Diversity among Bradyrhizobium isolates nodulating yardlong bean and sunnhemp in Guam
Diversity among Bradyrhizobium isolates nodulating yardlong bean and sunnhemp in Guam
复制标题
关岛慢生根瘤菌分离物结瘤豆和荠麻的多样性
DOI：
--
复制
发表时间：
2002
影响因子：
4
通讯作者：
D. Borthakur
中科院分区：
文献类型：
--
作者：
Z. You;M. Marutani;D. Borthakur
目的：分离和表征关岛使长豆和太阳麻结瘤的缓生根瘤菌。
方法和结果：检查了关岛结瘤豆和太阳麻的慢生根瘤菌种群的遗传多样性及其与日本慢生根瘤菌和 B. elkanii 参考菌株的相关性。 58 个慢生根瘤菌分离株的基因组 DNA。与 B. japonicum nodY 和 B. elkanii nodK 基因杂交。根据杂交模式，分离株分为三个 nodY-nodK 杂交组。第 I 组包含大部分分离株并与 nodY 杂交，而第 II 组分离株与 nodK 杂交。第三组分离株不与 nodY 或 nodK 杂交，在豇豆上形成固氮根瘤，但没有在大豆上结瘤。对一些 III 组分离株的 16S rRNA 基因可变区 280 bp 片段的 DNA 序列分析表明，这些分离株与慢生根瘤菌属 (Bradyrhizobium spp) 更相似。比 B. japonicum 或 B. elkanii 更有效。
结论：关岛大部分结瘤豆和荠麻分离株与日本芽孢杆菌相似，但也有一些分离株与慢生根瘤菌相似。使包括豇豆在内的多种豆类结节。
研究的意义和影响：由于长豆和荠麻都是由一系列缓生根瘤菌结瘤的，因此可以根据两种豆科植物的结瘤效果来选择优良菌株。
Aims: To isolate and characterize bradyrhizobia that nodulate yardlong bean and sunnhemp in Guam.
Methods and Results: Bradyrhizobia populations that nodulate yardlong bean and sunnhemp in Guam were examined for genetic diversity and their relatedness to Bradyrhizobium japonicum and B. elkanii reference strains. Genomic DNA of 58 isolates of Bradyrhizobium spp. was hybridized with B. japonicum nodY and B. elkanii nodK genes. Based on the hybridization patterns, the isolates were classified into three nodY‐nodK hybridizing groups. Group I comprised the majority of the isolates and hybridized with nodY whereas group II isolates hybridized with nodK. The group III isolates, that did not hybridize with either nodY or nodK, formed nitrogen‐fixing nodules on cowpea but did not nodulate soybean. DNA sequence analysis of a 280‐bp fragment of the variable region of the 16S rRNA gene of a few group III isolates showed that these isolates were more similar to Bradyrhizobium spp. than to B. japonicum or B. elkanii.
Conclusions: The majority of the isolates nodulating yardlong bean and sunnhemp in Guam are similar to B. japonicum, although some isolates are similar to Bradyrhizobium spp. that nodulate a miscellaneous group of legumes including cowpea.
Significance and Impact of the Study: Since both yardlong bean and sunnhemp are nodulated by a range of bradyrhizobia, selection of superior strains may be based on nodulation effectiveness on both legumes.