王江英 朱朋波 葛金涛 惠林冲 李纪元 孙明伟 赵统利 邵小斌 汤雪燕

摘  要：根据山茶（Camellia japonica）同源序列设计特异性引物，利用同源克隆和3，5-RACE技术，从杜鹃红山茶（C. azalea）花芽组织中克隆出ACC氧化酶（ACC-oxidase， ACO）基因，命名为CaACO1，基因全长1232 bp，开放阅读框963 bp，编码320个氨基酸。实时荧光定量PCR分析发现，ACO1在杜鹃红山茶不同组织中均得到表达，其中茎尖ACO1表达量最低，其次花芽、叶芽、根尖，表达量较高的是真叶和花器官，随着叶片成熟和花器官发育ACO1表达量均逐渐增加。结果表明，该基因可能参与杜鹃红山茶叶片发育，并且与花器官衰老密切相关。ACO1在参试的8个山茶品种花器官发育过程中的表达模式基本一致，但不同品种间的表达量存在差异。相关性分析发现ACO1表达量与花型、花色、花径和花瓣数4个形态指标均无显著相关性。

关键词：山茶;ACC氧化酶;基因克隆;表达分析;形态指标

Abstract： On the basic of homologous sequences of Camellia japonica， an ACC-oxidase （ACO） gene was cloned from the floral bud of C. azalea by the 3，5-RACE technology named CaACO1. The full-length cDNA of CaACO1 was 1232 bp， containing a 963 bp ORF which encoding 320 amino acids. Expression of ACO1 in the four development periods of the floral organ in C. azalea were analyzed by fluorescent quantitative real-time PCR. ACO1 was expressed in twelve samples differently， where the expression level of ACO1 in shoot tip was the lowest， medium in flower bud， leaf bud and root tip， the highest in true leaves and flower， which indicated that ACO1 may be involved in the leaf development of C. azalea and associated with flower senescence. The trends of expressions of ACO1 were almost the same as in the four development periods of the eight camellias， but the expression levels were different. Correlation analysis found that the expression of ACO1 was not significantly correlated with four morphological indexes of flower type， flower color， flower diameter and petal number.

Keywords： Camellia japonica; ACC-oxidase; gene clone; expression analysis; flower organ characteristics

山茶（Camellia japonica）树形优美，叶色浓绿，花形多样，色彩丰富，花期较长，从10月到翌年5月都有开放，盛花期1—3月，具有极高的观赏价值[1]。近年来新发现的杜鹃红山茶（C. azalea）是山茶属中能够四季开花的奇特原种，是中国独有的宝贵山茶种质资源[2]。然而单朵花开放时间因不同山茶品种存在差异，但盛花期7～ 10 d后花朵均衰老败落。通过分子生物学技术研究花器官发育相关基因可为花期延长提供依据。

乙烯是植物衰老的主要调控因子，参与植物的种子萌发、生根、茎叶生长、花芽分化以及叶片和花器官衰老等不同的生理发育过程[3-4]。ACC氧化酶（ACO）是乙烯生物合成途径中的最后一个酶，抑制ACO活性可以降低乙烯生成，从而延缓切花衰老和提高盆花品质[5-6]。……