ISSN 2326-7275
International Journal of Anatomy and Physiology ISSN 2326-7275 Vol. 10 (6), pp. 001-010, June, 2021. © International Scholars Journals
Full Length Research Paper
Characterization and monitoring of selected rhizobial strains isolated from tree legumes in Thailand
Monchai Manassila1, Achara Nuntagij2, Somsak Kotepong2, Nantakorn Boonkerd1, and Neung Teaumroong1*
1School of Biotechnology, Institute of Agricultural Technology, Suranaree University of Technology, Nakhonratchasima 30000, Thailand..
2Soil Mocrobiology Research Group, Soil Science Division, Department of Agriculture, Bangkok 10900, Thailand.
Accepted 26 May, 2021
Abstract
Tree legume rhizobia were isolated from five tree legumes; Acacia auriculaformis Cunn., A. mangium Willd., Milletia leucantha Kurz., Pterocarpus indicus Willd., and Xylia xylocarpa Taub. grown in Thailand. Forty four highly effective rhizobial strains were selected on the basis of nitrogenase activity, number of nodules and plant biomass. The selected strains were characterized in both terms of physiology and genetics. Most of the strains are slow grower and able to nodulate cowpea rather than soybean. In addition, IAA production could be detected only from few strains. When almost complete 16S rRNA sequences were analysed, the results indicated that most of the selected strains most likely belong to Bradyrhizobium elkanii and Bradyrhizobium sp. except strains AA67 and PT59 which most likely belong to B. japonicum. The nodule occupancy of selected strains in forest soil condition was investigated by using GUS reporter gene. The nodule occupancy is in the range of 63 - 100%. This suggests the appropriate strains should be produced as inoculum for further application in reforestation program-mes in Thailand.
Key words: Tree legume rhizobia, Acacia auriculaformis, Acacia mangium, Milletia leucantha, Pterocarpus indicus, Xylia xylocarpa.