硝普钠（SNP）和茉莉酸甲酯（MeJA）诱导的白桦Ty1-copia类逆转座子的克隆及分析

摘要

We designed the primers of reverse transcriptase according to the conserved domains of the Ty1-copia retrotransposons reverse transcriptase.We obtained several fragments of reverse transcriptase from callus of birch by using improved RT-PCR.Eleven and nine fragments were amplified from callus of birch treated by sodium nitroprusside ( SNP) and methyl jasmonate (MeJA), respectively.The length of 21 reverse transcriptase sequences (named Bprt 1-21) is from 205 to 290 bp, with the consistency of 71.93%, the heterogeneity of from 1.1% to 50.9% and the heterogeneity of amino acid se-quences of from 0.0% to 57.1%.The sequences from birch treated by SNP or MeJA are clustered, respectively.The transcription of Ty1-copia-like retrotransposons can be activated by different signals.The analysis of the phylogenetic tree of reverse transcriptase of Ty1-coip a-like retrotransposons between birch and apple revealed each of the reverse transcripta-ses are clustered together, but the evolutional relationship between Bprt9, Bprt11 and DQ410750 are closer.Bprt15, Bprt19, DQ410751 and DQ410753 are clustered together.Therefore, the horizontal transmission can exist in retrotrans-posons.%利用 Tyl-copia类逆转座子逆转录酶（ RT）的保守区域设计引物，优化了扩增条件后利用RT-PCR从白桦愈伤组织中得到了1条逆转录酶序列。利用硝普钠（ SNP）和茉莉酸甲酯（ MeJA）诱导后分别扩增克隆了11条和9条逆转录酶序列。这21条逆转录酶序列（命名Bprt1-21）变化范围为205～290 bp，一致性为71．93％，异质性为11．％～50．9％，翻译成氨基酸的异质性为0～57．1％。经SNP和MeJA处理的样品中，获得的逆转录酶序列基本是分别聚类，初步证明不同的Ty1-copia类逆转座子能够分别响应不同的信号而被转录激活。分析所获得的21逆转录酶序列和苹果中19条逆转录转座子序列（ DQ410748～DQ410766）进化关系发现，逆转录酶基本各自聚类，但是Bprt9、Bprt11和DQ410750进化关系比较接近，Bprt15、Bprt19、DQ410751和DQ410753聚为一类，证明逆转座子存在水平传递。