Abstract Detail

Symbioses: Plant, Animal, and Microbe Interactions

Fujita, Marin [1], Hoshiyama, Miki [1], Yokoyama, Jun [2].

Analyses of rhizobial communities in root nodules of Japanese species of section Junceae (genus Lespedeza, Fabaceae).

The most conspicuous example of nitrogen-fixation symbiosis in land plants is the root nodule symbiosis between legume and rhizobia. Each legume species frequently establishes a specific mutualistic relationship with a particular rhizobial species or genera. In the case when closely related legume species grow sympatrically, how is the rhizobial composition of these species? Species of the section Junceae of genus Lespedeza. often grow together in the same habitat, and it can be a good candidate to compare rhizobial compositions among congeneric species. In previous studies in China, specificity to rhizobia was different among species of section Junceae. Thus, the effects of sympatry to rhizobial composition may be different among species. In this study, we compared the bacterial composition in the root nodules of four taxa of section Junceae, L. tomentosa, L. cuneata, L. c. var. serpens and L. pilosa, especially the places where these species grew sympatrically in Japan. Plants were collected from northern to western Honshu island. Bacterial strains were isolated from surface-sterilized nodules, and molecular identifications were conducted based on the partial sequence of 16SrRNA gene or PCR- RFLP of the gene. As a result, most of the rhizobia obtained from the species of section Junceae were Bradyrhizobium. Strains of Bradyrhizobium isolated from them were divided into two groups (hereafter, B. japonicum group and B. elkanii group) based on the phylogenetic analysis and these ratios were different among species and sampling points. Rhizobial strains isolated from L. pilosa were dominated by B. elkanii group in all sampling points, suggesting the apparent specificity to rhizobia. In the case of L. c. var. serpens, B. elkanii group dominated isolates from the plants of co-occurring points with L. pilosa. while B. japonicum group was obtained slightly more from the plants with L. cuneata. B. japonicum group accounted for over a half of isolates from L. cuneata at all but two sampling points, suggesting the preference to B. japonicum group. Although L. tomentosa was investigated for only a single population, frequencies of the groups were different between sampling times. From these results, several factors such as plant preference and environment in the soil may affect the dominance of Bradyrhizobium groups in the species of section Junceae. It is necessary to confirm the association between those factors and the dominance of the two rhizobial groups.

1 - Yamagata University, Faculty of Science, Kojirakawa1-4-12, Yamagata, 990-8560, Japan
2 - Yamagata University, Faculty Of Science, 1-4-12 Kojirakawa, Yamagata City, Yamagata, 06, 990-8560, Japan

Keywords:
Bradyrhizobium
Lespedeza
rhizobia
specificity.

Presentation Type: Poster
Session: P3, Symbioses: Plant, Animal, and Microbe Interactions Posters
Location: Virtual/Virtual
Date: Wednesday, July 21st, 2021
Time: 5:00 PM(EDT)
Number: P3SM009
Abstract ID:261
Candidate for Awards:None