State Key Laboratory of Plant Physiology and Biochemistry, College of Biological Sciences, China Agricultural University, Beijing, 100094, China.
Laboratory of Agrobiotechnology and National Maize Improvement Center of China, Department of Agronomy and Biotechnology, China Agricultural University, Beijing, 100193, China.
New Phytol. 2021 Jun;230(6):2355-2370. doi: 10.1111/nph.17323. Epub 2021 Mar 26.
The farmland of the world's main corn-producing area is increasingly affected by salt stress. Therefore, the breeding of salt-tolerant cultivars is necessary for the long-term sustainability of global corn production. Previous studies have shown that natural maize varieties display a large diversity of salt tolerance, yet the genetic variants underlying such diversity remain poorly discovered and applied, especially those mediating the tolerance to salt-induced osmotic stress (SIOS). Here we report a metabolomics-driven understanding and genetic improvement of maize SIOS tolerance. Using a LC-MS-based untargeted metabolomics approach, we profiled the metabolomes of 266 maize inbred lines under control and salt conditions, and then identified 37 metabolite biomarkers of SIOS tolerance (METO1-37). Follow-up metabolic GWAS (mGWAS) and genotype-to-phenotype modeling identified 10 candidate genes significantly associating with the SIOS tolerance and METO abundances. Furthermore, we validated that a citrate synthase, a glucosyltransferase and a cytochrome P450 underlie the genotype-METO-SIOS tolerance associations, and showed that their favorable alleles additively improve the SIOS tolerance of elite maize inbred lines. Our study provides a novel insight into the natural variation of maize SIOS tolerance, which boosts the genetic improvement of maize salt tolerance, and demonstrates a metabolomics-based approach for mining crop genes associated with this complex agronomic trait.
世界主要玉米产区的农田日益受到盐胁迫的影响。因此，培育耐盐品种对于全球玉米生产的长期可持续性是必要的。先前的研究表明，天然玉米品种表现出很大的耐盐多样性，但这种多样性的遗传变异仍然很少被发现和应用，特别是那些介导耐盐诱导渗透胁迫（SIOS）的遗传变异。在这里，我们报告了一种基于代谢组学的理解和遗传改良玉米 SIOS 耐受性的方法。我们使用基于 LC-MS 的非靶向代谢组学方法，对 266 个玉米自交系在对照和盐胁迫条件下的代谢组进行了分析，然后鉴定出 37 个与 SIOS 耐受性相关的代谢物生物标志物（METO1-37）。随后的代谢 GWAS（mGWAS）和基因型-表型建模确定了 10 个候选基因，这些基因与 SIOS 耐受性和 METO 丰度显著相关。此外，我们验证了柠檬酸合酶、葡萄糖基转移酶和细胞色素 P450 是基因型-METO-SIOS 耐受性关联的基础，并且表明它们的有利等位基因可以累加性地提高优良玉米自交系的 SIOS 耐受性。我们的研究为玉米 SIOS 耐受性的自然变异提供了新的见解，促进了玉米耐盐性的遗传改良，并展示了一种基于代谢组学的方法，用于挖掘与这种复杂农艺性状相关的作物基因。
