Doddaraju Pushpa, Dharmappa Prathibha M, Thiagarayaselvam Aarthy, Vijayaraghavareddy Preethi, Bheemanahalli Raju, Basavaraddi Priyanka A, Malagondanahalli Mohan Kumar V, Kambalimath Sumanth, Thulasiram Hirekodathakallu V, Sreeman Sheshshayee M
Department of Crop Physiology, University of Agricultural Sciences, Bengaluru, India.
ICAR-Indian Institute of Horticulture Research, Bengaluru, India.
Physiol Plant. 2023 May-Jun;175(3):e13917. doi: 10.1111/ppl.13917.
Mild stresses induce "acquired tolerance traits" (ATTs) that provide tolerance when stress becomes severe. Here, we identified the genetic variability in ATTs among a panel of rice germplasm accessions and demonstrated their relevance in protecting growth and productivity under water-limited conditions. Diverse approaches, including physiological screens, association mapping and metabolomics, were adopted and revealed 43 significant marker-trait associations. Nontargeted metabolomic profiling of contrasting genotypes revealed 26 "tolerance-related-induced" primary and secondary metabolites in the tolerant genotypes (AC-39000 and AC-39020) compared to the susceptible one (BPT-5204) under water-limited condition. Metabolites that help maintain cellular functions, especially Calvin cycle processes, significantly accumulated more in tolerant genotypes, which resulted in superior photosynthetic capacity and hence water use efficiency. Upregulation of the glutathione cycle intermediates explains the ROS homeostasis among the tolerant genotypes, maintaining spikelet fertility, and grain yield under stress. Bioinformatic dissection of a major effect quantitative trait locus on chromosome 8 revealed genes controlling metabolic pathways leading to the production of osmolites and antioxidants, such as GABA and raffinose. The study also led to the identification of specific trait donor genotypes that can be effectively used in translational crop improvement activities.
轻度胁迫会诱导“获得性耐受性状”（ATTs），当胁迫变得严重时，这些性状可提供耐受性。在此，我们鉴定了一组水稻种质资源中ATTs的遗传变异性，并证明了它们在水分受限条件下保护生长和生产力方面的相关性。我们采用了多种方法，包括生理筛选、关联作图和代谢组学，揭示了43个显著的标记-性状关联。对对比基因型进行的非靶向代谢组学分析显示，在水分受限条件下，与敏感基因型（BPT-5204）相比，耐受基因型（AC-39000和AC-39020）中有26种“耐受相关诱导”的初级和次级代谢产物。有助于维持细胞功能，尤其是卡尔文循环过程的代谢产物，在耐受基因型中显著积累更多，这导致了更高的光合能力，从而提高了水分利用效率。谷胱甘肽循环中间体的上调解释了耐受基因型中的活性氧稳态，维持了胁迫下的小穗育性和籽粒产量。对8号染色体上一个主要效应数量性状位点的生物信息学剖析揭示了控制导致渗透调节剂和抗氧化剂（如γ-氨基丁酸和棉子糖）产生的代谢途径的基因。该研究还鉴定出了可有效用于转化作物改良活动的特定性状供体基因型。
