Cry for help from rhizosphere microbiomes and self-rescue strategies cooperatively alleviate drought stress in spring wheat

Abstract

In response to drought, plants modulate their morphology and orchestrate a range of functional adaptations. However, the intricate relationships between plants and their microbiome in response to drought stress are not fully understood. Herein, we used transcriptome and untargeted metabolomics technologies to study genetic and metabolic changes associated with drought resistance in spring wheat, as well as amplicon sequencing and metagenomic approaches were employed to investigate the influence of rhizosphere microorganisms on this process. Results indicated that plant functions of osmotic adjustment, oxidative stress, and stomatal regulation were enriched during drought conditions. Meanwhile, the relative abundances of trehalose, sucrose, gentiobiose, and abscisic acid in root exudates increased by 18.7 %, 21.1 %, 4.8 %, and 121.0 %, respectively. Cross-domain network construction with four omics data revealed that a significant increase in abundance of the trehalose biosynthetic pathway and sugar transporter SWEET gene promoted sucrose and trehalose secretion, respectively, leading to an enrichment of Pseudomonas and Streptomyces in the subsequent validation assay. Pseudomonas extremorientalis LS-8 and Streptomyces cinereoruber LW-5 were isolated to reveal that both strains could improve drought resistance by increasing the average aboveground fresh weight by more than 33.0 % and upregulating the expression of TaLEA2, TaBADHb, TaWRKY10, and TaERF3 in spring wheat. Taken together, our study reveals novel drought resistance insights of spring wheat by the collaboration of self-rescue and cry for help from rhizosphere strategy, providing new opportunities to enhance drought resilience of spring wheat.