Microbe-induced plant drought tolerance by ABA-mediated root morphogenesis and epigenetic reprogramming of gene expression

The use of beneficial microbes to mitigate drought stress tolerance of plants is of great potential albeit little understood. We show here that a root endophytic desert bacterium, Pseudomonas argentinensis sp. SA190, enhances drought stress tolerance in Arabidopsis. Transcriptome and genetic analysis demonstrate that SA190-induced root morphogenesis and gene expression is mediated via the plant abscisic acid (ABA) pathway. Moreover, we demonstrate that SA190 primes the promoters of target genes in an epigenetic manner which is ABA-dependent. Application of the SA190 priming technology on crops is demonstrated for alfalfa in field trials, showing enhanced performance under desert agriculture conditions. In summary, a single beneficial root bacterial strain can help to perform agriculture under drought and water limiting conditions. Synopsis Beneficial root endophyte Pseudomonas argentinensis sp. SA190 confers drought tolerance in plants SA190 modulates the expression of genes under drought stress in an ABA-dependent manner SA190 primes genes via H3K4me3 histone mark enrichment SA190 alters host plant physiology by improving the plant water status SA190 enhances crop performance in open field conditions with limited irrigation