Metagenomic insight into drought-induced changes in the Egyptian wheat rhizosphere microbiome.

Wheat is one of the most important cereal crops and an important source of food for billions of people worldwide. However, drought stress can pose a real threat to its productivity and lead to significant yield losses, especially in Egypt. The rhizospheric microbiome of wheat can play an important role in drought stress and help wheat to respond to this abiotic stress. Understanding this microbiome is therefore also important to improve drought stress resilience and productivity. In this study, a metagenomic analysis was performed to investigate how the composition and diversity of microbial communities associated with the wheat rhizosphere change under drought. Taxonomic and phylogenetic analyses revealed a shift in microbial abundance, with Actinobacteria, Bacteroidetes, Proteobacteria and Verrucomicrobia being the four most abundant phyla of the ethnic microbiota. Remarkably, other classes, including Alphaproteobacteria and Cytophagia, were significantly enriched under drought, which could be a promising enhancement of plant stress altruism. Differential abundance analysis showed that the control samples had higher abundance of microbial taxa such as OD1, WS2, Chlorobi, ABY1 and SHA-109 compared to the drought-treated genotypes. Functional prediction analysis using PICRUSt showed that an uncharacterized ATP-binding protein within the AAA + superfamily is overrepresented under drought conditions. This suggests that these genes may play a role in stress adaptation, possibly via energy-dependent regulation of cellular processes involved in plant survival. Our results expand our understanding of the complexity of responses of the wheat rhizosphere microbiome to drought and have practical implications for the development of microbial target combinations to improve wheat tolerance and productivity in the context of climate change challenges.