Li Ronglan, Li Dongdong, Guo Yuhang, Wang Yueli, Zhang Yufeng, Li Le, Yang Xiaosong, Chen Shaojiang, Würschum Tobias, Liu Wenxin
Sanya Institute of China Agricultural University, China Agricultural University, Sanya 572025, China.
State Key Laboratory of Maize Bio-Breeding, National Maize Improvement Center, College of Agronomy and Biotechnology, China Agricultural University, Beijing 100193, China.
Int J Mol Sci. 2025 Jun 29;26(13):6285. doi: 10.3390/ijms26136285.
Drought severely limits crop yield every year, making it critical to clarify the genetic basis of drought tolerance for breeding of improved varieties. As drought tolerance is a complex quantitative trait, we analyzed three phenotypic groups: (1) agronomic traits under well-watered (WW) and water-deficit (WD) conditions, (2) stress tolerance indices of these traits, and (3) phenotypic plasticity, using a multi-parent doubled haploid (DH) population assessed in multi-environment trials. Genome-wide association studies (GWAS) identified 130, 171, and 71 quantitative trait loci (QTL) for the three groups of phenotypes, respectively. Only one QTL was shared among all trait groups, 25 between stress indices and agronomic traits, while the majority of QTL were specific to their group. Functional annotation of candidate genes revealed distinct pathways of the three phenotypic groups. Candidate genes under WD conditions were enriched for stress response and epigenetic regulation, while under WW conditions for protein synthesis and transport, RNA metabolism, and developmental regulation. Stress tolerance indices were enriched for transport of amino/organic acids, epigenetic regulation, and stress response, whereas plasticity showed enrichment for environmental adaptability. Transcriptome analysis of 26 potential candidate genes showed tissue-specific drought responses in leaves, ears, and tassels. Collectively, these results indicated both shared and independent genetic mechanisms underlying drought tolerance, providing novel insights into the complex phenotypes related to drought tolerance and guiding further strategies for molecular breeding in maize.
干旱每年都会严重限制作物产量，因此阐明耐旱性的遗传基础对于培育改良品种至关重要。由于耐旱性是一个复杂的数量性状，我们分析了三个表型组：（1）在充分供水（WW）和水分亏缺（WD）条件下的农艺性状，（2）这些性状的胁迫耐受性指数，以及（3）表型可塑性，使用在多环境试验中评估的多亲本双单倍体（DH）群体。全基因组关联研究（GWAS）分别为这三组表型鉴定出130、171和71个数量性状位点（QTL）。所有性状组之间仅共享一个QTL，胁迫指数和农艺性状之间共享25个，而大多数QTL是其所在组特有的。候选基因的功能注释揭示了这三个表型组的不同途径。WD条件下的候选基因在胁迫响应和表观遗传调控方面富集，而WW条件下的候选基因在蛋白质合成与运输、RNA代谢和发育调控方面富集。胁迫耐受性指数在氨基酸/有机酸运输、表观遗传调控和胁迫响应方面富集，而可塑性在环境适应性方面富集。对26个潜在候选基因的转录组分析表明，叶片、果穗和雄穗中存在组织特异性干旱响应。总体而言，这些结果表明了耐旱性背后既有共享的遗传机制，也有独立的遗传机制，为与耐旱性相关的复杂表型提供了新的见解，并为玉米分子育种的进一步策略提供了指导。
