基于高通量测序的银木内生细菌多样性分析

Diversity Analysis of Endophytes in Cinnamomum septentrionale Based on High-throughput Sequencing

近年来城市绿地盐碱化问题持续加重,南方常见绿化树种樟树多出现长势衰弱和叶片黄化现象。武汉市园林科学研究院通过长期研究发现,樟科植物银木(Cinnamomum septentrionale Hand. Mazz)相对于樟科其他植物具有长势良好、耐盐碱、树形挺拔等诸多优势,是优秀的园林行道绿化树种。为了进一步对这一优良绿化树种展开研究,探究其茎和叶片内生细菌的种类、功能以及群落结构,采用高通量测序技术,对栽种于武汉市园林科学研究院的1 a生盆栽银木进行了生物多样性分析以及微生物群落鉴定。结果表明:银木茎、叶片中内生菌有效序列分别为89 434和95 218条,有效序列平均长度均为406 bp,银木茎内生细菌的Chao1指数、Simpson指数和Shannon指数均高于叶片。银木茎和叶片内生菌在门水平上的优势菌群为厚壁菌门(Firmicutes)、变形菌门(Proteobacteria)、蓝藻门(Cyanobacteria)、拟杆菌门(Bacteroidetes)和放线菌门(Actinobacteria)。银木叶片与茎内生菌属水平群落结构差异不大。尽管不同植物内生菌菌落结构存在显著差异,但内生菌的功能基因数量存在一定程度的相似性。对银木内生菌功能基因的表达状况进行分析,发现银木茎与叶片内生菌在功能基因的表达上具有显著差异,猜测这与银木茎木质化程度较叶片高,内生细菌定植环境存在较大差异有关。

In recent years,the problem of salinization and alkalization of urban green spaces has continued to worsen,and camphor trees,the common green tree species in the south,have shown signs of weakened growth and yellowing of leaves.Wuhan Academy of Landscape Sciences has found that Cinnamomum septentrionale,a plant of the Lauraceae family,has many advantages over other plants of this family,such as good growth,salt alkali resistance,and upright tree shape.It is an excellent tree for landscaping and road greening.In order to further study this excellent green tree,explore the types,functions,and community structure of endophytes in its stems and leaves,high-throughput sequencing technology was used to analyze the biodiversity and microbial community identification of 1-year-old potted C.septentrionale planted in Wuhan Academy of Landscape Sciences.The results showed that there were 89434 and 95218 effective sequences of endophytic bacteria in the stem and leaves,respectively,with an average length of 406 bp.The Chao1 index,Simpson index,and Shannon index of endophytic bacteria in stems were higher than those in leaves.The dominant communities of endophytes in the stem and leaves are Firmicutes,Proteobacteria,Cyanobacteria,Bacteroidetes,and Actinobacteria.There was not much difference in the horizontal community structure of endophytes in the leaves and stem.Although there are significant differences in the colony structure of endophytes among different plants,there is a certain degree of similarity in the number of functional genes of endophytes.The expression of functional genes in endophytes of C.septentrionale was analyzed,revealing significant differences in the expression of functional genes between the stem and leaves.It is speculated that this is related to the higher degree of lignification in the stem compared to the leaves,and the significant differences in the colonization environment of endophytes.