School of Plant Sciences, University of Arizona, Tucson, AZ, 85721, USA.
Plant Reprod. 2018 Sep;31(3):319-326. doi: 10.1007/s00497-018-0344-3. Epub 2018 Jul 5.
The endosperm of angiosperms is a zygotic seed organ that stores nutrient reserves to support embryogenesis and seed germination. Cereal endosperm is also a major source of human calories and an industrial feedstock. Maize opaque endosperm mutants commonly exhibit opaque, floury kernels, along with other abnormal seed and/or non-seed phenotypes. The opaque endosperm phenotype is sometimes accompanied by a soft kernel texture and increased nutritional quality, including a higher lysine content, which are valuable agronomic traits that have drawn attention of maize breeders. Recently, an increasing number of genes that underlie opaque mutants have been cloned, and their characterization has begun to shed light on the molecular basis of the opaque endosperm phenotype. These mutants are categorized by disruption of genes encoding zein or non-zein proteins localized to protein bodies, enzymes involved in endosperm metabolic processes, or transcriptional regulatory proteins associated with endosperm storage programs.
被子植物的胚乳是一种合子种子器官，它储存营养物质储备以支持胚胎发生和种子萌发。谷类胚乳也是人类卡路里的主要来源和工业原料。玉米不透明胚乳突变体通常表现出不透明、粉质的籽粒，以及其他异常的种子和/或非种子表型。不透明胚乳表型有时伴随着柔软的 kernel 质地和更高的营养品质，包括更高的赖氨酸含量，这些都是有价值的农艺性状，引起了玉米育种者的关注。最近，越来越多的不透明突变体所依赖的基因被克隆，它们的特征开始揭示不透明胚乳表型的分子基础。这些突变体是通过破坏编码位于蛋白体中的 zein 或非 zein 蛋白、参与胚乳代谢过程的酶、或与胚乳储存程序相关的转录调节蛋白的基因来分类的。
