Potential of <i>Herbaspirillum</i> and <i>Azospirillum</i> Consortium to Promote Growth of Perennial Ryegrass under Water Deficit

Abstract

Plant growth-promoting bacteria (PGPB) can mitigate the effect of abiotic stresses on plant growth and development; however, the degree of plant response is host-specific. The present study aimed to assess the growth-promoting effect of Herbaspirillum (AP21, AP02), Azospirillum (D7), and Pseudomonas (N7) strains (single and co-inoculated) in perennial ryegrass plants subjected to drought. The plants were grown under controlled conditions and subjected to water deficit for 10 days. A significant increase of approximately 30% in dry biomass production was observed using three co-inoculation combinations (p Herbaspirillum sp. AP21 and Azospirillum brasilense D7 resulted in the highest indolic compound production (p Azospirillum strain showed the highest potential in the in vitro and in silico tests, the plants responded better when PGPB were co-inoculated, demonstrating the importance of integrating in silico, in vitro, and in vivo assessment results when selecting PGPB to mitigate drought stress.

Keywords

• endophytic bacteria
• growth-promoting trait
• drought
• <i>Lolium</i>