Publications by authors named "Iván Oros-Ortega"

2 Publications

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Seasonal shifts of arbuscular mycorrhizal fungi in Cocos nucifera roots in Yucatan, Mexico.

Mycorrhiza 2020 May 2;30(2-3):269-283. Epub 2020 Apr 2.

Unidad de Biotecnología, Centro de Investigación Científica de Yucatán, Mérida, Yucatán, Mexico.

The diversity and community structure of arbuscular mycorrhizal fungi (AMF) associated with coconut (Cocos nucifera) roots was evaluated by next generation sequencing (NGS) using partial sequences of the 18S rDNA gene and by spore isolation and morphological identification from rhizosphere soil. Root samples from six different Green Dwarf coconut plantations and from one organic plantation surrounded by tropical dry forest along the coastal sand dunes in Yucatan, Mexico, were collected during the rainy and dry seasons. In total, 14 root samples were sequenced with the Illumina MiSeq platform. Additionally, soil samples from the dry season were collected to identify AMF glomerospores. Based on a 95-97% similarity, a total of 36 virtual taxa (VT) belonging to nine genera were identified including one new genus-like clade. Glomus was the most abundant genus, both in number of VT and sequences. The comparison of dry and rainy season samples revealed differences in the richness and composition of AMF communities colonizing coconut roots. Our study shows that the main AMF genera associated with coconut tree roots in all samples were Glomus, Sclerocystis, Rhizophagus, Redeckera, and Diversispora. Based on glomerospore morphology, 22 morphospecies were recorded among which 14 were identified to species. Sclerocystis sinuosa, Sclerocystis rubiformis, Glomus microaggregatum, and Acaulospora scrobiculata were dominant in field rhizosphere samples. This is the first assessment of the composition of AMF communities colonizing coconut roots in rainy and dry seasons. It is of importance for selection of AMF species to investigate for their potential application in sustainable agriculture of coconut.
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http://dx.doi.org/10.1007/s00572-020-00944-0DOI Listing
May 2020

[Colonization and structure of arbuscular mycorrhizal fungi community in Alsophila firma (Cyatheales: Cyatheaceae) from a tropical montane cloud forest in Veracruz, México].

Rev Biol Trop 2014 Dec;62(4):1609-23

Alsophila firma is a tree fern that is distributed mainly in tropical montane cloud forest (TMCF) and is considered as a threatened species. Arbuscular mycorrrhizal fungi (AMF) have been proposed as an alternative in rescue programs of endangered species. However, our knowledge about diversity of AMF and mycorrhizal status of the species of TMCF is limited. In Mexico TMCF shows different degrees of conservation because of fragmentation and land use change. In this study, we evaluated the level of colonization, richness and abundances of spores of AMF in three fragments with different conservation status: conserved (100 years), secondary vegetation (17 years) and disturbed. For this, soil samples and roots were collected from five individuals of A. firma per site, with at least 100 m away from each other; a total of 100 cm of roots were analysed per site. Root samples showed AMF and occasionally dark septate fungi (DSF) colonizations. For the overall study, 19 species of AMF were recorded: Gigaspora (7), Acaulospora (4), Glomus (4), Funneliformis (2), Sclerocystis (1) and Scutellospora (1). The dominant species in the three sites were Funneliformis geosporum and Acaulospora scrobiculata. The highest diversity (H') and evenness (J') (p < 0.05) were found in the conserved site (H' = 1.7, J' = 0.66), when compared to the secondary vegetation (H' = 1.5, J' = 0.61), and the disturbed site (H' = 0.74, J' = 0.41). Statistical analysis showed that the AMF degree of colonization was significantly higher (p < 0.05) in the conserved site; although, the disturbed site showed low richness and abundances of AMF, the degree of root colonization did not differ statistically (p < 0.05) with the secondary vegetation site. Chao2 (Richness estimation model) showed that the number of analysed samples were sufficient to represent the structure of the AME communities with values > 90%. The present study confirmed that A. firma is a mycorrhizal species that exhibits high levels of colonization even in disturbed sites. We suggest that F. geosporum and A. scrobiculata may have the potential to inoculate the gametophyte and young sporophyte of A. firma, to support restoration programs, because of their abundances and high tolerance to disturbed sites.
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December 2014