Endophytic bacteria with host-supportive genetic determinants in their genomes induce growth and antioxidant activity related gene functions in transcriptome of black rice (Oryza sativa L.)

Abstract

Black rice is famed because of its high antioxidants content. The cooperation and contribution of endophytes towards growth and antioxidant properties of black rice has been experimented. The efficient endophytes were isolated from black rice, and Enterobacter sp., Kluyvera sp. and Bacillus subtilis were selected. The whole genome of these endophytes contained genes required for IAA production (trpAB.Z), phosphate solubilization (pqqAB), siderophore production (entABCD), colonization (fliAB.Z; cheAB.Z) and antioxidant activity (bglAB), which were further validated through biochemical and physiological analysis. The inoculation of these three effective endophytes resulted in enhancement of growth by 33.33%, 30.23% and 33.33% and antioxidant properties by 31.57%, 35.33% and 27.87% in Enterobacter, Kluyvera and B. subtilis treated plants respectively. The transcriptome of black rice plant, when colonized by these endophytes, resulted in 506 up-regulated and 332 down-regulated genes. Transcripts upregulated in response to endophytic colonization were mainly involved in plant growth, antioxidant properties, interactions, and synthesis of aroma compounds (terpenoid synthase). The overall patterns of functions encoded on the genome of endophytes and expressed in black rice plants were highly correlated. The strain specific augmentation through endophytism was used to achieve the desired properties in black rice.