摘要
以5个已知S基因型的中国白梨品种为试材,设计分别对应于梨SFBB-alpha,SFBB-beta和SFBB-gamma基因的3对引物对这5个品种进行基因组PCR扩增。结果仅引物组合PSFBG-F/PSFBG-R从‘金花’（S13S18）,‘金花四号’（S13S18）和‘鹅梨’（S13S34）中扩增出一约1300bp的条带,经回收、克隆、测序后,鉴定其为SFBB-gamma基因,命名为PbSFBB13-gamma（Pyrus bretschneideri SFBB13-gamma）,GenBank登录号为EU081892。逆转录PCR结果表明PbSFBB13-gamma仅在花粉中特异表达;序列分析表明该基因不含内含子,编码区含1191个核苷酸,编码396个氨基酸,预测分子质量与等电点分别为45.4ku、4.63。PbSFBB13-gamma表现出典型的花粉SFB/SLF基因的基本结构特征,即1个F-box结构域及4个可变区;在推导氨基酸水平上,其与蔷薇科SFB/SLF基因的相似性为17.8%-97.7%。试验结果充分表明PbSFBB13-gamma应为花粉S基因的候选基因。选取蔷薇科34个SFB/SLF基因的全长氨基酸序列,构建进化树研究基因间的进化关系。结果表明,34个SFB/SLF基因形成2个亚科特异的类群,但不形成种特异的类群,其进化规律与蔷薇科S-RNase基因一致,即花粉SFB/SLF基因的形成也是在亚科形成之后、种形成之前。研究结果有助于从分子水平上揭示中国白梨的自交不亲和性机制。
Five Chinese White Pear（Pyrus bretschneideri）cultivars,with known S-genotypes,were used in this study.The genomic DNAs were extracted and amplified by PCR with three pairs of primers corresponding to pear SFBB-alpha,SFBB-beta and SFBB-gamma genes,respectively.Results showed that only one primer pair PSFBG-F/PSFBG-R successfully amplified a fragment of approximately 1 300 bp from ＇Jinhua＇（S_ 13S_ 18）,＇Jinhuasihao＇（S_ 13S_ 18）and ＇Eli＇（S_ 13S_ 34）corresponding to pear SFBB-gamma gene.This gene was named PbSFBB13-gamma（Pyrus bretschneideri SFBB13-gamma）and deposited under GenBank accession No.EU081892.RT-PCR revealed that the PbSFBB13-gamma was expressed specifically in the pollen grains.The coding region of the PbSFBB13-gamma was 1 191 bp in length encoding 396 amino acids with a predicted molecular weight of 45.4 ku and isoeletric point of 4.63.The SFBB13-gamma displayed the typical structural characterization of SFB/SLF genes,i.e.an F-box motif and four variable regions.At the deduced amino acid level,it shared 17.8% to 97.7% similarities with other SFB/SLFs of rosaceous plants.These characteristics of PbSFBB13-gamma fully demonstrate that it is a candidate of pollen S-gene although its function in gametophytic self-incompatibility（GSI）response is not confirmed yet.Phylogenetic analysis revealed that 34 rosaceous SFB/SLFs were dived into two subfamily-specific groups,but did not further form species-specific subgroup.The evolutionary pattern of SFB/SLFs concurs with that of rosaceous S-RNases,suggesting that SFB/SLFs occur after divergence of subfamily but before the divergence of species as S-RNases do in Rosaceae.The present study could provide a scientific base for fully clarifying the mechanism of pear GSI at the molecular level.
出处
《林业科学》
EI
CAS
CSCD
北大核心
2009年第11期36-43,共8页
Scientia Silvae Sinicae
基金
Supported by the Youth Foundation of Education Bureau of Hunan Province(1014586)
the Key Project of State Forestry Administration(2006-12)
the Important Project of Ministry of Education
关键词
白梨
配子体自交不亲和性
花粉S基因
S位点F-box基因
进化树
Chinese White Pear（Pyrus bretschneideri）
gametophytic self-incompatibility
pollen S-gene
S-locus-linked F-box gene
phylogenetic tree
作者简介
Author for correspondence： Tan Xiaofeng.
