皖豫高效抗逆大豆根瘤菌Y2-4的选育

Screening of Highly Efficient and Stress-tolerant Soybean Rhizobium Y2-4 Used in Anhui and Henan Provinces

为筛选适合安徽、河南两地的大豆高效抗逆根瘤菌,从安徽和河南两地选取7个采样点采集大豆根瘤并分离根瘤菌,通过系统发育分子鉴定、回接大豆筛选、抗逆境胁迫能力测定筛选高效抗逆大豆根瘤菌,并通过初步田间接种试验对其促生效果进行了评估。结果显示:共分离得到621株大豆根瘤细菌,其中Sinorhizobium属菌株418株(67.3%),是该地区的优势大豆根瘤菌,Bradyrhizobium属菌株198株(31.9%),Rhizobium属菌株5株(0.8%,回接大豆不能结瘤)。筛选得到1株具有应用潜力的高效抗逆根瘤菌S.fredii Y2-4,与参比菌株CCBAU 45436相比,Y2-4菌株接种的大豆叶绿素含量、根瘤数、地上干重分别提高了1.8%、15.5%和9.8%,且在3%NaCl盐胁迫及38℃高温胁迫条件下仍具有生长能力。田间接种试验结果显示,在全氮(225 kg·hm^(-2)复合肥,氮磷钾比例15∶15∶15)、减氮26.6%(225 kg·hm^(-2)复合肥,氮磷钾比例11∶15∶15)、不施氮(225 kg·hm^(-2)复合肥,氮磷钾比例0∶15∶15)3种氮肥水平下接种Y2-4菌株均可以提高大豆产量,“减氮26.6%+接种Y2-4”处理较“全氮+不接种”处理条件下,大豆产量增加了25.5%。综上所述,Y2-4菌株可以作为皖豫两省部分地区的大豆高效抗逆根瘤菌接种菌株进行推广应用。

In order to screen highly stress-resistant rhizobia suitable for soybean in Anhui and Henan provinces,we selected seven sampling sites in Anhui and Henan provinces to isolate soybean rhizobia from soybean root nodules,and identified them by phylogenetic molecular characterization,inoculating back to soybean,determination of resistance to stress,and evaluation of its growth-promoting effect through preliminary field inoculation trials.The results were as follows:621 soybean rhizobia strains were isolated,including 418 strains of Sinorhizobium(67.3%),which is the dominant soybean rhizobial in the region,198 strains of Bradyrhizobium(31.9%),and 5 strains of Rhizobium(0.8%,which could not effectively nodulated soybean).Compared with the reference strain CCBAU 45436,the chlorophyll SPAD value,nodule number and shoot dry weight of soybean inoculated with strain Y2-4 increased by 1.8%,15.5%and 9.8%,respectively.Moreover,Y2-4 had the ability to grow under 3%NaCl salt stress and 38℃high temperature stress.The result of the initial field inoculation trials showed that inoculation of Y2-4 at three nitrogen fertilization levels,full nitrogen(225 kg·ha^(-1) of compound fertilizer,NPK ratio 15∶15∶15),reduced nitrogen 26.6%(225 kg·ha^(-1) of compound fertilizer,NPK ratio 11∶15∶15),and no nitrogen application(225 kg·ha^(-1) of compound fertilizer,NPK ratio 0∶15∶15),could improve soybean yield.The"26.6%N reduction+Y2-4 inoculation"treatment increased soybean yield by 25.5%compared with"full N+uninoculation"treatment.The above results indicate that the excellent Y2-4 strain can be promoted and applied as an efficient and resistant rhizobial inoculum strain for soybean in some areas of Anhui and Henan provinces.