香蕉中4条乙醇脱氢酶基因的克隆及表达分析

该研究采用RACE技术从香蕉中克隆了4条乙醇脱氢酶基因——MaADH1(GenBank No.KM253748)、MaADH2(GenBank No.KM253749)、MaADH3(GenBank No.KM253750)、MaADH4(GenBank No.KM253753)，且在核苷酸水平上4条基因与2A基因组中的乙醇脱氢酶同源性较高；遗传进化树分析显示，MaADH2、MaADH3和MaADH4属于乙醇脱氢酶第I类，而MaADH1不属于第I类，也不属于第Ⅲ类。半定量RT-PCR分析显示，4条基因在不同器官中的表达量不同；不同激素、不同非生物胁迫以及生物胁迫处理后4条基因的表达显示，MaADH2受ABA、乙烯、茉莉酸、水杨酸、干旱和涝害诱导表达，最大表达量分别为 19.14、 428.19、 68.21、 61.79、53.73和108.43；MaADH3受盐胁迫诱导表达，最大表达量为220.27；MaADH1和MaADH4在不同处理后的表达量变化不明显。研究表明，在香蕉中MaADH2可以作为ABA、乙烯、茉莉酸、水杨酸、干旱和涝害的标记基因，MaADH3可以作为盐害的标记基因。

Molecular Cloning and Expression of Four Alcohol Dehydrogenase (ADH) Genes from Banana

In this study,we report the molecular characteristics of four ADH genes MaADH1 (GenBank No.KM253748),MaADH2 (GenBank No.KM253749),MaADH3 (GenBank No.KM253750) and MaADH4 (GenBank No.KM253753) cloned from the banana plant (Musa acuminate L.AAA group,cv.Cavendish) using RACE based strategy.At the nucleotide acid level,these genes share a sequence high similarity with ADHs in the banana DH-Pahang (AA group) genome.Phylogenetic analysis showed that the deduced amino acid sequences of MaADH2,MaADH3 and MaADH4 belong to the first class,MaADH1 does not belong to the first and third classes.Expression analysis by semi-quantitative RT-PCR revealed that these genes were differentially expressed in various tissues.In addition,their expression was regulated by various stress conditions,including exposure to ABA,ethylene,JA,SA,cold,salinity,drought,flood and Fusarium oxysporum f. specialis(f.sp) cubense Tropical Race 4 (Foc TR4).The results showed that MaADH2 was strongly induced by ABA,ethylene,JA,SA,drought and flood,the maximum relative expression is 19.14,428.19,68.21,61.79,53.73 and 108.43 respectively.The MaADH3 was strongly induced by NaCl and its maximum relative is 220.27.MaADH1 and MaADH4 were induced by four hormones,abiotic stress and biotic stress,but the expression quantity change was little.This study demonstrated that the MaADH2 was found to be a potential marker gene of ABA,ethylene,JA,SA,flood and drought stress in the banana,the MaADH3 was found to be a potential marker gene of salt stress in the banana.