3个水稻WAX2同源基因表达的组织特异性及逆境响应特征

利用拟南芥的WAX2基因序列BLAST检索出3个水稻同源基因,命名为OsWAX2-1、OsWAX2-2和OsWAX2-3,与拟南芥WAX2基因的同源性分别为56.0%、55.2%和52.0%;其预测的编码蛋白与WAX2蛋白的同源性分别为61.5%、60.5%和64.7%。这3个蛋白都分别存在4个跨膜结构区和1个甾醇去饱和酶的保守区,说明它们都属于跨膜蛋白并可能与角质层的蜡质合成有关。采用半定量RT-PCR方法检测3个OsWAX2基因在水稻不同部位的表达情况,及高温、低温、NaCl、PEG和ABA5种处理对3个OsWAX2基因在转录水平表达的影响。结果表明,3个OsWAX2基因在水稻中的表达存在时空差异,3个基因在水稻萌动的胚中表达量都很高,OsWAX2-3基因在叶中的表达量最高;3个OsWAX2基因对高温、低温、盐、干旱及ABA胁迫响应也存在差别,OsWAX2-1只在ABA处理时增强表达;OsWAX2-2受高温、低温、盐、干旱胁迫及ABA诱导并且响应迅速。这一结果为进一步研究OsWAX2基因在水稻生长发育过程及逆境胁迫下的功能与作用机制提供了参考。

Tissue Speciality and Stress Responses in Expression of Three WAX2 Homologous Genes in Rice

Plant surface is covered by epidermis with a layer of wax. It can regulate non-stomatal water loss, protect against ultraviolet radiation damage and germ invasion. WAX2 gene in Arabidopsis is involved in cuticular wax production and significantly affects leaf water evaporation. Three WAX2 homologous genes in rice, named OsWAX2-1, OsWAX2-2, OsWAX2-3 were found by BLAST search in the NCBI database, with the homology of 56.0%, 55.2%, and 52.0% to Arabidopsis WAX2 gene respectively. Homology of their predicted proteins to Arabidopsis WAX2 protein was 61.5%, 60.5%, and 64.7%, respectively. All of the three proteins had four transmembrane domains and a conserved sterol desaturase domain, suggesting that OsWAX2 proteins are transmembrane proteins and may be related to plant cuticular wax biosynthesis. Expression patterns of the three rice WAX2 homologs were analyzed using semi-quantitative RT-PCR. The results showed that the three OsWAX2 genes had tissue speciality in expression. They also exhibited different expression patterns under high-temperature, low temperature, NaCl, PEG and ABA treatments. These results could be useful for further functional characterization of the three OsWAX2 genes.