薛耀威 陈丽兰 王亚如 高三基 王锦达

摘  要：丙二烯氧化物环化酶（allene oxide cyclase，AOC）是茉莉酸合成途径的一个关键酶，在植物防御反应中起着重要的作用。本研究基于甘蔗转录组数据库克隆到一个AOC基因，命名为ScAOC，并对其进行生物学分析、组织特异性分析和逆境胁迫下的表达分析，以初步了解该基因的功能。甘蔗ScAOC基因的开放阅读框（ORF）为744 bp，编码244个氨基酸，其蛋白分子质量是26.37 kDa。生物信息学分析结果显示，ScAOC蛋白属于不稳定碱性亲水蛋白，含有1个Allene_ox_cyc Superfamily的PLN02343 domain的保守结构域;构建系统进化树，结果显示ScAOC蛋白与高粱的蛋白具有较高的同源性。荧光定量PCR结果显示，ScAOC基因在甘蔗的根、茎、叶中均有表达，表达量从高到低依次是叶、根、茎。在PEG、NaCl及外源MeJA胁迫下，ScAOC基因相对表达量都是先上升后下降，而ABA对ScAOC的表达有一定的抑制作用。在病原菌和粘虫取食的胁迫下，ScAOC基因相对表达量显著上升。结果显示ScAOC可能参与甘蔗对生物或非生物胁迫的防御反应。

关键词：甘蔗;丙二烯氧化物环化酶;茉莉酸;生物信息学分析

中图分类号：S566.1      文献标识码：A

Abstract： Allene oxide cyclase （AOC） is a key enzyme in the synthesis pathway of jasmonic acid and plays an important role in plant defense reactions. In this study， an AOC gene was cloned based on the sugarcane transcriptome database and named ScAOC. Biological analysis， tissue-specific analysis， and expression analysis under stress were conducted to understand the preliminary function of the gene. The open reading frame （ORF） of the ScAOC gene in sugarcane was 744 bp， encoding 244 amino acids， and its protein molecular mass was 26.37 kDa. Bioinformatics analysis showed that the ScAOC protein was an unstable basic hydrophilic protein and contained a conserved domain of the PLN02343 domain of Allene_ox_cyc Superfamily. Constructing a phylogenetic tree showed that the ScAOC protein has a high homology with sorghum protein. Fluorescence quantitative PCR showed that the ScAOC gene was expressed in the roots， stems and leaves of sugarcane， and the expression levels from high to low were leaves， roots and stems. Under the stress of PEG， NaCl and exogenous MeJA， the relative expression of ScAOC gene increased first and then decreased， and ABA had a certain inhibitory effect on the expression of ScAOC. Under the stress of pathogenic bacteria and armyworm feeding， the relative expression of ScAOC gene increased significantly. The results showed that ScAOC maight be involved in the defense response of sugarcane to biological or abiotic stress.

Keywords： sugarcane; allene oxide cyclase; jasmonic acid; bioinformatics analysis

DOI： 10.3969/j.issn.1000-2561.2021.05.007

甘蔗是我國最主要的糖料作物，甘蔗产糖占我国食糖总量的90%左右[1]，此外甘蔗也是重要潜在的能源作物，因此甘蔗的优质高效生产是事关国计民生的大事。甘蔗属于多年生作物，生产周期较长，且长期连作，经常受到各种不良环境的威胁，导致甘蔗产量降低，蔗汁品质下降。而目前田间管理上多通过喷施化学肥料和农药的方法，提高甘蔗抵御外界各种胁迫。……