Rj (rj) genes involved in nitrogen-fixing root nodule formation in soybean |
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| Authors: | Masaki Hayashi Yuichi Saeki Michiyo Haga Kyuya Harada Hiroshi Kouchi Yosuke Umehara |
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| Institution: | 1.National Institute of Agrobiological Sciences, 2-1-2 Kannondai, Tsukuba, Ibaraki 305-8602, Japan;2.Faculty of Agriculture, Miyazaki University, 1-1 Gakuen Kibanadai-Nishi, Miyazaki, Miyazaki 889-2192, Japan;3.Fukushima Prefecture Ken-chu Agriculture and Forestry Office, 1-1-1 Hayama, Koriyama, Fukushima 963-8540, Japan |
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| Abstract: | It has long been known that formation of symbiotic root nodules in soybean (Glycine max (L.) Merr.) is controlled by several host genes referred to as Rj (rj) genes, but molecular cloning of these genes has been hampered by soybean’s complicated genome structure and large genome size. Progress in molecular identification of legume genes involved in root nodule symbiosis have been mostly achieved by using two model legumes, Lotus japonicus and Medicago truncatula, that have relatively simple and small genomes and are capable of molecular transfection. However, recent development of resources for soybean molecular genetic research, such as genome sequencing, large EST databases, and high-density linkage maps, have enabled us to isolate several Rj genes. This progress has been achieved in connection with systematic utilization of the information obtained from molecular genetics of the model legumes. In this review, we summarize the current status of knowledge of host-controlled nodulation in soybean based on information from recent studies on Rj genes, and discuss the future research prospects. |
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| Keywords: | soybean root nodule symbiosis Rj (rj) gene host-controlled nodulation host-restriction of nodulation autoregulation of nodulation model legume |
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