Key Laboratory of Crop Genetics and Physiology of Jiangsu Province, Key Laboratory of Plant Functional Genomics of the Ministry of Education, Jiangsu Key Laboratory of Crop Genomics and Molecular Breeding, College of Agriculture, Yangzhou University, Yangzhou, 225009, China; Co-Innovation Center for Modern Production Technology of Grain Crops of Jiangsu Province, Joint International Research Laboratory of Agriculture and Agri-Product Safety of the Ministry of Education, Yangzhou University, Yangzhou, 225009, China.
Key Laboratory of Crop Genetics and Physiology of Jiangsu Province, Key Laboratory of Plant Functional Genomics of the Ministry of Education, Jiangsu Key Laboratory of Crop Genomics and Molecular Breeding, College of Agriculture, Yangzhou University, Yangzhou, 225009, China.
Plant Sci. 2020 Apr;293:110435. doi: 10.1016/j.plantsci.2020.110435. Epub 2020 Feb 4.
Seed germination is essential for ensuring grain yield and quality. Germination rate, uniformity, and post-germination growth all contribute to cultivation. Although the phytohormones gibberellin (GA) and brassinosteroid (BR) are known to regulate germination, the underlying mechanism of their crosstalk in co-regulating rice seed germination remains unclear. In this study, the isobaric tags for relative and absolute quantitation (iTRAQ) proteomic approach was employed to identify target proteins responsive to GA during recovery of germination in BR-deficient and BR-insensitive rice. A total of 42 differentially abundant proteins were identified in both BR-deficient and BR-insensitive plants, and most were altered consistently in the two groups. Gene Ontology (GO) analysis revealed enrichment in proteins with binding and catalytic activity. A potential protein-protein interaction network was constructed using STRING analysis, and five Late Embryogenesis Abundant (LEA) family members were markedly down-regulated at both mRNA transcript and protein levels. These LEA genes were specifically expressed in rice seeds, especially during the latter stages of seed development. Mutation of LEA33 affected rice grain size and seed germination, possibly by reducing BR accumulation and enhancing GA biosynthesis. The findings improve our knowledge of the mechanisms by which GA and BR coordinate seed germination.
种子萌发对于确保谷物的产量和质量至关重要。萌发率、一致性和萌发后的生长都有助于栽培。尽管植物激素赤霉素（GA）和油菜素内酯（BR）被认为可以调节萌发，但它们在共同调节水稻种子萌发中的相互作用的潜在机制仍不清楚。在这项研究中，采用同位素相对和绝对定量（iTRAQ）蛋白质组学方法来鉴定在 BR 缺陷和 BR 不敏感的水稻恢复萌发过程中对 GA 有响应的靶蛋白。在 BR 缺陷和 BR 不敏感的植物中总共鉴定出 42 个差异丰度蛋白，并且大多数在两组中都一致改变。GO 分析显示富含具有结合和催化活性的蛋白。使用 STRING 分析构建了一个潜在的蛋白质-蛋白质相互作用网络，并且五个晚期胚胎丰富（LEA）家族成员在 mRNA 转录本和蛋白质水平上都明显下调。这些 LEA 基因特异性地在水稻种子中表达，特别是在种子发育的后期阶段。LEA33 的突变影响水稻籽粒大小和种子萌发，可能是通过降低 BR 积累和增强 GA 生物合成来实现的。这些发现提高了我们对 GA 和 BR 协调种子萌发的机制的认识。
