巴西橡胶树死皮病相关基因Hb Myb1的结构分析及表达

Structural Analysis and Expression of HbMyb1 Gene Associated with Tapping Panel Dryness of Hevea brasiliensis

对与死皮病有密切关系的HbMyb1基因进行了克隆和结构分析。该基因含有一个 34 4bp的内含子和2个外显子。利用GenomeWalker的方法获得了 1.2kb的 5′前导序列核心启动子 ,分析表明该启动子可能是富含GC和依赖于起始子 (Inr)的非典型启动子。Southern杂交分析表明 ,HbMyb1在橡胶树基因组中为2个拷贝。HbMyb1在树皮中表达最强 ,在叶片中最弱。

Two primers were designed based on the sequence of HbMyb1 cDNA,which was found to be closely related with tapping panel dryness(TPD),a complex physiological syndrome widely found in Hevea brasiliensis plantations,in a previous study (Chen et al.2003), to amplify the corresponding DNA using PCR (Fig.1). The amplified product was 1 277 bp in length with a 344 bp intron and two exons (Fig.2). The results of protein domain prediction indicate that there may be a N-glycosylation site, three cAMP- and cGMP-dependent protein kinase phosphorylation sites, a protein kinase C phosphorylation site, nine casein kinase II phosphorylation sites, five N-myristoylation sites, an amidation site and an ATP/GTP-binding site. The 5′ leader sequence of HbMyb1 was obtained by using GenomeWalker (Figs.3, 4). The Promoter Prediction software analysis indicated that there are not typical promoter region and there are not intron in 5′ regulatory region.The promoter of HbMyb1 is not a typical promoter,it may be a housekeeping gene in low level expression.The results of Southern analysis indicated that HbMyb1 has two copies in the Hevea brasiliensis genome (Fig.5). Northern analysis showed that in healthy trees HbMyb1 was expressed highest in bark (near cambium) and lowest in leaf (Fig.6).