Division of Biological Sciences and Interdisciplinary Plant Group, University of Missouri, Columbia, Missouri 65211, USA.
U.S. Department of Agriculture-Agricultural Research Service, Columbia, Missouri 65211, USA.
Plant Physiol. 2022 Jan 20;188(1):111-133. doi: 10.1093/plphys/kiab390.
Maize (Zea mays) seeds are a good source of protein, despite being deficient in several essential amino acids. However, eliminating the highly abundant but poorly balanced seed storage proteins has revealed that the regulation of seed amino acids is complex and does not rely on only a handful of proteins. In this study, we used two complementary omics-based approaches to shed light on the genes and biological processes that underlie the regulation of seed amino acid composition. We first conducted a genome-wide association study to identify candidate genes involved in the natural variation of seed protein-bound amino acids. We then used weighted gene correlation network analysis to associate protein expression with seed amino acid composition dynamics during kernel development and maturation. We found that almost half of the proteome was significantly reduced during kernel development and maturation, including several translational machinery components such as ribosomal proteins, which strongly suggests translational reprogramming. The reduction was significantly associated with a decrease in several amino acids, including lysine and methionine, pointing to their role in shaping the seed amino acid composition. When we compared the candidate gene lists generated from both approaches, we found a nonrandom overlap of 80 genes. A functional analysis of these genes showed a tight interconnected cluster dominated by translational machinery genes, especially ribosomal proteins, further supporting the role of translation dynamics in shaping seed amino acid composition. These findings strongly suggest that seed biofortification strategies that target the translation machinery dynamics should be considered and explored further.
玉米（Zea mays）种子是蛋白质的良好来源，尽管它们缺乏几种必需氨基酸。然而，消除高度丰富但平衡不良的种子贮藏蛋白表明，种子氨基酸的调节是复杂的，并不依赖于少数几种蛋白质。在这项研究中，我们使用了两种互补的基于组学的方法来阐明调节种子氨基酸组成的基因和生物学过程。我们首先进行了全基因组关联研究，以鉴定参与种子蛋白结合氨基酸自然变异的候选基因。然后，我们使用加权基因相关网络分析将蛋白质表达与核仁发育和成熟过程中种子氨基酸组成的动态变化联系起来。我们发现，几乎一半的蛋白质组在核仁发育和成熟过程中显著减少，包括核糖体蛋白等几个翻译机制成分，这强烈表明了翻译的重新编程。这种减少与几种氨基酸的减少密切相关，包括赖氨酸和蛋氨酸，这表明它们在塑造种子氨基酸组成方面的作用。当我们比较这两种方法生成的候选基因列表时，我们发现有 80 个基因存在非随机重叠。对这些基因的功能分析表明，一个紧密相互关联的簇占主导地位，主要是翻译机制基因，尤其是核糖体蛋白，这进一步支持了翻译动态在塑造种子氨基酸组成方面的作用。这些发现强烈表明，应该考虑并进一步探索针对翻译机制动态的种子生物强化策略。
