巴西橡胶树HbMKK4基因的克隆及表达分析

Molecular Cloning and Expression of HbMKK4 from Hevea brasiliensis(Para Rubber Tree)

采用RACE技术,从橡胶树‘热研7-33-97’中克隆了1个促分裂原活化蛋白激酶的激酶(MKK)基因HbMKK4。该基因全长cDNA序列1 580bp,编码框1 059bp,编码352个氨基酸,含有S_TKc结构域,其编码蛋白的分子量为38.83kD,理论等电点为9.36。实时荧光定量PCR结果显示,HbMKK4在橡胶树的根、树皮、胶乳及叶片中均有表达。割胶、茉莉酸甲酯和乙烯利均能上调胶乳中HbMKK4基因的表达,基因相对表达量分别在割胶后2h、茉莉酸甲酯处理8h和乙烯利处理4h后达到最高。研究结果推测HbMKK4可能通过MAPK信号途径参与茉莉酸信号途径的响应,可能在天然橡胶生物合成调控中起关键作用。

In this work,the full length cDNA of HbMKK4 was obtained from cDNA library in latex of rubber tree clone‘CATAS 7-33-97＇by RACE.It was 1 580 base pair（bp）in length,containing a 1 059 bp open reading frame（ORF）which encodes 352 amino acid with a predicted molecular mass of 38.83 kD and pI 9.36.The deduced amino acid sequence contain S_TKc domain.Comparing expression among different tissues showed that HbMKK4 was expressed in root,bark,latex and leaves.HbMKK4 transcript levels were significantly upregulated in latex by tapping,methyl jasmonate and ethephon treatment for rubber tree.The transcript levels peaked in 2hours by tapping,8hours by methyl jasmonate and 4hours by ethephon treatment,respectively.These results suggested that HbMKK4,a member of MAPK cascade,might plays a role in rubber biosynthesis via JA pathway in rubber tree.