title: A nodule-specific plant cysteine proteinase, AsNODF32, is involved in nodule senescence and nitrogen fixation activity of the green manure legume Astragalus sinicus.
abstract: Asnodf32, encoding a nodule-specific cysteine proteinase in Astragalus sinicus, is probably involved in nodule senescence. To obtain direct evidence of its role in nodule senescence, Agrobacterium rhizogenes-mediated RNA interference was applied to A. sinicus hairy roots. Real-time qRT-PCR was used to estimate the efficiency of suppression. The senescent phenotype of transgenic nodules was examined with paraffin-embedded slides, TUNEL (TdT-mediated dUTP nick-end labeling) assay, and transmission electron microscopy, and the bacteroid nitrogen fixation activity was also measured. It was found that silencing of Asnodf32 delayed root nodule and bacteroid senescence. The period of bacteroid active nitrogen fixation was significantly extended. Interestingly, nodules enlarged in length were also observed on Asnodf32-silenced hairy roots. The results reported here indicate that Asnodf32 plays an important role in the regulation of root nodule senescence.
authors.affiliation: State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, Hubei, 430070, China.
authors.forename: Yixing
authors.initials: Y
authors.lastname: Li
authors.affiliation: State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, Hubei, 430070, China.
authors.forename: Lei
authors.initials: L
authors.lastname: Zhou
authors.affiliation: State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, Hubei, 430070, China.
authors.forename: Youguo
authors.initials: Y
authors.lastname: Li
authors.affiliation: State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, Hubei, 430070, China.
authors.forename: Dasong
authors.initials: D
authors.lastname: Chen
authors.affiliation: State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, Hubei, 430070, China.
authors.forename: Xuejuan
authors.initials: X
authors.lastname: Tan
authors.affiliation: State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, Hubei, 430070, China.
authors.forename: Lei
authors.initials: L
authors.lastname: Lei
authors.affiliation: State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, Hubei, 430070, China.
authors.forename: Junchu
authors.initials: J
authors.lastname: Zhou
mesh_terms: D027883:Astragalus Plant / Q000201:enzymology* / Q000382:microbiology / Q000502:physiology; D016922:Cellular Senescence; D003546:Cysteine Endopeptidases / Q000502:physiology*; D053938:DNA Fragmentation; D009586:Nitrogen Fixation / Q000502:physiology*; D010641:Phenotype; D010940:Plant Proteins / Q000037:antagonists & inhibitors / Q000502:physiology*; D034622:RNA Interference; D020133:Reverse Transcriptase Polymerase Chain Reaction; D053204:Root Nodules, Plant / Q000166:cytology* / Q000382:microbiology / Q000502:physiology
chemical_list: D010940:Plant Proteins; D003546:Cysteine Endopeptidases