Lee Saet Buyl, Kim Hyojin, Kim Ryeo Jin, Suh Mi Chung
Department of Bioenergy Science and Technology, College of Agriculture and Life Sciences, Chonnam National University, Gwangju, 500-757, Korea.
Plant Cell Rep. 2014 Sep;33(9):1535-46. doi: 10.1007/s00299-014-1636-1. Epub 2014 Jun 1.
Camelina has been highlighted as an emerging oilseed crop. Transgenic Camelina plants overexpressing Arabidopsis MYB96 exhibited drought resistance by activating expression of Camelina wax biosynthetic genes and accumulating wax load. Camelina (Camelina sativa L.) is an oilseed crop in the Brassicaeae family with potential to expand biofuel production to marginal land. The aerial portion of all land plants is covered with cuticular wax to protect them from desiccation. In this study, the Arabidopsis MYB96 gene was overexpressed in Camelina under the control of the CaMV35S promoter. Transgenic Camelina plants overexpressing Arabidopsis MYB96 exhibited normal growth and development and enhanced tolerance to drought. Deposition of epicuticular wax crystals and total wax loads increased significantly on the surfaces of transgenic leaves compared with that of non-transgenic plants. The levels of alkanes and primary alcohols prominently increased in transgenic Camelina plants relative to non-transgenic plants. Cuticular transpiration occurred more slowly in transgenic leaves than that in non-transgenic plants. Genome-wide identification of Camelina wax biosynthetic genes enabled us to determine that the expression levels of CsKCS2, CsKCS6, CsKCR1-1, CsKCR1-2, CsECR, and CsMAH1 were approximately two to sevenfold higher in transgenic Camelina leaves than those in non-transgenic leaves. These results indicate that MYB96-mediated transcriptional regulation of wax biosynthetic genes is an approach applicable to generating drought-resistant transgenic crops. Transgenic Camelina plants with enhanced drought tolerance could be cultivated on marginal land to produce renewable biofuels and biomaterials.
荠蓝已成为一种新兴的油料作物。过表达拟南芥MYB96的转基因荠蓝植株通过激活荠蓝蜡质生物合成基因的表达并积累蜡质负荷表现出抗旱性。荠蓝（Camelina sativa L.）是十字花科的一种油料作物，有潜力将生物燃料生产扩展到边际土地。所有陆地植物的地上部分都覆盖有角质蜡，以保护它们免受干燥影响。在本研究中，拟南芥MYB96基因在CaMV35S启动子的控制下在荠蓝中过表达。过表达拟南芥MYB96的转基因荠蓝植株生长发育正常，且对干旱的耐受性增强。与非转基因植物相比，转基因叶片表面的表皮蜡质晶体沉积和总蜡质负荷显著增加。转基因荠蓝植株中烷烃和伯醇的含量相对于非转基因植株显著增加。转基因叶片的角质蒸腾比非转基因叶片慢。对荠蓝蜡质生物合成基因进行全基因组鉴定使我们能够确定，转基因荠蓝叶片中CsKCS2、CsKCS6、CsKCR1-1、CsKCR1-2、CsECR和CsMAH1的表达水平比非转基因叶片高约2至7倍。这些结果表明，MYB96介导的蜡质生物合成基因的转录调控是一种适用于培育抗旱转基因作物的方法。具有增强耐旱性的转基因荠蓝植株可以种植在边际土地上，以生产可再生生物燃料和生物材料。
