NRPS gene dynamics in the wheat rhizoplane show increased proportion of viscosin NRPS genes of importance for root colonization during drought.

Secondary metabolites are bioactive compounds, diverse in structure, with versatile ecological functions, including key roles in mediating interactions between microorganisms and plants. Importantly, these compounds can promote the colonization of plant surfaces, such as roots, or modulate root exudates to enhance microbial recruitment and establishment. However, owing to the vast diversity of secondary metabolites, their importance in plant root colonization-particularly under stress conditions, such as drought-remains unclear. To determine the involvement of some of these secondary metabolites in root colonization, we used amplicon sequencing targeting the adenylation domain of the non-ribosomal peptide synthases (NRPSs) and the 16S rRNA gene from the rhizoplane of wheat grown in soil under normal and drought stress conditions. Results showed that drought transiently affected the bacterial community composition and the NRPS composition in the rhizoplane. We observed that drought selected for distinct groups of siderophores from different taxonomical groups, enriching for