Novel endophytic fungus Leptosphaeria sp. strain T-2 improves plant growth and environmental stress tolerance.

Drought and salinity stress pose threats to agricultural production in drylands. Although breeding and genetic modification techniques have been employed to develop drought- and salt-tolerant crops, these methods are costly and risky. Hence, the potential application of endophytic fungi in dryland agriculture is being explored as a novel approach in improving plant tolerance to environmental stress. In this study, endophytic fungi with growth-promoting effects were isolated, characterized, and evaluated in terms of their ability to confer drought and stress tolerance to their host plants. Seventy-seven growth-promoting endophytic fungi belonging to 20 genera were isolated from barley roots; of these, strain T-2 elicited remarkable effects on plant growth parameters. Phylogenetic analysis revealed that strain T-2 belongs to genus Leptosphaeria, whose members are generally known as plant pathogens. Thus, Leptosphaeria sp. strain T-2 is a novel endophytic fungus that promotes plant growth. Moreover, it alleviated growth inhibition caused drought and salinity stress, as evidenced by the survival and maintained health of lettuce plants inoculated with strain T-2. The results of this study suggest that strain T-2 can be applied as a biofertilizer to improve agricultural production in drylands.