Extremophile Microorganism with Potential Plant Growth Promoter to Mitigate Salt Stress in Soybeans

FARIAS MARIA EUGENIA; SANTOS ANA PAULA ; BELFIORE CAROLINA

Buenos Aires

Simposio; Simposio en Biociencias 3; 2018

CONICET

In a global scale, Argentina is the leading exporter of soybean oil and flour and the third largest producer of soybeans. Therefore, the cultivation of soybean is of great importance for the national economy. Due to the economic importance of the crop, the main factors that can negatively affect its productivity have been identified. The salinity tends change the agronomically useful lands into unproductive areas. Our country presents 85 million hectares with salinity problems, therefore, if we don?t solve this problem we will soon face the situation of the lack of enough food in the world. Other problem that carry this crop is de infection with Macrophomina phaseolina. This fungus causes the phenomenon called ?carbonaceous rot?, the roots start changing their aspect, withe to grey, and then the infection progress to all the plant.Plant growth promoting bacteria (PGPB) are a useful alternative strategy for salt tolerance in plants. They colonize the plant rhizosphere and confer beneficial effects such as the production of indole-3-acetic-acids (IAA), aminocyclopropane-1-carboxylate (ACC) deaminase, N2-fixation and antagonism effects. The use of halotolerant PGPB are environmentally friendly and they are an inexpensive strategy for a better crop production and conservation in salt affected areas.The aim of this study was to evaluate the effect of saline stress in the promoting properties of Stenotrophomona sp., isolated from Andean wetland and their antagonism effect against Macrophomina phaseolina.The results showed that Stenotrophomona sp. have a high salt resistance. Under saline stress (220mM) produce siderophores, ACC-deaminase, and N2-fixation. At higher concentrations (1400mM), the strain maintained the ability to solubilize phosphate and produce a greater concentration of AIA as the concentration of salt increases. In saline germination essays, they increase the percent of germination seeds. In addition, the bacteria show an antifungal activity against M.phaseolina, inhibiting the 36,2% the radial growth.These results encourage continued studies for the use of Stenotrophomona sp. as an antifungal alternative and to improve the response of soybean affected by saline soils.