Molecular genetical analysis of the two locus self incompatibility in the grasses (Poaceae)

禾本科植物的自交不亲和（SI）是由两个不连锁的基因座Sand Z在配子体上控制的，本项目旨在建立野生大麦Hordeum bulbosum （2x）自交不亲和的遗传基础，并克隆自交不亲和基因(s)。基本的遗传分析包括植物系杂交实验、SI基因型的确定、大作图群体的产生、与SI位点密切相关的DNA标记的鉴定等。为了克隆S基因，采用基于aflp的mRNA指纹图谱（AMF）方法，从花期雌蕊和花药中寻找S基因型特异性转录本。通过AMF分析，从雌蕊和花药转录本中检测到数十个S特异性片段。克隆这些片段并进行RFLP分析以检测与S位点的连锁关系。到目前为止，已有几个克隆被证实与S位点有密切的联系。利用S连锁克隆构建了S位点周围的详细遗传图谱。部分克隆与S位点之间未发现重组，表明这些克隆是S基因的候选克隆。应详细分析候选克隆的表达模式和序列多态性，以确定是否为S基因。为了证明候选基因是S特异性的决定因素，还需要开发球茎H的转化系统

The self-incompatibility (SI) in the grasses (Poaceae) is gametophytically controlled by two unlinked loci, Sand Z, The aim of this project is to establish the genetic basis of the SI in wild barley, Hordeum bulbosum (2x) and to clone the SI gene(s). The basic genetical analysis involves crossing experiments of plant lines, determination of SI genotypes, production of large mapping populations, identification of DNA markers closely linked to the SI loci, etc. Toward the,, cloning of the S gene, the AFLP-based mRNA fingerprinting (AMF) method was employed to search S genotype-specific transcripts from pistils and anthers at anthesis. By the AMF analysis, dozens of S specific fragments were detected from both the pistil and anther transcripts. The fragments were cloned and subjected to the RFLP analysis to examine linkage to the S locus. Several clones have so far been confirmed for the close linkage to the S locus. The S-linked clones were used to construct a detailed genetic map around the S locus. No recombination was found between the S locus and some of the clones, indicating that those clones are candidates of the S gene. The expression pattern and sequence polymorphism of the candidate clones should be analyzed in detail to examine whether they are the S gene or not. It is also necessary to develop the transformation system for H bulbosum to demonstrate that the candidate gene is the determinant of S specificity