Lemaire Benny, Dlodlo Oscar, Chimphango Samson, Stirton Charles, Schrire Brian, Boatwright James S, Honnay Olivier, Smets Erik, Sprent Janet, James Euan K, Muasya Abraham M
Department of Biological Sciences, University of Cape Town, Private Bag X3, Rondebosch 7701, Cape Town, South Africa Plant Conservation and Population Biology, KU Leuven, Kasteelpark Arenberg 31, PO Box 2435, 3001 Heverlee, Belgium
Department of Biological Sciences, University of Cape Town, Private Bag X3, Rondebosch 7701, Cape Town, South Africa.
FEMS Microbiol Ecol. 2015 Feb;91(2):1-17. doi: 10.1093/femsec/fiu024. Epub 2014 Dec 8.
Rhizobial diversity and host preferences were assessed in 65 native Fynbos legumes of the papilionoid legume tribes Astragaleae, Crotalarieae, Genisteae, Indigofereae, Millettieae, Phaseoleae, Podalyrieae, Psoraleeae and Sesbanieae. Sequence analyses of chromosomal 16S rRNA, recA, atpD and symbiosis-related nodA, nifH genes in parallel with immunogold labelling assays identified the symbionts as alpha- (Azorhizobium, Bradyrhizobium, Ensifer, Mesorhizobium and Rhizobium) and beta-rhizobial (Burkholderia) lineages with the majority placed in the genera Mesorhizobium and Burkholderia showing a wide range of host interactions. Despite a degree of symbiotic promiscuity in the tribes Crotalarieae and Indigofereae nodulating with both alpha- and beta-rhizobia, Mesorhizobium symbionts appeared to exhibit a general host preference for the tribe Psoraleeae, whereas Burkholderia prevailed in the Podalyrieae. Although host genotype was the main factor determining rhizobial diversity, ecological factors such as soil acidity and site elevation were positively correlated with genetic variation within Mesorhizobium and Burkholderia, respectively, indicating an interplay of host and environmental factors on the distribution of Fynbos rhizobia.
对蝶形花科黄芪族、猪屎豆族、染料木族、木蓝族、崖豆族、菜豆族、补骨脂族、灰毛豆族和田菁族的65种本土开普植物区系豆科植物的根瘤菌多样性和宿主偏好进行了评估。通过对染色体16S rRNA、recA、atpD以及与共生相关的nodA、nifH基因进行序列分析，并结合免疫金标记试验，确定共生菌为α-根瘤菌（固氮根瘤菌属、慢生根瘤菌属、剑菌属、中生根瘤菌属和根瘤菌属）和β-根瘤菌（伯克霍尔德菌属）谱系，其中大多数属于中生根瘤菌属和伯克霍尔德菌属，并表现出广泛的宿主相互作用。尽管猪屎豆族和木蓝族存在一定程度的共生混杂现象，即与α-和β-根瘤菌都能形成根瘤，但中生根瘤菌共生菌似乎对补骨脂族表现出普遍的宿主偏好，而伯克霍尔德菌则在灰毛豆族中占主导地位。虽然宿主基因型是决定根瘤菌多样性的主要因素，但土壤酸度和海拔高度等生态因素分别与中生根瘤菌属和伯克霍尔德菌属内的遗传变异呈正相关，这表明宿主和环境因素在开普植物区系根瘤菌的分布上存在相互作用。
