抗根肿病大白菜材料SSR分子标记的初步筛选

为了明确抗根肿病大白菜材料CCR12049中的抗病基因，进一步开发分子标记。以高抗根肿病的高代自交系大白菜CCR12049、高感根肿病的高代自交系大白菜CM12081、CCR12049和CM12081杂交得到的F₁及F₁自交构建的F₂分离群体为试材，通过人工接种鉴定、聚丙烯酰胺凝胶电泳和序列比对。结果显示，该抗病材料中的根肿病抗性由显性单基因控制；36对引物在2个亲本和F₁中初步筛选出4对有多态性的引物，在F₂中进一步验证，发现只有1对(cr-26)在F₂中的扩增结果与表型鉴定一致；2个亲本及F₁的PCR产物测序比对发现，在95~111 bp这个位置，抗病亲本和F₁的序列完全相同，但是感病材料在这个位置出现了17个碱基(TCTCTATCTCTTACGCA)的缺失。可以推断抗病材料可能是由于这17个碱基的插入从而表现出抗病性，该标记可以将抗感材料区分开，该标记可以作为一个初步筛选白菜抗根肿病的SSR分子标记来利用。

Preliminary Screening of SSR Molecular Markers for Resistance to Clubroot in Brassica rapa L. ssp. pekinensis

In order to identify the clubroot resistance gene in Chinese cabbage cultivar CCR12049 and develop molecular markers, the following materials were employed: CCR12049, a high-generation inbred line with high resistance to clubroot disease, CM12081, a high-generation inbred line with high susceptibility to clubroot disease, F₁ generation resulting from the cross between CCR12049 and CM12081, and the F₂ generation segregating populations created through selfing of the F₁ generation. Through artificial inoculation identification, polyacrylamide gel electrophoresis, and sequence alignment, it was demonstrated that the disease resistance in tested materials was governed by a dominant single gene. 36 primer pairs were initially tested on both the parental lines and F₁ generation, 4 primer pairs exhibiting polymorphism were identified. Subsequent validation in the F₂ generation revealed that only one pair (cr-26) yielded amplification results consistent with the observed phenotype in the F₂ generation. Through sequencing comparison of the PCR products obtained from the two parental lines and F₁, it was observed that the sequences of the resistant parents and F₁ were identical within the range of 95 bp to 111 bp. Conversely, in the susceptible materials, a deletion of 17 bases (TCTCTATCTCTTACGCA) was identified. These findings suggest that the resistance observed in the impermeable materials may be attributed to the insertion of these 17 bases. This marker has the capability to distinguish the resistant materials and can serve as an SSR marker for the initial screening of clubroot resistance in Chinese cabbage.