Rizobacterias promotoras de crecimiento en Guarianthe skinneri (Orchidaceae)

Abstract

The Guarianthe skinneri orchid is included in NOM-059-ECOL-2010, Mexico standard as an endangered species. In order to study PGPR (promoting growth plant rhizobacteria) from this orchid, 10 roots were collected from different plants to isolate bacteria associated with the roots, which were analyzed by in vitro tests such as: production of AIA, nitrogen fixation, interaction with the mycorrhizal fungus Thanatephorus sp. strain RG26 and phosphate solubilization. We obtain 71 bacterial isolates, 10 strains of them were characterized by sequencing with the 16d rDNA marker identifying six bacteria: Sphingomonas sp. Sinorhizobium sp. Bacillus sp. Nocardia cerradoensis, Bacillus megaterium and Burkholderia phytofirmans. We observed that the bacterium Sinorhizobium sp. produced a greater amount of AIA (69.189 μg/ml) and Bacillus sp. performed greater acetylene reduction (10.251 nmol cultivo/96h). In the interactions of the bacteria and the fungus RG26, four categories were presented (extremely positive, positive, antagonism 50-50 and inhibition). In relation to the solubilization of phosphate, Burkholderia phytofirmans presented higher IS after 48 and 96 hr with an IS of 3.11 and 3.48, respectively. The results indicate that Bacillus sp. it could have the best characteristics to promote the development of the G. skinneri orchid by inoculating seeds and seedlings.

Mycorrhizal status of Guarianthe skinneri (Orchidaceae) in urban trees in Tapachula, Chiapas, Mexico

“…Extending the sampling to more urban phorophytes will allow us to confirm this specificity for a large species of mycorrhizal fungi of the Tulasnellaceae family in adult plants, as well as to test the specificity through symbiotic propagation to implement propagation technologies. Together with previous studies conducted on G. skinneri (Aguilar Diaz et al, 2018;Coello et al, 2010;Coutiño-Cortés et al, 2017;), we propose to employ these species in urban environments as a sustainable strategy in order to conserve the remaining wild populations in nature.…”

Fungi diversity in roots of Guarianthe skinneri in urban condition: velamen versus cortex

“…Thus, it is logical to think that the numerous taxa that can inhabit the abiotic velamen would reduce their frequency when colonizing living tissue that applies defense and interaction mechanisms. Although this study is fungi-centered it is necessary to consider that there are root interactions with bacteria (Aguilar et al, 2018), meaning thar there are complex interactions. There are statistically significant differences between the two sample groups, showing that velamen has more fungal diversity than the cortex.…”