A N2-fixing endophytic Burkholderia sp associated with maize plants cultivated in Mexico
A N2-fixing endophytic Burkholderia sp associated with maize plants cultivated in Mexico
复制标题
DOI：
10.1139/w02-023
复制
发表时间：
2002-04-01
影响因子：
2.8
通讯作者：
Caballero-Mellado, J
中科院分区：
文献类型：
--
作者：
Estrada, P;Mavingui, P;Caballero-Mellado, J
在与玉米相关的潜在内生固氮伯克霍尔德氏菌的调查框架内，对其原产国墨西哥瓦哈卡州附近的一块本地玉米地的土壤进行了研究。在实验室条件下，以两个古玉米品种的苗木为诱捕器，从土壤样品中筛选出内生菌候选菌株。在从植物体内分离的能够在PCAT培养基上生长的N-2固定剂中，最丰富的菌株属于伯克霍尔德氏菌属(API 20NE，RRS序列)。从不同植物的根和地上部获得的代表性菌株表现出相同的(RRS和nifH RFLP)，表明它们是密切相关的。此外，它们的16S rDNA序列与已描述的伯克霍尔德氏菌不同，在系统发育上，它们构成了伯克霍尔德氏菌属一个独立的深分支新谱系。这表明这些分离物可能构成了一个新种。接种实验证实，这些固氮伯克霍尔德氏菌能够在玉米植株组织中密集定殖。随后从大田种植的玉米和teosinte植物中获得了更多这一组的分离物。据推测，该物种的菌株已经与它们的寄主植物之一teosinte发展了一种原始的共生关系，这种共生关系在teosinte驯化成玉米的过程中持续存在。
In the frame of a survey of potentially endophytic N-2-fixing Burkholderia associated with maize in Mexico, its country of origin, the soil of an indigenous maize field near Oaxaca was studied. Under laboratory conditions, plant seedlings of two ancient maize varieties were used as a trap to select endophyte candidates from the soil sample. Among the N-2 fixers isolated from inside plant tissues and able to grow on PCAT medium, the most abundant isolates belonged to genus Burkholderia (API 20NE, rrs sequences). Representative isolates obtained from roots and shoots of different plants appeared identical (rrs and nifH RFLP), showing that they were closely related. In addition, their 16S rDNA sequences differed from described Burkholderia species and, phylogenetically, they constituted a separate deep-branching new lineage in genus Burkholderia. This indicated that these isolates probably constituted a new species. An inoculation experiment confirmed that these N-2-fixing Burkholderia isolates could densely colonize the plant tissues of maize. More isolates of this group were subsequently obtained from field-grown maize and teosinte plants. It was hypothesized that strains of this species had developed a sort of primitive symbiosis with one of their host plants, teosinte, which persisted during the domestication of teosinte into maize.