酸性土壤中大豆优势根瘤菌的分离、鉴定及其生物学特性

从两个酸性土壤生态实验点（江西鹰潭、浙江金华）种植的不同大豆品种根瘤中,分离纯化出29个分离物,并对其进行了分子鉴定和生物学特性分析。从其中16个分离物中扩增出nifH基因,测序结果表明,分离纯化出的菌株主要为慢生根瘤属（Bradyrhizobium）菌株。10个分离自浙江金华的菌株,在大豆品种之间的种属差异不大。在6个分离自江西鹰潭的菌株中,耐铝和敏感的大豆品种根瘤菌株存在明显的基因型差异。通过基于nifH基因的系统发育分析选取代表性菌株,进行16S rDNA序列测定和菌株回接结瘤实验,进一步明确和验证了其种属特性。同时,对经过初筛能结瘤的4株根瘤菌进行了生长曲线和生理生化特性的测定。本文结果表明在酸性土壤中,优势根瘤菌存在地域差异性。

Isolation,identification and biological characteristics of Predominant rhizobia associated with soybean in acidic soil

This paper studied molecular identification and biological characteristics of 29 stains rhizobia isolated and purified from soybean nodules grown on different acidic soils with different soybean cultivation histories at Yingtan,Jiangxi province and Jinhua,Zhejiang province.The nifH gene fragment were amplified from 16 strains of 29 isolates.Sequence analysis of nifH showed that these strains belonged to the genus of Bradyrhizobium.Ten rhizobial strains were from Jinhua and showed no obviously difference among soybean cultivars.Six rhizobial strains were from the nodules of BX10（Al-tolerant） and BD2（Al-sensitive） at Yingtan and showed differences between these two soybean genotypes.Based on the phylogenetic analysis of nifH sequence,the species of selected soybean rhizobia were confirmed by 16S rDNA sequence analysis and rhizobial inoculants.Four rhizobial strains showed nodules in the roots of BX10 and BD2,and the growth curve and physiological and biochemical characteristics of them were further identified.Results suggested that dominant rhizobia in acidic soils showed regional differences.