台风经常造成我国香蕉大面积减产甚至绝收。植物对倒伏的抗性主要取决于茎秆中木质素的含量。4-香豆酸:CoA连接酶(4CL)是植物木质素合成途径中的一个关键酶。我们前期将杨树木质部特异表达启动子proPtCOMT和Mu4CL3转化进拟南芥，转基因植株的木质素含量和倒伏抗性显著高于野生型。本研究计划在这些结果的基础上，将Mu4CL3转化进我国香蕉主栽品种巴西蕉和威廉斯，使其在香蕉植株的假茎中过量表达，同时运用RNAi使Mu4CL3在香蕉植株假茎中减量表达；通过GC-MS、核磁共振NMR分析转基因植株木质素结构的变化；观察香蕉植株假茎、根以及管胞的细胞壁结构的变化；监测proPtCOMT驱动下Mu4CL3在香蕉植株中的组织特异性表达；研究两种不同的RNAi载体构建方式对基因沉默效率的影响；分析转基因植株4CL酶活、木质素含量和倒伏抗性之间的关系；获得香蕉抗倒伏种质，为培育香蕉抗风新品系奠定基础。

The production of banana in China is always affected heavily by typhoon. Plant's lodging resistance is mainly determined by lignin content in stem. 4-coumarate:CoA ligase is a key enzyme in lignin synthesis pathway in plants. We had transformed an xylem-specially expressing promoter, proPtCOMT and Mu4CL3, a 4-coumarate:CoA ligase (4CL) gene isolated from banana, into Arabidopsis. Both lignin content and lodging resistance of transgenic plants were higher than those of wild type. In this item, we are going to transform Mu4CL3 into Brazillian and Williams, two banana varieties that were large-scale planted in China. Mu4CL3 will be over-expressed in banana. At the same time, Mu4CL3's expression will be repressed using RNAi technique. Lignin composition in transgenic plants will be analyzed through GC-MS and NMR. Pseudostem, root and the composition of tracheid's cell wall will also be studied. The tissue-specific expression of Mu4CL3 will be monitored. We are also going to study the gene silencing efficiency caused by different RNAi vector-constructing method. The relationship among 4CL enzyme activity, lignin content and lodging resistance will be analyzed. We are also going to get new banana typhoon-resistant germplasms. Breeding new banana typhoon-resistant varieties will be prepared through this item.