Institute of Vegetable Science, Zhejiang University, Hangzhou 310058, China.
Hainan Institute of Zhejiang University, Yazhou District, Sanya 572025, China.
Int J Mol Sci. 2023 Dec 20;25(1):65. doi: 10.3390/ijms25010065.
Drought stress has detrimental effects on crop productivity worldwide. A strong root system is crucial for maintaining water and nutrients uptake under drought stress. Wild watermelons possess resilient roots with excellent drought adaptability. However, the genetic factors controlling this trait remain uninvestigated. In this study, we conducted a bulk segregant analysis (BSA) on an F population consisting of two watermelon genotypes, wild and domesticated, which differ in their lateral root development under drought conditions. We identified two quantitative trait loci ( and ) associated with the lateral root response to drought. Furthermore, we determined that a small region (0.93 Mb in ) is closely linked to drought adaptation through quantitative trait loci (QTL) validation and fine mapping. Transcriptome analysis of the parent roots under drought stress revealed unique effects on numerous genes in the sensitive genotype but not in the tolerant genotype. By integrating BSA, fine mapping, and the transcriptome, we identified six genes, namely L-Ascorbate Oxidase (AO), Cellulose Synthase-Interactive Protein 1 (CSI1), Late Embryogenesis Abundant Protein (LEA), Zinc-Finger Homeodomain Protein 2 (ZHD2), Pericycle Factor Type-A 5 (PFA5), and bZIP transcription factor 53-like (bZIP53-like), that might be involved in the drought adaptation. Our findings provide valuable QTLs and genes for marker-assisted selection in improving water-use efficiency and drought tolerance in watermelon. They also lay the groundwork for the genetic manipulation of drought-adapting genes in watermelon and other species.
干旱胁迫对全球作物生产力有不利影响。一个强壮的根系对于在干旱胁迫下维持水分和养分吸收至关重要。野生西瓜具有有弹性的根系和出色的耐旱适应性。然而，控制这种特性的遗传因素尚未被研究。在这项研究中，我们对一个由两个西瓜基因型组成的 F 群体进行了 bulk segregant analysis (BSA)，这两个基因型在干旱条件下的侧根发育方面存在差异。我们鉴定出两个与侧根对干旱反应相关的数量性状位点 ( 和 )。此外，我们通过数量性状位点 (QTL) 验证和精细定位确定，一个小区域 (0.93 Mb) 与耐旱性密切相关。干旱胁迫下亲本根系的转录组分析显示，在敏感基因型中，许多基因受到独特影响，但在耐受基因型中则没有。通过 BSA、精细定位和转录组分析，我们鉴定出六个基因，即 L-抗坏血酸氧化酶 (AO)、纤维素合酶互作蛋白 1 (CSI1)、晚期胚胎丰富蛋白 (LEA)、锌指 Homeodomain 蛋白 2 (ZHD2)、周缘细胞因子类型-A5 (PFA5) 和 bZIP 转录因子 53 样 (bZIP53-like)，它们可能参与了耐旱性。我们的研究结果为在西瓜和其他物种中提高水分利用效率和耐旱性的标记辅助选择提供了有价值的 QTL 和基因。它们还为西瓜和其他物种耐旱适应基因的遗传操作奠定了基础。
