植物表皮蜡质合成、运输及调控机制研究进展

Research progress on genetic mechanisms of plant epidermal wax synthesis,transport and regulation

为阐明植物蜡质合成/转运的分子机制及调控网络,依据PubMed,WebofScience和中国知网数据库,以“表皮蜡质”和“植物”的中英文为关键词,检索了1974—2022年发表的相关文献125篇,通过整理和归纳,分析以玉米为代表的植物蜡质代谢相关合成,转运及调控网络。结果表明:植物蜡质成分复杂,一般由超长链脂肪酸、烷烃、醛、醇、酮以及萜类和一些小分子次级代谢物组成。且不同植物及同一种植物不同器官蜡质含量及成分均不同。模式植物拟南芥中表皮蜡质合成、运输及调控机理研究相对清楚,植物蜡质前体物质超长链脂肪酸(verylong chainfattyacids,VLCFAs)在脂肪酰-CoA延长酶等多酶体系催化下合成,包括β-酮脂酰-CoA合酶、β-酮脂酰-CoA还原酶、β-羟脂酰-CoA脱水酶和反式烯脂酰-CoA还原酶组成,合成后的VLCFAs通过脱羰基与酰基还原作用进入角质层蜡质合成途径,形成各种蜡质组分。单子叶植物蜡质合成及排列方式与双子叶植物有很多相似之处,也有一定差异,如,拟南芥中ABCG32编码的脂质转运蛋白参与莲座叶角质层蜡质的形成,而玉米GLOSSY13、大麦的HvABCG31和水稻的OsABCG31主要是在幼叶表皮蜡质转运过程起作用。目前,玉米中发现的蜡质突变体超过了30多个,相关基因还有待挖掘。

In order to elucidate the molecular mechanism and regulatory network of plant wax synthesis and transport,125 articles published from 1974 to 2022 were retrieved based on PubMed,Web of Science and China National Knowledge Infrastructure by using both Chinese and English keywords“epidermal wax”and“plant”.The metabolisms of the synthesis,transport and regulation networks of wax in maize were summarized.The results show that:Plant wax is composed of long chain fatty acids,alkanes,aldehydes,alcohols,ketones,terpenes and some small molecular secondary metabolites.The content and composition of wax are different in different plants and in different organs even in same plant.The synthesis,transport and regulation mechanism of epidermal waxy acids in model plant Arabidopsis thaliana are relatively clear.The very long chain fatty acids(VLCFAs)were synthesized by fatty acyl-CoA elongase multienzyme system.The synthesized VLCFAs were composed ofβ-ketoacyl-CoA synthase,β-ketoacyl-CoA reductase,β-hydroxyl-CoA dehydrase and trans-oleyl-CoA reductase.The synthesized VLCFAs participate the corneous wax synthesis pathway through decarbonylation and acyl reduction,and formed various waxy components.The wax synthesis and arrangement in monocotyledon plants are similar to dicotyledon plants and different in some aspect.For example,the lipid transporter ABCG32 in A.thaliana involves in the rosette leaf cuticle wax loading,while its homolog GLOSSY13 plays a role in the wax transport in young leaf epidermis in maize.HvABCG31 and OsABCG31 are the two homologos of GLOSSY13 and AtABCG32 in barley and rice,respectively and mainly function in young leaves.More than 30 waxy mutants were found in maize,and the related genes are still to be discovered.