Shifts in soil microbial community functional gene structure across a 61-year desert revegetation chronosequence

Vegetation and soil properties are crucial in shaping soil microbial communities. However, little is known about temporal changes in the functional structure of soil microbial communities to managed revegetation in desert ecosystems. Here, we adopted GeoChip 5.0-180 K, a functional gene array, to investigate the succession of soil microbial functional genes structure and potential across a 61-year revegetation chronosequence in the Tengger Desert, China. The abundance of bacterial, fungal and archaeal genes generally increased during succession. However, variation in α-diversity of microbial functional genes and signal intensity of most C-, N- and P-cycling related genes showed hump-shaped patterns along the successional gradient. Although microbial functional structure changed during succession, these revegetation sites shared a high percentage of functional genes and nestedness-resultant component dominantly determined β-diversity. Furthermore, microbial functional structure significantly correlated with crustal and shrub coverage, thickness and mass of crusts, soil fine particles, total C, total P and the ratios of C to N and C to P. The canonical correspondence analysis (CCA) and CCA-based variation partitioning analysis showed that environmental variables explained 56.6% and 85.3% of the variance in overall microbial functional genes, respectively. These results indicate that vegetation development, especially the colonization and development of soil crusts together with changes in soil abiotic properties, play key roles in driving the functional shifts in soil microbial community structure after desert revegetation.