Plant-associated bacteria are essential for host health and productivity, yet their links to environmental drivers remain poorly understood. Using amplicon sequencing of 180 samples, we characterized bacterial communities in the phylloplane, leaf endosphere, root endosphere, rhizosphere, and bulk soil of Alhagi sparsifolia across three basins (Turpan, Tarim–Cele, and Dzungaria–Mosuowan). Actinobacteriota, Proteobacteria, and Firmicutes dominated most compartments, with seasonal exceptions in phylloplane and leaf endosphere communities. In Mosuowan, fewer bacterial phyla were significantly affected in spring than in summer or autumn. Alpha diversity (Chao1) did not differ among regions in the phylloplane and leaf endosphere but varied strongly in the root endosphere, rhizosphere, and bulk soil, with higher richness in autumn. Phylloplane diversity (Pielouₑ, Shannon, Simpson) peaked in spring, whereas leaf endosphere diversity showed the opposite pattern. Season exerted a stronger effect than site on phylloplane and leaf endosphere diversity and on Chao1 in belowground niches, while site effects dominated evenness and diversity indices in the root endosphere, rhizosphere, and bulk soil. Redundancy analysis identified soil total potassium as the most consistent driver of bacterial community variation across all niches (1. 80–4. 13%), with additional influences from root nutrients (total nitrogen and potassium) and temperature (p < 0. 05). Deterministic assembly processes increased from the leaf to the root endosphere, where communities exhibited reduced genetic information processing but enhanced environmental information processing and cellular functions (p < 0. 05). These findings provide a foundation for microbe-based strategies to support desert vegetation and ecosystem stability.
Zhang et al. (2026) studied this question.