Sun Xuelian, Kang Xin, Wang Jiayan, He Xiaoyan, Liu Wenxing, Xu Dengan, Dai Xuehuan, Ma Wujun, Zeng Jianbin
College of Agronomy, Qingdao Agricultural University, Qingdao 266109, China.
Int J Mol Sci. 2025 Sep 5;26(17):8659. doi: 10.3390/ijms26178659.
Alkaline stress, driven by high pH and carbonate accumulation, results in severe physiological damage in plants. While the molecular mechanisms underlying alkaline tolerance have been partially elucidated in many crops, they remain largely unexplored in wheat. We hypothesize that alkaline stress tolerance in wheat is genotype-dependent. This study employed an integrated multi-omics approach to assess alkaline stress responses, combining genome-wide association study (GWAS) and RNA-seq analyses. Systematic phenotyping revealed severe alkaline stress-induced root architecture remodeling-with 57% and 73% length reductions after 1- and 3-day treatments, respectively-across 258 accessions. Analysis of the GWAS results identified nine significant alkaline tolerance QTLs on chromosomes 1A, 3B, 3D, 4A, and 5B, along with 285 associated candidate genes. Using contrasting genotypes-Dingxi 38 (tolerant) and TDP.D-27 (sensitive)-as experimental materials, physiological analyses demonstrated that root elongation was less inhibited in Dingxi 38 under alkaline stress compared to TDP.D-27, with superior root integrity observed in the tolerant genotype. Concurrently, Dingxi 38 exhibited enhanced reactive oxygen species (ROS) scavenging capacity. Subsequent RNA-seq analysis identified differentially expressed genes (DEGs) involved in ion homeostasis, oxidative defense, and cell wall remodeling. Integrated GWAS and RNA-seq analyses allowed for the identification of seven high-confidence candidate genes, including transcription factors (MYB38, bHLH148), metabolic regulators (ATP-PFK3), and transporters (OCT7), elucidating a mechanistic basis for adaptation to alkaline conditions. These findings advance our understanding of alkaline tolerance in wheat and provide candidate targets for molecular breeding of saline- and alkaline-tolerant crops.
由高pH值和碳酸盐积累驱动的碱性胁迫会对植物造成严重的生理损害。虽然许多作物中耐碱性的分子机制已得到部分阐明，但在小麦中仍基本未被探索。我们假设小麦的耐碱性是基因型依赖的。本研究采用综合多组学方法来评估碱性胁迫反应，结合了全基因组关联研究（GWAS）和RNA测序分析。系统表型分析揭示了在258份种质中，碱性胁迫会导致严重的根系结构重塑——在1天和3天处理后，根长分别减少了57%和73%。对GWAS结果的分析在1A、3B、3D、4A和5B染色体上鉴定出9个显著的耐碱性QTL，以及285个相关候选基因。以对比基因型——定西38（耐碱）和TDP.D - 27（敏感）——作为实验材料，生理分析表明，与TDP.D - 27相比，碱性胁迫下定西38的根伸长受到的抑制较小，在耐碱基因型中观察到更好的根系完整性。同时，定西38表现出增强的活性氧（ROS）清除能力。随后的RNA测序分析鉴定出参与离子稳态、氧化防御和细胞壁重塑的差异表达基因（DEG）。整合GWAS和RNA测序分析能够鉴定出7个高可信度候选基因，包括转录因子（MYB38、bHLH148）、代谢调节因子（ATP - PFK3）和转运蛋白（OCT7），阐明了适应碱性条件的机制基础。这些发现增进了我们对小麦耐碱性的理解，并为耐盐碱作物的分子育种提供了候选靶点。
