利用SSR分子标记技术对5个贵州柑橘地方品种的遗传背景进行分析．结果表明，24对SSR引物在5个地方品种和参与D N A指纹比对的14个栽培品种中共检测到92个等位基因，每个位点的等位基因数变幅为2～7个，平均为3.8个；多态性信息含量（PIC）变化范围在0.36～0.78之间，平均为0.49．经过DNA指纹比对，发现其中5对引物扩增的8条特征谱带可作为地方品种鉴别的参考性标记．利用NTSYS软件进行相似性系数计算，采用 UP‐GM A法聚类，结果显示，相似性系数为0.80，可将5个地方品种划分在不同的亚组中；地方品种米柑和牛肉红金橘均单独成组，其遗传背景独特；土柑与皱皮柑的亲缘关系较近；大果型冰糖橙与冰糖橙的遗传背景相同；红香柚与强德勒柚的遗传背景基本一致．
To study the functions of the early auxin-responsive genes Cs GH3.1 and Cs GH3.6 in citrus resistance against canker disease, we cloned Cs GH3.1and Cs GH3.6 in ‘Newhall' Navel Orange(Citrus sinensis Osbeck). They are 1 797 bp and 1 887 bp and encode 598 and 629 amino acids, respectively. In vitro mature leaves from susceptible ‘Newhall' and resistant Calamondin(C. madurensis) were inoculated by a Xanthomonas axonopodis pv. citri(Xac) bacterial suspension, and expression of Cs GH3.1 and Cs GH3.6 in the two varieties were analyzed using quantitative real-time PCR(q RT-PCR). ‘Newhall' leaves were treated with different hormones for 3 days, inoculated by Xac bacterial suspension, and then the symptoms in these leaves were investigated. We used q RT-PCR to analyze the effect of different hormones on Cs GH3.1 and Cs GH3.6 expression in ‘Newhall'leaves. The expression levels of both Cs GH3.1 and Cs GH3.6 were significantly induced by Xac in ‘Newhall' leaves, compared with levels in Calamondin leaves. 1-naphthy acetic acid(NAA) increased the hypertrophy of infection sites in ‘Newhall' leaves, while naphthyl-phthalamic acid(NPA)had no visible effect on lesion development. NAA hormone greatly improved expression of Cs GH3.1 in ‘Newhall', but not Cs GH3.6. These results indicate that the auxin primary-response gene Cs GH3.1 plays an important role in citrus susceptibility to Xac.
