Rhizospheres of Rubus ellipticus and Ageratina riparia from Meghalaya exhibit Actinomycetota that promote plant growth

Abstract

The mounting pressure on food security due to the increasing human population and climate change has prompted environment-friendly approaches to increase food crop productivity. Medicinal plant-associated microorganisms offer a solution due to their capability to antagonize phytopathogens and promote plant growth. Rhizosphere-dwelling Actinomycetota, which are mostly Gram-positive bacteria with high DNA G + C content, are potential plant growth promoters and biocontrol agents. Due to the infancy of research in medicinal plant-associated rhizosphere Actinomycetota, especially in the state of Meghalaya, India, they were isolated from the rhizospheres of two medicinal plants, Rubus ellipticus and Ageratina riparia, from Meghalaya, and the isolates were evaluated for their antimicrobial and plant growth-promoting (PGP) activities. Several antimicrobial Amycolatopsis strains were isolated from the rhizosphere of R. ellipticus and PGP Streptomyces strains from the rhizosphere of A. riparia. Five isolates were selected and tested for their ability to promote plant growth on tomato plants. All of them could significantly increase seedling vigor and plant growth on soil amended with organic manure. Plant-associated Actinomycetota from the rhizospheres of the two medicinal plants, therefore, exhibited their potential as bioinoculants that can be further developed and applied for increased crop productivity and for the maintenance of food security.