Abstract
BACKGROUND: Global climate change has intensified the frequency and severity of drought events, posing significant threats to agriculture in arid regions. As an important economic crop, cotton is highly vulnerable to drought stress, which adversely affects its growth, yield, and associated soil microbial communities. AIMS: This study aimed to conduct an in-depth investigation the effects of drought hardening on cotton root physiology and rhizosphere microbial dynamics by integrating physiological and metagenomic analyses. By analyzing aboveground responses and yield performance of cotton, this study sought to elucidate the comprehensive impact of drought hardening on cotton growth and yield, with the goal of providing a scientific basis for water-saving irrigation strategies in cotton fields in arid regions. METHODS: The experiment was conducted in 2024 at Huaxing Farm in Changji, Xinjiang, using the Zhongmian 113 variety. The experiment used the field water requirement as the control (CK, including the water for seedling emergence, totaling 4950 m³/ha), and set three different drought hardening treatments: mild (D1, with 20% water saving during the seedling stage), moderate (D2, with 30% water saving during the seedling stage), and severe (D3, with 40% water saving during the seedling stage). Compared with the control, the total water savings for the entire growth period of treatments D1, D2, and D3 were 12.5%, 15%, and 17.5%, respectively. RESULTS: Based on the performance of cotton growth, development, and yield, the D1 treatment significantly enhanced the antioxidant capacity of cotton roots and effectively maintained cell membrane integrity. Additionally, the D1 treatment significantly altered the diversity of soil fungi, to some extent, this water management practice optimized the structure of the microbial community, and promoted the formation of the dominant bacterial group, Gemmatimonadales. CONCLUSIONS: The study preliminarily revealed the interaction between Gemmatimonadales and cotton roots during the budding stage. Meanwhile, through a comprehensive analysis of cotton growth characteristics, root physiological and biochemical processes, and yield performance, it was shown that the stress resistance of cotton was enhanced under the D1 treatment. This research provided a scientific basis for water-saving irrigation strategies in cotton fields in arid regions, demonstrating that under the D1 condition, it is possible to enhance the stress resistance of cotton while conserving water.