Nucleotides enriched under heat stress recruit beneficial rhizomicrobes to protect plants from heat and root-rot stresses.

Abstract

Background: Plants thrive under biotic and abiotic stresses with the help of rhizomicrobiota. Root exudates play a pivotal role in recruiting beneficial microbes that assist plants in surviving environmental challenges, but the mechanisms of plant-microbiome interactions to resist multiple stresses remain elusive. We investigated how heat stress alters the rhizomicrobiomes of Panax notoginseng and how these heat stress-regulated microbes confer enhanced heat tolerance and disease resistance.

Results: We revealed that heat stress at 36 °C caused thermal damage to plants while enhancing heat tolerance and disease resistance for the survival of subsequent plants. Specifically, the beneficial microbes Burkholderia sp. and Saitozyma podzolica were recruited by the heat-stressed P. notoginseng and were confirmed to be responsible for resisting multiple stresses. Heat stress-induced plant roots secrete nucleotides such as purines and pyrimidines to promote the proliferation of these two beneficial microbes rather than root-rot pathogens. The exogenous application of these nucleotides to natural soil also resulted in the enrichment of the same beneficial microbes. Cross-species validation experiments in Capsicum annuum (pepper) and Solanum lycopersicum (tomato) further demonstrated that co-application of nucleotides with beneficial microbes synergistically enhanced heat tolerance.

Conclusions: Our findings highlight a plant strategy for thriving under multiple adversities and propose a potential pathway by leveraging nucleotide-mediated recruitment of beneficial microbes for enhancing plant resilience against multiple stresses. Video Abstract.