Rubber Research Institute & Key Laboratory of Biology and Genetic Resources of Rubber Trees, Ministry of Agriculture of China, Chinese Academy of Tropical Agricultural Sciences, Danzhou, Hainan, 571737, China.
College of Agriculture, Hainan University, Haikou, 570228, China.
BMC Genomics. 2018 Jan 2;19(1):5. doi: 10.1186/s12864-017-4419-6.
Acyl-CoA-binding proteins (ACBPs) are mainly involved in acyl-CoA ester binding and trafficking in eukaryotic cells, and their various functions have been characterized in model plants, such as Arabidopsis thaliana (A. thaliana), Oryza sativa (rice), and other plant species. In the present study, genome-wide mining and expression analysis of ACBP genes was performed on Hevea brasiliensis (the para rubber tree), the most important latex-producing crop in the world.
Six members of the H. brasiliensis ACBP family genes, designated HbACBP1-HbACBP6, were identified from the H. brasiliensis genome. They can be categorized into four classes with different amino acid sequences and domain structures based on the categorization of their A. thaliana counterparts. Phylogenetic analysis shows that the HbACBPs were clustered with those of other closely related species, such as Manihot esculenta, Ricinus communis, and Jatropha carcas, but were further from those of A. thaliana, a distantly related species. Expression analysis demonstrated that the HbACBP1 and HbACBP2 genes are more prominently expressed in H. brasiliensis latex, and their expression can be significantly enhanced by bark tapping (a mechanical wound) and jasmonic acid stimulation, whereas HbACBP3-HbACBP6 had almost the same expression patterns with relatively high levels in mature leaves and male flowers, but a markedly low abundance in the latex. HbACBP1 and HbACBP2 may have crucial roles in lipid and latex metabolism in laticifers, so their subcellular location was further investigated and the results indicated that HbACBP1 is a cytosol protein, whereas HbACBP2 is an endoplasmic reticulum-associated ACBP.
In this study, the H. brasiliensis ACBP family genes were identified. Phylogenetic analyses of the HbABCPs indicate that there is a high conservation and evolutionary relationship between ACBPs in land plants. The HbACBPs are organ/tissue-specifically expressed and have different expression patterns in response to stimulation by bark tapping or ethrel/jasmonic acid. HbACBP1 and HbACBP2 are two important latex ACBPs that might be involved in the lipid and latex metabolism. The results may provide valuable information for further investigations into the biological functions of HbACBPs during latex metabolism and stress responses in H. brasiliensis.
酰基辅酶 A 结合蛋白（ACBPs）主要参与真核细胞中酰基辅酶 A 酯的结合和运输，其各种功能已在模式植物如拟南芥（Arabidopsis thaliana，A. thaliana）、水稻（Oryza sativa）和其他植物物种中得到了描述。本研究在世界上最重要的产胶作物巴西橡胶树（Hevea brasiliensis）中进行了 ACBP 基因的全基因组挖掘和表达分析。
从巴西橡胶树基因组中鉴定出 6 个巴西橡胶树 ACBP 家族基因，分别命名为 HbACBP1-HbACBP6。根据与拟南芥同源物的分类，它们可以分为具有不同氨基酸序列和结构域的四个类。系统发育分析表明，HbACBPs 与亲缘关系较近的物种，如 Manihot esculenta、Ricinus communis 和 Jatropha carcas 聚类，但与亲缘关系较远的物种拟南芥聚类较远。表达分析表明，HbACBP1 和 HbACBP2 基因在巴西橡胶树乳胶中表达更为显著，树皮敲击（机械损伤）和茉莉酸刺激可显著增强其表达，而 HbACBP3-HbACBP6 在成熟叶片和雄花中具有几乎相同的表达模式，但在乳胶中表达水平较低。HbACBP1 和 HbACBP2 可能在乳管的脂质和乳胶代谢中起关键作用，因此进一步研究了它们的亚细胞定位，结果表明 HbACBP1 是细胞质蛋白，而 HbACBP2 是内质网相关的 ACBP。
本研究鉴定了巴西橡胶树 ACBP 家族基因。HbABCPs 的系统发育分析表明，陆地植物的 ACBPs 具有高度的保守性和进化关系。HbACBPs 是器官/组织特异性表达的，并且对树皮敲击或乙烯利/茉莉酸的刺激有不同的表达模式。HbACBP1 和 HbACBP2 是两种重要的乳胶 ACBP，可能参与脂质和乳胶代谢。研究结果可为进一步研究巴西橡胶树乳胶代谢和应激响应过程中 HbACBPs 的生物学功能提供有价值的信息。
