Nie Qiong, Gao Guo-Li, Fan Qing-jie, Qiao Guang, Wen Xiao-Peng, Liu Tao, Peng Zhi-Jun, Cai Yong-Qiang
Key Laboratory of Plant Resources Conservation and Germplasm Innovation in Mountainous Region (Guizhou University), Ministry of Education, Institute of Agro-bioengineering, Guizhou University, Guiyang 550025, Guizhou Province, PR China; College of Agriculture, Guizhou University, Guiyang 550025, Guizhou Province, PR China.
Key Laboratory of Plant Resources Conservation and Germplasm Innovation in Mountainous Region (Guizhou University), Ministry of Education, Institute of Agro-bioengineering, Guizhou University, Guiyang 550025, Guizhou Province, PR China.
Gene. 2015 May 25;563(1):63-71. doi: 10.1016/j.gene.2015.03.007. Epub 2015 Mar 6.
Abiotic stresses usually cause H2O2 accumulation, with harmful effects, in plants. Catalase may play a key protective role in plant cells by detoxifying this excess H2O2. Pitaya (Hylocereus undatus) shows broad ecological adaptation due to its high tolerance to abiotic stresses, e.g. drought, heat and poor soil. However, involvement of the pitaya catalase gene (HuCAT) in tolerance to abiotic stresses is unknown. In the present study, a full-length HuCAT3 cDNA (1870 bp) was isolated from pitaya based on our previous microarray data and RACE method. The cDNA sequence and deduced amino acid sequence shared 73-77% and 75-80% identity with other plant catalases, respectively. HuCAT3 contains conserved catalase family domain and catalytic sites. Pairwise comparison and phylogenetic analysis indicated that HuCAT3 is most similar to Eriobotrya japonica CAT, followed by Dimocarpus longan CAT and Nicotiana tabacum CAT1. Expression profile analysis demonstrated that HuCAT3 is mainly expressed in green cotyledons and mature stems, and was regulated by H2O2, drought, cold and salt stress, whereas, its expression patterns and maximum expression levels varied with stress types. HuCAT activity increased as exposure to the tested stresses, and the fluctuation of HuCAT activity was consistent with HuCAT3 mRNA abundance (except for 0.5 days upon drought stress). HuCAT3 mRNA elevations and HuCAT activities changes under cold stress were also in conformity with the cold tolerances among the four genotypes. The obtained results confirmed a major role of HuCAT3 in abiotic stress response of pitaya. This may prove useful in understanding pitaya's high tolerance to abiotic stresses at molecular level.
非生物胁迫通常会导致植物体内积累具有有害作用的过氧化氢。过氧化氢酶可能通过清除过量的过氧化氢在植物细胞中发挥关键的保护作用。火龙果（Hylocereus undatus）因其对干旱、高温和土壤贫瘠等非生物胁迫具有高度耐受性而表现出广泛的生态适应性。然而，火龙果过氧化氢酶基因（HuCAT）在非生物胁迫耐受性中的作用尚不清楚。在本研究中，基于我们之前的微阵列数据和RACE方法，从火龙果中分离出了一个全长HuCAT3 cDNA（1870 bp）。该cDNA序列和推导的氨基酸序列与其他植物过氧化氢酶的一致性分别为73 - 77%和75 - 80%。HuCAT3包含保守的过氧化氢酶家族结构域和催化位点。成对比较和系统发育分析表明，HuCAT3与枇杷CAT最为相似，其次是龙眼CAT和烟草CAT1。表达谱分析表明，HuCAT3主要在绿色子叶和成熟茎中表达，并受过氧化氢、干旱、寒冷和盐胁迫的调控，但其表达模式和最大表达水平因胁迫类型而异。随着暴露于测试胁迫，HuCAT活性增加，并且HuCAT活性的波动与HuCAT3 mRNA丰度一致（干旱胁迫0.5天时除外）。冷胁迫下HuCAT3 mRNA的升高和HuCAT活性的变化也与四种基因型之间的耐寒性一致。所得结果证实了HuCAT3在火龙果非生物胁迫响应中的主要作用。这可能有助于在分子水平上理解火龙果对非生物胁迫的高度耐受性。
