广西红菇子实体及分离株的rDNA ITS序列分析

为了研究广西食用红菇rDNA ITS片段遗传多样性，鉴别红菇组织分离株的真伪，用一对通用引物对采自广西浦北县、容县和上思县的18个红菇子实体样本及3个组织分离株的rDNA ITS片段进行PCR扩增，扩增产物纯化后测序，运用相关序列分析软件对ITS区全序列进行分析，并和GenBank／EMBL／DDBJ三大核酸序列数据库进行同源性检索。结果获得12个红菇子实体和3个分离株的ITS和5．8S rDNA区段的完整序列，3个分离株的ITs序列全长明显小于子实体样本的ITS序列全长；3个组织分离株与红菇属真菌的遗传距离大；除2个采自浦北龙门的子实体与其它子实体的同源性小于0．95外，来自不同区域的其余子实体样本间rDNA ITS序列同源性都达到0．98以上；12个子实体的ITS区段与GenBank中已知的红菇属真菌的相似率都不大于0．90。由此推断3个组织分离株均不是红菇的分离株而可能是子实体的寄生菌或污染菌；广西浦北县、容县和上思的食用红菇样本没有地理类群差异，但在浦北产区可能存在多种食用红菇共同生长。

Nucleotide Sequence Analysis on ITS rDNA of Fruitbodies and Isolates of Russula in Guangxi

To analyze the genetic diversity on ITS rDNA of edible Russula fungi in Guangxi,China and to authenticate isolates by means of sequence analysis,the rDNA ITS regions of fruitbodies and isolates were amplified using primer pair ITS-P1,ITS-P4,and then purified and sequenced.Total ITS sequence analysis were performed using software BioEdit v5.06 and Clustal X1.8,and BLAST matched with GenBank database on homology.The total ITS rDNA sequences of twelve fruitbodies and three isolates were obtained,and the sequence length of three isolates were less than fruitbodies.The difference in sequence alignment,homogenous analysis and BLAST match demonstrated that the genetic distance of isolates were far from Russula fungi evidently.The sequence similarities of all fruitbodies from three geographical situs were up to 0.98 except for two from Pubei county,and the sequence similarities between either bodies and species of Russula from GenBank database couldn't identify to species level.The result demonstrated that three isolates used in our study were not the right strains of Russula fungi but potential parasites of fruitbody or contamination,and there wasn't geobiological difference between edible Russula specimens obtained from Pubei county,Rongxian county and Shangsi county in Guangxi,but up to two species of edible Russula occured potentially in Pubei county.