Bioprospecting endophytic bacteria from xerophytic plants for inducing drought tolerance in rice: a climate change adaptation strategy

Climatic drought is one of the major abiotic stress bedeviling the cultivation of rice which is the primary staple food for more than two-third of the world's population. This study explored the potentials of endophytic bacteria from xerophytic plants (Hyphaene thebaica, Acacia albida, Piliostigma reticulatum and Ziziphus mauritiana) in Jigawa state, Nigeria for inducing drought tolerance in rice. Roots were collected from trees’ rhizosphere zones and cultured for bacteria using standard methods. Colonies were identified and assessed for drought tolerance using polyethylene glycol, rice seedlings were inoculated and grown while growth and yield parameters were monitored. ANOVA was used to determine the differences and principal component analysis was used to evaluate the microbial contributions from different trees to the overall growth and yield parameters variation. There were nine bacterial species altogether with Bacillus amyloliquefaciens occurring in all the trees and Acacia albida had the highest number (7) of bacterial species. Highest phosphate solubilization index, Nitrogen fixation and Auxin syntheses were observed in P. putida (4.10±1.03 mg L−1), P. fluorescens (9.31±2.83 mg L−1) and B. amyloliquefaciens (13.56±4.16 mg L−1) from A. albida. Growth and yield parameters which culminated into harvest index was highest (0.40) in A. albida treated rice and lowest (0.28) in the control. Four principal components (PCs) accounted for overall variations in growth and yield parameters with PCs 1 and 2 representing contributions from A. albida and Z. mauritiana accounting for about 99.98%. These xerophytes and their rhizosphere microbes should therefore be propagated and applied to overcome drought challenges in crop production.