十字花科黑腐病菌中一个与黄色素合成相关基因的鉴定  

Identification of a Gene Involved in Pigment Synthesis in Xanthomonas campestris pv. campestris

作　　者：杨国奎[1] 祁艳华[1] 朱艳宁[1] 冷明[1] 叶玉云[1] 苏辉昭[1] 陆光涛[1,2] 

机构地区：[1]广西大学生命科学与技术学院,南宁530005 [2]亚热带农业资源保护与利用国家重点实验室,南宁530005

出　　处：《基因组学与应用生物学》2014年第4期802-807,共6页Genomics and Applied Biology

基　　金：国家自然科学基金(31171206)项目资助

摘　　要：十字花科黑腐病菌(Xanthomonas campestris pv.campestris,简称Xcc)能够产生大量的胞外多糖。胞外多糖商品名又称为黄原胶,具有广泛用途,在食品生产中可作为添加剂使用。为了得到不含黄色素的黄原胶,我们采用转座子EZ-Tn5随机插入诱变的方法对8004菌株进行突变,获得了一株不产黄色素的突变体。通过对突变体的转座子EZ-Tn5插入位点进行分析,发现该突变体是由于编号为XC_4097的基因被插入突变后衍生而来。同源性分析表明XC_4097编码一种脂质酰基转移酶,它与脂质的合成有关。采用同源双交换方法构建XC_4097基因的缺失突变体。通过对野生菌、突变体以及功能回补体的表型分析进一步证实了XC_4097基因功能的丧失只影响黑腐病菌黄色素的合成,而不影响细菌生长以及胞外多糖的合成。这为工业上生产无黄色素的黄原胶提供了应用基础。Xanthomonas campestris pv. campestris（Xcc） produces a mass of exopolysaccharides, which are also called xanthan gum. Xanthan gum could be used in a variety of products, including used as additive agents in food production. In order to attain the non-pigment xanthan gum, Xcc8004 strain was mutanted by using transposon EZ-Tn5 and a mutant strain producing no pigment was isolated. Further analysis revealed that the mutant is derived from the insertion of EZ-Tn5 in XC_4097 in the genome of 8004 strain. Sequence analysis showed that this gene is predicted to encode a lipid acyl transferase, which is involved in lipid synthesis. The XC_4097 deletion mutant was constructed by the method of homologous double-crossover. Through analyzing phenotype of wild type, mutant and complementary strains demonstrate that the XC_4097 involved in pigment synthesis but not exopolysaccharides（EPS） yield and growth in Xcc. This work provides foundation for producing xanthan gum without pigment.

关 键 词：十字花科黑腐病菌 胞外多糖 黄色素 XC_4097 

分 类 号：S436.3[农业科学—农业昆虫与害虫防治]