Identification of Endophytic Fungi YD09 from Wild Soybean and Its Characteristics in Promoting Growth and Salt Tolerance

In order to screen endophytes with growth promotion and stress resistance from wild soybeans, we used tissue separation method to isolate endophytic fungi from wild soybean roots. The strain was identified according to the morphology and ITS sequence phylogenetic tree. The salt tolerance characteristics of the strain itself was studied, as well as the effects of intracellular and extracellular products on the growth and salt tolerance of soybean seedlings. One endophytic fungus was isolated and identified as Alternaria angustifolia, which was named YD09. The strain YD09 can grow up under 30% NaCl concentration. Strain YD09 has a good promoting effect on soybean seedlings, and make the seedlings resistant to NaCl concentration up to 200 mmol·L^-1. The intracellular product of strain YD09 has a significant resistance promoting effect on soybean seedlings, extracellular products can enhance salt tolerance of soybean seedlings. Strain YD09 has good growth promoting and salt tolerance abilities, which can alleviate the damage of salt stress to soybean seedlings, and it can be used as a new strain resource in agricultural production.