Lotus asociated microrganisms

AMIRA S. NIEVA

Chascomús

Workshop; V Lotus spp Workshop; 2016

The forage legume Lotus tenuis is an appealing alternative to meet the needs for cattle production in the Flooding Pampa region, Argentina. The use of chemical compounds for agriculture practices, in addition to the removal of native vegetation, eventually may change the diversity of other ecosystem components such as bacterial communities. To examine the effect of of L. tenuis promotion with herbicides on the soil bacetrial community and taxonomic composition, we studied three different rangeland sites of the Flooding Pampa region. At each site, two paddocks were compared: one managed to promote the forage legume L. tenuis, and the other lacking of management history and hence, covered by natural grasses. To asses bacterial diversity we used 454-FLX pyrosequencing technology of the V4 region of the 16S rRNA gene, on genomic DNA extracted from soil samples. Our results suggest that 5-6 years of land use with L. tenuis promotion does not affect the microbial community structure in this ecosystem, evidenced in the non-differences between the treatments for diversity indices. Endophytes microorganism provide a wide range of benefits to their hosts. Its potential use as biofertilizers can become a sustainable low-cost technology. However it has been shown that endophytes-plant interactions are highly variable in the ecosystem, occurring along the continnum from antagonistic to mutualistic interactions. Fungal endophytes isolated from lotus roots were evaluated according their phosphate solubilizing capability and tolerance to soil extreme conditions. Our results shown that several strains grow in a wide pH range and salinity conditions. Two Lotus species were infected by one of the isolated strains. The interaction effect was contrasting between them, evidenced by a growth promotion in one versus a decrease in biomass production in the other one. These results suggest that the use of fungal endophytes as biofertlizers should be studied in depth before its use in a specific host.