal mol and the half-life at 37 °C was 73 min, which makes this open-cage fullerene derivative a potential oxygen-delivery material.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/anie.201911631DOI Listing
December 2019

Succinylome Analysis Reveals the Involvement of Lysine Succinylation in the Extreme Resistance of Deinococcus radiodurans.

Proteomics 2019 10 25;19(20):e1900158. Epub 2019 Sep 25.

Key Laboratory of Chinese Ministry of Agriculture for Nuclear-Agricultural Sciences, Institute of Nuclear-Agricultural Sciences, Zhejiang University, Zhejiang, 310058, China.

Increasing evidence shows that the succinylation of lysine residues mainly regulates enzymes involved in the carbon metabolism pathway, in both prokaryotic and eukaryotic cells. Deinococcus radiodurans is one of the most radioresistant organisms on earth and is famous for its robust resistance. A major goal in the current study of protein succinylation is to explore its function in D. radiodurans. High-resolution LC-MS/MS is used for qualitative proteomics to perform a global succinylation analysis of D. radiodurans and 492 succinylation sites in 270 proteins are identified. These proteins are involved in a variety of biological processes and pathways. It is found that the enzymes involved in nucleic acid binding/processing are enriched in D. radiodurans compared with their previously reported levels in other bacteria. The mutagenesis studies confirm that succinylation regulates the enzymatic activities of species-specific proteins PprI and DdrB, which belong to the radiation-desiccation response regulon. Together, these results provide insight into the role of lysine succinylation in the extreme resistance of D. radiodurans.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/pmic.201900158DOI Listing
October 2019

MicroRNA-7 directly targets in pancreatic cells.

Am J Physiol Cell Physiol 2019 08 5;317(2):C366-C374. Epub 2019 Jun 5.

Department of Chemical and Biological Engineering, Tufts University, Medford, Massachusetts.

Regenerating islet-derived (Reg) proteins, which were first discovered in the pancreas, are associated with increased proliferation, prevention of apoptosis, and enhanced differentiation in normal and disease states, but very little is known about the regulation of their expression. We hypothesized that Reg expression is influenced by microRNAs. Bioinformatic analysis predicted Reg1 to be a target of microRNA-7 (miR-7), which influences pancreatic β-cell function. To this end, we investigated the effects of miR-7 on Reg1 expression in pancreatic acinar and islet β-cells. High levels of Reg1 were noted by immunostaining and Western blotting in acinar cells in contrast to islet cells. A reciprocal expression pattern was observed for miR-7. Overexpression of miR-7 resulted in Reg1 mRNA suppression and reduction of secreted Reg1 protein. Conversely, miR-7 knockdown led to increases in Reg1. Targeting of Reg1 by miR-7 was confirmed via luciferase activity assays. In contrast, miR-7 did not directly repress the human ortholog of Reg1 REG1A as well as REG1B indicating species differences in the regulation of Reg expression. This is the first account of microRNA modulation of any Reg member warranting studies to fill gaps in our knowledge of Reg protein biology, particularly in disease contexts.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1152/ajpcell.00013.2019DOI Listing
August 2019

Assessing the performance of different irrigation systems on lettuce (Lactuca sativa L.) in the greenhouse.

PLoS One 2019 4;14(2):e0209329. Epub 2019 Feb 4.

Department of Vegetable Sciences, Beijing Key Laboratory of Growth and Developmental Regulation for Protected Vegetable Crops, China Agricultural University, Beijing, China.

Lettuce (Lactuca sativa L.) is a very important leafy vegetable in China and is commonly grown using furrow irrigation. In order to improve production efficiency, greenhouse experiments were conducted at Experimental Station, China Agricultural University, Beijing, China using furrow irrigation (FI), micro-sprinkler irrigation (MS), plastic film mulching irrigation (PF) and a combined plastic film mulching-micro-sprinkler irrigation system (PF+MS) to study their effects on soil physical characteristics, water distribution, root morpho-physiological traits, nutrition absorption, lettuce yield and water use efficiency for a spring crop and autumn crop in 2015 (Fig 1). Root length, root surface area, and root density were significantly higher under PF and PF+MS than under FI. Moreover, these traits were higher under MS than under FI but these differences were not significant. The soluble protein, soluble sugar, and Vitamin C content of lettuce decreased in the order PF+MS > PF > MS > FI in both crops. In the spring crop, the biological yield of MS, PF, and PF+MS was 7.22%、36.77%、43.20% higher than FI, respectively. In the spring crop, biological water use efficiency (BWUE) of FI, MS, PF and PF+MS was 20.93, 25.24, 36.81 and 38.54 kg m-3, respectively. The BWUE of MS, PF, and PF+MS was 20.59%, 75.87% and 84.14% higher than FI. Economic water use efficiency (EWUE) of FI, MS, PF and PF+MS was 17.06, 21.31, 31.11 and 32.31 kg m-3, respectively. The EWUE of MS, PF, and PF+MS was 24.91%, 82.36% and 89.39% higher than FI, respectively. The autumn crop achieved a higher WUE than the spring crop. The results suggested that the combined plastic film mulching-micro-sprinkler irrigation was the most suitable irrigation approach for increasing lettuce yield.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0209329PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6361420PMC
October 2019

Genome-wide analysis of MADS-box family genes during flower development in lettuce.

Plant Cell Environ 2019 06 20;42(6):1868-1881. Epub 2019 Feb 20.

Department of Vegetable Sciences, Beijing Key Laboratory of Growth and Developmental Regulation for Protected Vegetable Crops, China Agricultural University, Beijing, 100193, China.

Lettuce (Lactuca sativa L.) is an important leafy vegetable consumed worldwide. Heat-induced bolting and flowering greatly limit lettuce production during the summer. Additionally, MADS-box transcription factors are important for various aspects of plant development and architecture (e.g., flowering and floral patterning). However, there has been no comprehensive study of lettuce MADS-box family genes. In this study, we identified 82 MADS-box family genes in lettuce, including 23 type I genes and 59 type II genes. Transcriptome profiling revealed that LsMADS gene expression patterns differ among the various floral stages and organs. Moreover, heat-responsive cis-elements were detected in the promoter regions of many LsMADS genes. An in situ hybridization assay of 10 homologs of flower-patterning genes and a yeast two-hybrid assay of the encoded proteins revealed that the ABC model is conserved in lettuce. Specifically, the APETALA1 (AP1) homolog in lettuce, LsMADS55, is responsive to heat and is specifically expressed in the inflorescence meristem and pappus bristles. The overexpression of LsMADS55 results in early flowering in Arabidopsis thaliana. Furthermore, we observed that the heat shock factor LsHSFB2A-1 can bind to the LsMADS55 promoter in lettuce. Therefore, a model was proposed for the LsMADS-regulated floral organ specification and heat-induced flowering in lettuce.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1111/pce.13523DOI Listing
June 2019

The proanthocyanidin-specific transcription factor MdMYBPA1 initiates anthocyanin synthesis under low-temperature conditions in red-fleshed apples.

Plant J 2018 10 21;96(1):39-55. Epub 2018 Aug 21.

State Key Laboratory of Crop Biology, Shandong Agricultural University, No. 61 Daizong Road, 271018, Tai'an, Shandong, China.

In plants, flavonoids play critical roles in resistance to biotic and abiotic stresses, and contribute substantially to the quality, flavor, and nutritional quality of many fruit crops. In apple (Malus × domestica), inbreeding has resulted in severe decreases in the genetic diversity and flavonoid content. Over the last decade, we have focused on the genetic improvement of apple using wild red-fleshed apple resources (Malus sieversii f. niedzwetzkyana). Here, we found that the MYB transcription factors (TFs) involved in the synthesis of proanthocyanidins can be classified into TT2 and PA1 types. We characterized a PA1-type MYB transcription factor, MdMYBPA1, from red-fleshed apple and identified its role in flavonoid biosynthesis using overexpression and knockdown-expression transgenes in apple calli. We explored the relationship between TT2- and PA1-type MYB TFs, and found that MdMYB9/11/12 bind the MdMYBPA1 promoter. In addition, MdMYBPA1 responded to low temperature by redirecting the flavonoid biosynthetic pathway from proanthocyanidin to anthocyanin production. In binding analyses, MdbHLH33 directly bound to the low-temperature-responsive (LTR) cis-element of the MdMYBPA1 promoter and promotes its activity. In addition, the calli expressing both MdMYBPA1 and MdbHLH33, which together form a complex, produced more anthocyanin under low temperature. Our findings shed light on the essential roles of PA1-type TFs in the metabolic network of proanthocyanidin and anthocyanin synthesis in plants. Studies on red-fleshed wild apple are beneficial for breeding new apple varieties with high flavonoid contents.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1111/tpj.14013DOI Listing
October 2018
-->