Wang Xu-Chu, Li Qin, Jin Xiang, Xiao Guang-Hui, Liu Gao-Jun, Liu Nin-Jing, Qin Yong-Mei
The State Key Laboratory of Protein and Plant Gene Research, College of Life Sciences, Peking University, Beijing, 100871, China; Key Laboratory of Biology and Genetic Resources for Tropical Crops, Institute of Tropical Biosciences and Biotechnology, Chinese Academy of Tropical Agricultural Sciences, Haikou, Hainan 571101, China.
The State Key Laboratory of Protein and Plant Gene Research, College of Life Sciences, Peking University, Beijing, 100871, China.
J Proteomics. 2015 Jan 30;114:16-27. doi: 10.1016/j.jprot.2014.10.022. Epub 2014 Nov 8.
An iTRAQ-based proteomics of ovules from the upland cotton species Gossypium hirsutum and its fuzzless-lintless mutant was performed, and finally 2729 proteins that preferentially accumulated at anthesis in wild-type ovules were identified. We confirmed that the gene expression levels of 2005 among these proteins also increased by performing an RNA sequencing transcriptomics. Expression of proteins involved in carboxylic acid metabolism, small-molecule metabolic processes, hormone regulation, and lipid metabolism was significantly enhanced in wild-type ovules. Quantitative real-time PCR verified the increased expression of 26 genes involved in these processes. Cotton 3-hydroxyacyl-CoA dehydratase (GhPAS2) catalyzing the third reaction of very long-chain fatty acid (VLCFA) biosynthesis, accumulated at anthesis in wild-type ovules. Heterogeneous expression of GhPAS2 restored viability to the Saccharomyces cerevisiae haploid psh1-deletion strain deficient in PAS2 activity. Application of VLCFA biosynthesis inhibitor acetochlor (2-chloro-N-[ethoxymethyl]-N-[2-ethyl-6-methyl-phenyl]-acetamide; ACE) and gibberellic acid to the unfertilized cotton ovules significantly suppressed fiber cell protrusion. In this study, the profiling of gene expression at both transcriptome and proteome levels provides new insights into cotton fiber cell initiation.
Cotton fiber initiation determines the ultimate number of fibers per ovule, thereby determining fiber yield. In total, 2729 proteins were preferentially accumulated in wild-type ovules at anthesis. The most up-regulated proteins were assigned to carboxylic acid metabolism, small-molecule metabolic processes, hormone regulation, and lipid metabolism. In consistence with these findings, we characterized GhPAS2 gene coding for the enzyme that catalyzes VLCFA production. VLCFA biosynthesis inhibitor, acetochlor, was shown to significantly suppress fiber initiation. This study provides a genome-scale transcriptomic and proteomic characterization of fiber initial cells, laying a solid basis for further investigation of the molecular processes governing fiber cell development.
对陆地棉品种陆地棉及其无绒无絮突变体的胚珠进行了基于iTRAQ的蛋白质组学分析，最终鉴定出2729种在野生型胚珠开花期优先积累的蛋白质。通过RNA测序转录组学分析，我们证实了这些蛋白质中2005种的基因表达水平也有所增加。参与羧酸代谢、小分子代谢过程、激素调节和脂质代谢的蛋白质在野生型胚珠中的表达显著增强。定量实时PCR验证了参与这些过程的26个基因的表达增加。催化超长链脂肪酸（VLCFA）生物合成第三步反应的棉花3-羟酰基辅酶A脱水酶（GhPAS2）在野生型胚珠开花期积累。GhPAS2的异源表达恢复了缺乏PAS2活性 的酿酒酵母单倍体psh1缺失菌株的活力。将VLCFA生物合成抑制剂乙草胺（2-氯-N-[乙氧基甲基]-N-[2-乙基-6-甲基苯基]-乙酰胺；ACE）和赤霉素应用于未受精的棉花胚珠，显著抑制了纤维细胞的突出。在本研究中，转录组和蛋白质组水平的基因表达谱为棉花纤维细胞起始提供了新的见解。
棉花纤维起始决定了每个胚珠最终的纤维数量，从而决定了纤维产量。总共有2729种蛋白质在野生型胚珠开花期优先积累。上调最多的蛋白质与羧酸代谢、小分子代谢过程、激素调节和脂质代谢有关。与这些发现一致，我们对编码催化VLCFA产生的酶的GhPAS2基因进行了表征。VLCFA生物合成抑制剂乙草胺被证明能显著抑制纤维起始。本研究提供了纤维起始细胞的基因组规模转录组学和蛋白质组学特征，为进一步研究控制纤维细胞发育的分子过程奠定了坚实基础。
