黄河三角洲田菁根瘤菌遗传多样性、高效菌株筛选及应用

	黄河三角洲田菁根瘤菌遗传多样性、高效菌株筛选及应用
	李项岳 1,2
学位类型	硕士
导师	解志红 ; 王其选
	2015-05-25
学位授予单位	中国科学院研究生院
学位授予地点	北京
关键词	黄河三角洲田菁根瘤菌遗传多样性高效菌株盐碱地改良
摘要	田菁（Sesbania cannabina）是盐碱地改良的优良豆科植物，接种匹配的高效根瘤菌能够促进田菁生长，并有望提高改良效果。本文从黄河三角洲的5个采样点及当地田菁的引种地之一的江苏如东的2个采样点采集田菁根瘤，分离、纯化、保藏根瘤菌198株，对比分析了两地田菁根瘤菌遗传多样性、种群结构及与土壤环境因子的关系，并进行了高效菌株筛选和田菁-根瘤菌互作改良黄河三角洲盐碱土地的应用试验。根据recA基因型选出18株代表菌株。代表菌株的16S rRNA 基因、持家基因（recA, atpD, glnII）进行遗传多样性和系统发育分析表明，黄河三角洲田菁根瘤菌分布于Ensifer、Neorhizobium、Rhizobium属：E. meliloti、N. huautlense、R. pusense及未定种Ensifer sp. I、Ensifer sp. II、Ensifer sp. III、Rhizobium sp. I、Rhizobium sp. II，及“Sesbanrhizobium”sp.。其中Ensifer sp. I为最大的类群，占黄河三角洲田菁根瘤菌总数的71%。江苏如东田菁根瘤菌包括E. meliloti、E. sesbania、N. huautlense及未定种Ensifer sp. I、Rhizobium sp. I。其中优势种为E. meliloti和N. huautlense，分别占45%、42%。田菁引入黄河三角洲后与其共生的根瘤菌种群结构发生了较大的变化。在一定范围内，pH对田菁根瘤菌的遗传多样性有着显著正相关影响，土壤盐分和速效磷含量对田菁根瘤菌的种群结构存在显著影响。共生基因nodA、nifH的系统发育分析表明，田菁根瘤菌不同种群间可能存在共生基因横向转移，使原来不与田菁结瘤的根瘤菌获得了与田菁共生的能力。温室盆栽实验中，所有的代表菌株都能跟田菁有效结瘤。筛选的高效菌株Ensifer sp. I YIC4027在蛭石培养条件下，表现出最好的促生效果、较高的固氮结瘤及耐盐碱能力。在小区试验中接种高效菌株的田菁比不接高效菌的田菁长势及降盐肥田效果更好：地上部生物量增加26.1%，根部增重46.2%，降盐效果比不接种根瘤菌的田菁提高20%~25%，土壤盐浓度比空白地降低74%~79%。相比空地，接菌处理的土壤速效氮、速效钾、速效磷含量分别增长29.12%、32.47%、29.91%。综上表明田菁与本研究筛选的土著高效共生固氮根瘤菌形成的共生固氮体系在黄河三角洲的盐碱地改良应用效果良好，并有望推广应用。
其他摘要	Sesbania cannabinais an excellent leguminous crop for saline-alkaline soil amelioration. Inculation with high-efficient rhzibia will promote the plant growth and is promising to improve the saline-alkaline soil amelioration. The nodules of S. cannabina were collected from 5 sampling sites in Yellow River delta and 2 sampling sites in the tidal flat of Rudong County，which is one of the introduction area of S. cannabina to North China. 198 strains were isolated and purified. We analysed the genetic diversity, species composition and correlation with soil factors of the S. cannabina rhizobia. 18 representative isolates were classified according to sequence analysis of recA gene and used for further genetic diversity and phylogenetic analyses based on 16S rRNA gene, housekeeping genes (recA, atpD and glnII) and symbiotic genes (nodA and nifH). In the Yellow River, all the isolates were cataloged into 9 genospecies: E. meliloti, R. pusense, N. huautlense and undefined Ensifer sp. I, Ensifer sp. II, Ensifer sp. III, Rhizobium sp. I, Rhizobium sp. II, “Sesbanrhizobium” sp..Ensifer sp. I was the dominant group, occupying 71%. In the tidal of Rudong County, all the isolates were classified into E. meliloti, E. sesbania, N. huautlense, Ensifer sp. I, Rhizobium sp. I. E. meliloti and N. huautlense were the dominant groups, occupying 45%, 42%, respectively. The species composition of S. cannabina rhizobia in the Yellow River has changed dramatically compared with that of Rudong County, which indicated the distribution of S. cannabina rhizobia showed biogeographic characteristics. pH showed significantly positive correlation with the genetic diversity (P＜0.05). And within a certain range, the genetic diversity tended to be higher as the pH of soil increased.The salt content and available P of soil were determined as the significant factors for distribution of S. cannabina rhizobia. The phylogenies of nodA and nifH demonstrated the possible lateral of symbiltic genes. And in this way, some rhizobia adapted to local soil types or ecoregions developed their nodulation ability on S. cannabina. In plant inoculation assay of greenhouse, all the representive isolate could form nodules with S. cannabina. Ensifer sp. I YIC4027 showed the best growth-promoting efficiency, excellent nodulation and nitrogen fixation ability and aline-alkaline tolerance，which was chosed as rhizobia inoculator to S. cannabina in the further plot experiments in the Yellow River delta. The plot experiments indicated that compared to the S. cannabina without Ensifer sp. IYIC4027 inoculant, the fresh shoot and root weights increased significantly by 46.2% and 26.1%, respectively. And the soil salt content decreased by 20%~25%. Compared to the blank field, the soil salt content decreased with a 64%~79% drop from 0.46% to 0.12% and the content of available N, available K, available P in the soil increased by 29.12%, 32.47%, 29.91%, respectively.In conclusion, S. cannabina inoculated with high efficient symbiotic rhizobia Ensifer sp. I YIC4027 performed well in saline-alkaline soil amelioration in the Yellow River Delta, which is promising for widespread applications.
语种	中文
文献类型	学位论文
条目标识符	http://ir.yic.ac.cn/handle/133337/7932
专题	中国科学院烟台海岸带研究所知识产出_学位论文
作者单位	1.中科院烟台海岸带研究所 2.中国科学院大学
推荐引用方式 GB/T 7714	李项岳. 黄河三角洲田菁根瘤菌遗传多样性、高效菌株筛选及应用[D]. 北京. 中国科学院研究生院,2015.

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