Potential of endophytes from medicinal plants for biocontrol and plant growth promotion

Endophytic microbes living in medicinal plants were isolated and screened for inhibition of several pathogenic fungi and for plant growth promotion and biocontrol indicators. Of 369 isolates from 13 medicinal plants, 94 isolates had antifungal acitivity against the phytopathogenic fungus Dothiorella gregaria; they were assigned to 9 genera based on analysis of the 16S rRNA gene sequence. Antifungal activity against Sclerotinia sclerotiorum and Botryosphaeria dothidea, the presence of genes coding for type I polyketide synthases (PKSs) and PKSs for a polyene component, chitinase activity, and production of siderophores and indole-3-acetic acid were also evaluated. Four selected representative antagonistic endophytes (SLS23, SSD41, SSD49 and SSD60) and their biocontrol and plant-growth-promoting activities were studied. These isolates significantly improved the growth of soybean and tomato and varied in their control efficacy against plant diseases caused by S. sclerotiorum and B. dothidea. Potential benefits of using endophytes for sustainable practices in a plant production system are also discussed.