Hong Ye, Ni Sheng-Jing, Zhang Guo-Ping
Agronomy Department, Zhejiang Key Lab of Crop Germplasm, Zhejiang University, Hangzhou, 310058, China.
Agronomy Department, Zhejiang Key Lab of Crop Germplasm, Zhejiang University, Hangzhou, 310058, China.
Plant Physiol Biochem. 2020 Apr 25;152:1-11. doi: 10.1016/j.plaphy.2020.04.029.
Malting quality will be greatly deteriorated when barley plants suffer from post-anthesis drought stress, however there is a marked difference among barley genotypes in the responses of malting quality to drought stress, and the molecular mechanisms underlying the genotypic difference remain unclear. We made transcriptome and metabolome analysis on the developing grains of two barley genotypes differing in the responses to drought stress. Post-anthesis drought treatments led to decreased grain weight and β-glucan content, increased grain protein content and β-amylase activity. Drought stress enhanced HO and heat-shock protein accumulation in the two barley genotypes, with the drought-tolerant genotype showing higher capacity of scavenging HO and reducing misfolded protein accumulation than the drought-susceptible genotype. Moreover, the drought-tolerant genotype was more efficient in redistributing assimilates stored in the vegetative tissues into the developing grains. After re-watering to relieve drought stress, the drought-tolerant genotype can further modify auxin transport and ethylene signaling, enhancing redistribution of assimilates into grains. Transcriptome comparisons and weighted correlation network analysis (WGCNA) identified some key genes regulating the responses of malting quality traits to drought stress, such as RLK-LRR, β-glucosidase and HSP . In conclusion, less change of main malting quality traits in the drought-tolerant genotype under post-anthesis drought stress is attributed to its higher capacity of alleviating the stress injury through scavenging ROS and redistributing the metabolites stored in the vegetative organs into the developing grains.
大麦植株在花后遭受干旱胁迫时，麦芽品质会大幅下降，然而不同大麦基因型在麦芽品质对干旱胁迫的响应方面存在显著差异，且基因型差异背后的分子机制仍不清楚。我们对两种在干旱胁迫响应上存在差异的大麦基因型的发育籽粒进行了转录组和代谢组分析。花后干旱处理导致粒重和β-葡聚糖含量降低，籽粒蛋白质含量和β-淀粉酶活性增加。干旱胁迫增强了两种大麦基因型中羟基自由基（HO）和热休克蛋白的积累，耐旱基因型清除HO和减少错误折叠蛋白积累的能力高于干旱敏感基因型。此外，耐旱基因型在将营养组织中储存的同化物重新分配到发育中的籽粒方面更有效。在重新浇水以缓解干旱胁迫后，耐旱基因型能够进一步调节生长素运输和乙烯信号传导，增强同化物向籽粒的重新分配。转录组比较和加权基因共表达网络分析（WGCNA）确定了一些调节麦芽品质性状对干旱胁迫响应的关键基因，如富含亮氨酸重复序列的类受体蛋白激酶（RLK-LRR）、β-葡萄糖苷酶和热休克蛋白（HSP）。总之，耐旱基因型在花后干旱胁迫下主要麦芽品质性状变化较小，这归因于其通过清除活性氧和将营养器官中储存的代谢物重新分配到发育中的籽粒来减轻胁迫伤害具有更高的能力。
