Morton Kyla J, Jia Shangang, Zhang Chi, Holding David R
Department of Agronomy and Horticulture, Center for Plant Science Innovation, Beadle Center for Biotechnology, 1901 Vine Street, PO Box 880665, University of Nebraska, Lincoln, NE 68588-0665, USA.
School of Biological Sciences, Center for Plant Science Innovation, Beadle Center for Biotechnology, 1901 Vine Street, PO Box 880665, University of Nebraska, Lincoln, NE 68588-0665, USA.
J Exp Bot. 2016 Mar;67(5):1381-96. doi: 10.1093/jxb/erv532. Epub 2015 Dec 27.
Reduced prolamin (zein) accumulation and defective endoplasmic reticulum (ER) body formation occurs in maize opaque endosperm mutants opaque2 (o2), floury2 (fl2), defective endosperm*B30 (DeB30), and Mucronate (Mc), whereas other opaque mutants such as opaque1 (o1) and floury1 (fl1) are normal in these regards. This suggests that other factors contribute to kernel texture. A liquid chromatography approach coupled with tandem mass spectrometry (LC-MS/MS) proteomics was used to compare non-zein proteins of nearly isogenic opaque endosperm mutants. In total, 2762 proteins were identified that were enriched for biological processes such as protein transport and folding, amino acid biosynthesis, and proteolysis. Principal component analysis and pathway enrichment suggested that the mutants partitioned into three groups: (i) Mc, DeB30, fl2 and o2; (ii) o1; and (iii) fl1. Indicator species analysis revealed mutant-specific proteins, and highlighted ER secretory pathway components that were enriched in selected groups of mutants. The most significantly changed proteins were related to stress or defense and zein partitioning into the soluble fraction for Mc, DeB30, o1, and fl1 specifically. In silico dissection of the most significantly changed proteins revealed novel qualitative changes in lysine abundance contributing to the overall lysine increase and the nutritional rebalancing of the o2 and fl2 endosperm.
在玉米不透明胚乳突变体不透明2（o2）、粉质2（fl2）、胚乳缺陷*B30（DeB30）和具短尖（Mc）中，醇溶蛋白（玉米醇溶蛋白）积累减少且内质网（ER）体形成有缺陷，而其他不透明突变体如不透明1（o1）和粉质1（fl1）在这些方面是正常的。这表明还有其他因素影响籽粒质地。采用液相色谱与串联质谱（LC-MS/MS）蛋白质组学方法比较近等基因不透明胚乳突变体的非醇溶蛋白。总共鉴定出2762种蛋白质，这些蛋白质在蛋白质转运与折叠、氨基酸生物合成和蛋白水解等生物学过程中富集。主成分分析和通路富集表明，突变体分为三组：（i）Mc、DeB30、fl2和o2；（ii）o1；（iii）fl1。指示物种分析揭示了突变体特异性蛋白质，并突出了在特定突变体组中富集的ER分泌途径成分。变化最显著的蛋白质与胁迫或防御相关，并且对于Mc、DeB30、o1和fl1而言，玉米醇溶蛋白特异性地分配到可溶部分。对变化最显著的蛋白质进行计算机分析揭示了赖氨酸丰度的新定性变化，这有助于o2和fl2胚乳中赖氨酸总量的增加和营养再平衡。
