早竹TB1同源基因的克隆和表达分析

竹笋的形成和生长发育过程涉及侧枝形态发生,探讨侧枝发育有关基因在竹笋发育过程中的作用,对于阐明竹笋发育基因调控机制有重要意义.利用禾本科TB1同源基因在序列上的保守性,在基因上游的非编码区设计简并引物,通过RT-PCR技术, 从早竹笋中克隆到一个1 296 bp的cDNA序列,该序列包含1个编码349个氨基酸的阅读框,在氨基酸水平上与玉米TB1相似性达64.7%,定名为PpTB1.序列分析比对表明,PpTB1基因的编码产物含有保守的SP区、TCP区和R区,属于基因家族的1个成员.进化分析进一步表明,竹子TB1相似基因是玉米TB1基因的同源基因,且竹子TB1同源基因的分歧时间介于水稻和现有其他TB1同源基因之间.RT-PCR分析表明,该基因在笋、叶片和花中均有表达.原位杂交分析表明,PpTB1在笋的侧芽中表达较多.研究表明,PpTB1很可能与禾本科其他植物的TB1同源基因相似,在竹笋发育过程中,参与侧枝的形成.另外,TB1同源基因也可能在竹子分类和进化研究上有重要价值.

Cloning and Expression Analyzing of TB1 Homologous Gene in Phyllostachys violascens

Previous studies revealed some anatomic and physiological mechanism about bamboo shoot development.But little is known about the molecular mechanism of shoot branching during bamboo shoot development.The studies on shoot branching related genes would therefore be helpful to elucidate the molecular mechanism.In this paper a 1 296 bp cDNA sequence was cloned from bamboo shoot of Phyllostachys violascens by RT-PCR method with degenerated primers based on the sequence conservation of Poaceae TB1 homologous genes.It has an open reading frame encoding 349 amino acids which has 64.7% identity with maize TB1 and thus is named PpTB1.Sequence alignment indicates that PpTB1 contains SP,TCP and R domain which are main characteristics of TB1 homologs in TCP protein family.Phylogeny analysis indicates that the divergence time of bamboo TB1 homologs are later than rice OsTB1 but earlier than other Poaceae TB1 homologs.Taken together,these TB1-like sequences are probably the TB1 homologous genes in bamboo.Although RT-PCR indicates that PpTB1 expression can be detected in leaf,bamboo shoot and young floret,the in situ hybridization reveals that the gene is highly expressed in axillary bud of bamboo shoot.Thus,PpTB1 may have similar function with its counterpart in grass and has the potential to regulate the production of bamboo shoot.In addition,TB1 homologous genes may also be valuable on the studies of bamboo taxonomy and evolution.