Heterologous expression of two Medicago truncatula putative ERF transcription factor genes, WXP1 and WXP2, in Arabidopsis led to increased leaf wax accumulation and improved drought tolerance, but differential response in freezing tolerance
Heterologous expression of two Medicago truncatula putative ERF transcription factor genes, WXP1 and WXP2, in Arabidopsis led to increased leaf wax accumulation and improved drought tolerance, but differential response in freezing tolerance
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DOI：
10.1007/s11103-007-9150-2
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发表时间：
2007-03
影响因子：
5.1
通讯作者：
Jiyi Zhang;C. Broeckling;L. Sumner;Zeng‐Yu Wang
中科院分区：
文献类型：
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作者：
Jiyi Zhang;C. Broeckling;L. Sumner;Zeng‐Yu Wang
角质层蜡质是植物角质层的主要组成部分，在保护地上器官免受生物和非生物胁迫的伤害方面起着重要作用。本文报道了蒺藜苜蓿ERF转录因子基因WXP 1及其同源基因WXP 2的功能研究。根据鲜重或表面积评估，WXP 1和WXP 2在拟南芥（生态型哥伦比亚）中的转基因表达导致4周龄和6周龄转基因植物叶片表皮蜡沉积显着增加。WXP 1和WXP 2植株蜡质组分的积累量和链长分布存在差异。WXP 1和WXP 2转基因植株的主要蜡质成分正构烷烃含量显著增加，而WXP 1转基因植株的另一种蜡质成分伯醇含量增加，而WXP 2转基因植株的正构烷烃含量减少。通过叶绿素淋失试验分析了转基因植株叶片的角质层特性，WXP 1植株没有发生变化，而WXP 2植株表现出更多的叶绿素淋失。对离体叶片鲜重损失的分析表明，转基因叶片往往比对照保留更多的水分。WXP 1和WXP 2转基因植株的耐旱性均显著增强。通过对全株耐冻性的分析和离体叶片电解质渗漏量的测定，发现WXP 1植株的耐冻性比对照提高，而WXP 2植株对低温的敏感性比对照提高。WXP 1的转基因表达对植株的生长发育没有明显的影响，而WXP 2的转基因表达导致植株生长缓慢。这些结果表明，WXP 1是一个通过遗传转化提高植物耐旱性和抗冻性的有用候选基因。
Cuticular waxes are the major components of plant cuticle and play an important role in protecting aerial organs from damage caused by biotic and abiotic stresses. Here we report the functional characterization of two putative ERF transcription factor genesWXP1and its paralogWXP2fromMedicago truncatula. Transgenic expression ofWXP1andWXP2inArabidopsis(ecotype Columbia) led to significantly increased cuticular wax deposition on leaves of 4-week-old and 6-week-old transgenic plants, assessed based on fresh weight or based on surface area. Differences in the accumulation of various wax components as well as their chain length distributions were found in theWXP1andWXP2plants. The major wax component inArabidopsis,n-alkanes, increased substantially in bothWXP1andWXP2transgenics, however, another wax component, primary alcohols, increased inWXP1plants but decreased inWXP2plants. Cuticle properties of the transgenic leaves were analyzed by chlorophyll leaching assay; while theWXP1plants had no change, theWXP2plants showed more chlorophyll leaching. Analysis of fresh weight loss from detached leaves revealed that the transgenic leaves tend to retain more water than the control. BothWXP1andWXP2transgenic plants showed significantly enhanced whole plant drought tolerance. Analysis of freezing tolerance at the whole plant level and measurement of electrolyte leakage from detached leaves revealed that theWXP1plants had increased freezing tolerance while theWXP2plants were more sensitive to low temperature when compared to the control. Transgenic expression ofWXP1had no obvious effects on plant growth and development, however, the expression ofWXP2led to slower plant growth. These results indicate thatWXP1is a useful candidate gene for improving plant drought and freezing tolerance by genetic transformation.