Lin Fan, Zhang Yun, Jiang Ming-Yi
College of Life Sciences, Nanjing Agricultural University, Nanjing 210095, China.
J Integr Plant Biol. 2009 Mar;51(3):287-98. doi: 10.1111/j.1744-7909.2008.00808.x.
With the exception of rice, little is known about the existence of respiratory burst oxidase homolog (rboh) gene in cereals. The present study reports the cloning and analysis of a novel rboh gene, termed ZmrbohB, from maize (Zea mays L.). The full-length cDNA of ZmrbohB encodes a 942 amino acid protein containing all of the respiratory burst oxidase homolog catalytically critical motifs. Alternative splicing of ZmrbohB has generated two transcript isoforms, ZmrbohB-alpha and -beta. Spliced transcript ZmrbohB-beta retains an unspliced intron 11 that carries a premature termination codon and probably leads to nonsense-mediated mRNA decay. Expression analysis showed that two splice isoforms were differentially expressed in various tissues and at different developmental stages, and the major product was ZmrbohB-alpha. The transcripts of ZmrbohB-alpha accumulated markedly when the maize seedlings were subjected to various abiotic stimuli, such as wounding, cold (4 degrees C), heat (40 degrees C), UV and salinity stress. In addition, several abiotic stimuli also affected the alternative splicing pattern of ZmrbohB except wounding. These results provide new insight into roles in the expression regulation of plant rboh genes and suggest that ZmrbohB gene may play a role in response to environmental stresses.
除水稻外，人们对谷物中呼吸爆发氧化酶同源物（rboh）基因的存在知之甚少。本研究报道了从玉米（Zea mays L.）中克隆和分析一个新的rboh基因，命名为ZmrbohB。ZmrbohB的全长cDNA编码一个942个氨基酸的蛋白质，包含所有呼吸爆发氧化酶同源物的催化关键基序。ZmrbohB的可变剪接产生了两种转录异构体，ZmrbohB-α和-β。剪接后的转录本ZmrbohB-β保留了一个未剪接的内含子11，该内含子带有一个提前终止密码子，可能导致无义介导的mRNA降解。表达分析表明，两种剪接异构体在不同组织和不同发育阶段差异表达，主要产物是ZmrbohB-α。当玉米幼苗受到各种非生物刺激，如伤口、低温（4℃）、高温（40℃）、紫外线和盐胁迫时，ZmrbohB-α的转录本显著积累。此外，除伤口外，几种非生物刺激也影响ZmrbohB的可变剪接模式。这些结果为植物rboh基因表达调控的作用提供了新的见解，并表明ZmrbohB基因可能在响应环境胁迫中发挥作用。
