Fungal endophytes contribute to enhancing salinity stress tolerance in eggplant (Solanum melongena L.)

Abstract Endophytes benefit the host by enhancing its ability to withstand abiotic and biotic stresses by producing plant-specific hormones and secondary metabolites. The generation of plant hormones like indole acetic acid and gibberellins is one advantage of the mutualistic relationship between the host plant and the endophytes. Thus, the present study was designed to isolate the endophytic fungi from brinjal var. Mattu Gulla under salinity stress conditions. The endophytes were isolated from leaves and roots using the standard protocol and identified based on the morphology of the spores. The effect of salinity on germination of the spores and growth of the endophytes under salinity conditions and its effect on seed germination, root architecture, and gas exchange parameters were studied. Colletotrichum sp. and Curvularia sp. dominated the roots of salt-stressed plants, but Phomopsis sp. dominated the endophyte community in the leaves. Curvularia sp. and Phomopsis sp. are salinity tolerant, based on in vitro investigations of spore germination from isolated endophytes and growth in NaCl mixed media. Additionally, different NaCl concentrations were used to allow the spores of Phomopsis sp. and Curvularia sp. to germinate, and the germ tube length was longer in the 100 mM NaCl treatment group than in the control group. In contrast to the control group, Phomopsis sp. germ tubes decrease in length when exposed to salinity stress. Our research showed that endophyte-conditioned media, for the first time, modifies root architecture and promotes seed germination. The present study describes the endophytic communities of brinjal grown under salinity stress and their plant growth- promoting activity.