Deciphering crop-specific rhizobacteriome assembly in cotton, sorghum, and soybean under hot semi-arid field conditions in Texas.

Background: Different crops may recruit specific rhizosphere microbiomes that support their survival under unfavorable conditions, including hot semi-arid climates. However, the processes driving microbiome assembly within different crops and their adaptation to such extreme environmental conditions remain poorly understood. This study investigates whether upland cotton (Gossypium hirsutum), sorghum (Sorghum bicolor), and soybean (Glycine max) recruit distinct or overlapping rhizospheric bacterial communities under hot semi-arid conditions in Lubbock, Texas, United States, with a focus on their potential role in enhancing crop resilience. By exploring rhizobacterial recruitment strategies and differential microbial associations in these crops, this study addresses critical gaps in plant-microbiome interactions and paves the way for practical applications in hot semi-arid agricultural systems.

Results: We found that the abundances and structures of rhizospheric bacterial communities differed among sorghum, soybean, and cotton, with the differences being closely linked to their predicted functional roles in stress adaptation and nutrient assimilation. Alpha and beta diversity analyses revealed that soybean rhizosphere exhibited the highest bacterial richness and diversity followed by cotton. In contrast, sorghum rhizobacteriome showed the lowest richness and less even distribution of rhizobacterial taxa compared with the other two crops, emphasizing crop-specific rhizobacterial associations. Actinobacteriota and Firmicutes phyla were significantly enriched in sorghum rhizosphere, whereas Pseudomonadota, Bacteroidota, and Acidobacteriota phyla were significantly enriched in soybean and cotton rhizospeheres under hot semi-arid conditions. Functional prediction analysis demonstrated that sorghum-associated rhizobacteriome was significantly enriched in pathways related to stress adaptation, while soybean and cotton rhizobacteriomes exhibited more diverse pathways, primarily associated with nitrogen and sulfur assimilation.

Conclusions: These findings underscore the influence of crop-specific factors in shaping rhizobacteriome composition and function to ensure their behavior and performance under hot semi-arid conditions in Lubbock, Texas, United States, with sorghum favoring stress adaptation, soybean being linked to nitrogen and sulfur assimilation, and cotton displaying intermediate traits. Our results highlight the potential for leveraging rhizobacteriome in developing innovative cultivation strategies to enhance crop resilience and productivity under challenging environmental conditions.