为了研究巴西橡胶树中植物特有NAC转录因子的功能,笔者通过RT-PCR和实时荧光定量PCR技术对HbNAM的开放阅读框(ORF)进行了克隆和表达分析,并通过酵母转化实验进行转录激活活性分析。结果显示,HbNAM基因ORF为1 077 bp,编码358个氨基酸,在第12—167位氨基酸之间含有一个典型的NAC结构域,属于NAC转录因子家族中的NAM亚族。酵母试验表明,HbNAM在高度变异C端具有转录激活活性,具备转录因子的基本特征。实时荧光定量PCR分析发现,HbNAM在叶片、雄花、雌花、胶乳和树皮中均表达,其中以光合组织叶片和生殖组织雄花中的表达量最高,并且胶乳中该基因的表达受割胶、植物激素或植物生长调节剂茉莉酸(JA)和乙烯利(ET)以及低温胁迫影响,推测HbNAM可能与植物的生长发育和胁迫应答过程有关。
In order to identify the function of plant-specific NAC transcription factors inHevea brasiliensis, the wholeopen reading frame(ORF) sequence ofHbNAMwas cloned and analysed by using reverse transcription polymerase chainreaction(RT-PCR) as well as real-time PCR, and the transactivation activity analysis was carried out in yeast cells. Theresults indicated thatHbNAMoccupied an ORF of 1 077 bp, encoding a protein of 358 amino acids belonging to NAMsubgroup with a conserved NAC with domain from amino acid 12 to 167. Transactivation assay in yeast cells showed thatHbNAM protein possessed transcriptional activation activity in the highly divergent C terminal region. The realtime PCRindicated thatHbNAMcould express in leaves, male flowers,female flowers, latex as well as bark,and the hightest ex-pression of levels ofHbNAMwas in leaves and male flowers among these detected tissues. The expression ofHbNAMinlatex was affected by tapping,plant hormone jasmonate(JA), ethylene(ET) and cold stress treatment,which suggestedthatHbNAMmay have relationship with plant growth, development and stress responses in rubber tree.