Publications by authors named "Juan Manuel Vilas"

5 Publications

  • Page 1 of 1

Close relationship between the state of the oxygen evolving complex and rice cold stress tolerance.

Plant Sci 2020 Jul 9;296:110488. Epub 2020 Apr 9.

Laboratorio de Fisiología de Estrés Abiótico en Plantas, Unidad de Biotecnología 1, INTECH-CONICET-UNSAM, Chascomús, Argentina. Electronic address:

The results of the present work suggested a relationship between the growth stability and functional/structural parameters associated to the primary photochemistry and oxygen evolving complex (OEC) in tolerant rice plants under suboptimal low temperatures (SLT) stress. This was concluded from the absence of changes in net photosynthetic rate and in fraction of reaction centers to reduce quinone A, and very small changes in P680 efficiency to trap and donate electrons to quinone A and in fraction of active OEC in tolerant plants under cold stress but not in sensitive plants. The SLT stress also induced OEC activity limitations in both genotypes, but in a greater extent in sensitive plants. However, an assay using an artificial electron donor to replace OEC indicated that the P680 capacity to accept electrons was not altered in both genotypes under SLT stress from the beginning of the stress treatment, suggesting that the OEC structure stability is related to rice SLT tolerance to sustain the photosynthesis. This hypothesis was also supported by the fact that tolerant plants but not sensitive plants did not alter the gene expression and protein content of PsbP under SLT stress, an OEC subunit with a role in stabilizing of OEC structure.
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http://dx.doi.org/10.1016/j.plantsci.2020.110488DOI Listing
July 2020

The fungal endophyte Fusarium solani provokes differential effects on the fitness of two Lotus species.

Plant Physiol Biochem 2019 Nov 17;144:100-109. Epub 2019 Sep 17.

Instituto de Investigaciones Biotecnológicas-Instituto Tecnológico de Chascomús (IIB-INTECH), Av. Intendente Marino km 8.2, Chascomús, 7130, Argentina; Instituto de Fisiología y Recursos Genéticos Vegetales-Instituto Nacional de Tecnología Agropecuaria (IFRGV-INTA), Camino 60 cuadras km 5.5, Córdoba, 5119, Argentina. Electronic address:

The interactions established between plants and endophytic fungi span a continuum from beneficial to pathogenic associations. The aim of this work was to isolate potentially beneficial fungal endophytes in the legume Lotus tenuis and explore the mechanisms underlying their effects. One of the nine fungal strains isolated was identified as Fusarium solani and shows the highest phosphate-solubilisation activity, and also grows endophytically in roots of L. japonicus and L. tenuis. Interestingly, fungal invasion enhances plant growth in L. japonicus but provokes a contrasting effect in L. tenuis. These differences were also evidenced when the rate of photosynthesis as well as sugars and K contents were assessed. Our results indicate that the differential responses observed are due to distinct mechanisms deployed during the establishment of the interactions that involve the regulation of photosynthesis, potassium homeostasis, and carbohydrate metabolism. These responses are employed by these plant species to maintain fitness during the endophytic interaction.
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http://dx.doi.org/10.1016/j.plaphy.2019.09.022DOI Listing
November 2019

The increase of photosynthetic carbon assimilation as a mechanism of adaptation to low temperature in Lotus japonicus.

Sci Rep 2019 01 29;9(1):863. Epub 2019 Jan 29.

Instituto de Investigaciones Biotecnológicas-Instituto Tecnológico de Chascomús (IIB-INTECH), UNSAM-CONICET, Buenos Aires, Argentina.

Low temperature is one of the most important factors affecting plant growth, it causes an stress that directly alters the photosynthetic process and leads to photoinhibition when severe enough. In order to address the photosynthetic acclimation response of Lotus japonicus to cold stress, two ecotypes with contrasting tolerance (MG-1 and MG-20) were studied. Their chloroplast responses were addressed after 7 days under low temperature through different strategies. Proteomic analysis showed changes in photosynthetic and carbon metabolism proteins due to stress, but differentially between ecotypes. In the sensitive MG-1 ecotype acclimation seems to be related to energy dissipation in photosystems, while an increase in photosynthetic carbon assimilation as an electron sink, seems to be preponderant in the tolerant MG-20 ecotype. Chloroplast ROS generation was higher under low temperature conditions only in the MG-1 ecotype. These data are consistent with alterations in the thylakoid membranes in the sensitive ecotype. However, the accumulation of starch granules observed in the tolerant MG-20 ecotype indicates the maintenance of sugar metabolism under cold conditions. Altogether, our data suggest that different acclimation strategies and contrasting chloroplast redox imbalance could account for the differential cold stress response of both L. japonicus ecotypes.
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http://dx.doi.org/10.1038/s41598-018-37165-7DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6351645PMC
January 2019

Modulation of plant and bacterial polyamine metabolism during the compatible interaction between tomato and Pseudomonas syringae.

J Plant Physiol 2018 Dec 27;231:281-290. Epub 2018 Sep 27.

Laboratorio de estrés biótico y abiótico en plantas, Instituto de Investigaciones Biotecnológicas-Instituto Tecnológico de Chascomús (IIB-INTECh), Universidad Nacional de San Martín (UNSAM), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Avenida Intendente Marino Km 8.200 CC 164 (7130), Chascomús, Buenos Aires, Argentina. Electronic address:

The polyamines putrescine, spermidine and spermine participate in a variety of cellular processes in all organisms. Many studies have shown that these polycations are important for plant immunity, as well as for the virulence of diverse fungal phytopathogens. However, the polyamines' roles in the pathogenesis of phytopathogenic bacteria have not been thoroughly elucidated to date. To obtain more information on this topic, we assessed the changes in polyamine homeostasis during the infection of tomato plants by Pseudomonas syringae. Our results showed that polyamine biosynthesis and catabolism are activated in both tomato and bacteria during the pathogenic interaction. This activation results in the accumulation of putrescine in whole leaf tissues, as well as in the apoplastic fluids, which is explained by the induction of its synthesis in plant cells and also on the basis of its excretion by bacteria. We showed that the excretion of this polyamine by P. syringae is stimulated under virulence-inducing conditions, suggesting that it plays a role in plant colonization. However, no activation of bacterial virulence traits or induction of plant invasion was observed after the exogenous addition of putrescine. In addition, no connection was found between this polyamine and plant defence responses. Although further research is warranted to unravel the biological functions of these molecules during plant-bacterial interactions, this study contributes to a better understanding of the changes associated with the homeostasis of polyamines during plant pathogenesis.
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http://dx.doi.org/10.1016/j.jplph.2018.09.014DOI Listing
December 2018

Rice tolerance to suboptimal low temperatures relies on the maintenance of the photosynthetic capacity.

Plant Physiol Biochem 2018 Jun 27;127:537-552. Epub 2018 Apr 27.

Laboratorio de Fisiología de Estrés Abiótico en Plantas, Unidad de Biotecnología 1, IIB-INTECH, CONICET, UNSAM, Chascomús, Argentina. Electronic address:

The purpose of this research was to identify differences between two contrasting rice cultivars in their response to suboptimal low temperatures stress. A transcriptomic analysis of the seedlings was performed and results were complemented with biochemical and physiological analyses. The microarray analysis showed downregulation of many genes related with PSII and particularly with the oxygen evolving complex in the sensitive cultivar IR50. Complementary studies indicated that the PSII performance, the degree of oxygen evolving complex coupling with the PSII core and net photosynthetic rate diminished in this cultivar in response to the stress. However, the tolerant cultivar Koshihikari was able to maintain its energy equilibrium by sustaining the photosynthetic capacity. The increase of oleic acid in Koshihikari could be related with membrane remodelling of the chloroplasts and hence contribute to tolerance. Overall, these results work as a ground for future analyses that look forward to characterize possible mechanisms to tolerate this stress.
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http://dx.doi.org/10.1016/j.plaphy.2018.04.035DOI Listing
June 2018
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