title: Phytosulfokine Is Involved in Positive Regulation of Lotus japonicus Nodulation.
abstract: Phytosulfokine (PSK) is a tyrosine-sulfated peptide that is widely distributed in plants, participating in cell proliferation, differentiation, and innate immunity. The potential role of PSK in nodulation in legumes has not been reported. In this work, five PSK precursor genes were identified in Lotus japonicas, designated as LjPSK1 to LjPSK5. Three of them (LjPSK1, LjPSK4, and LjPSK5) were found to be expressed in nitrogen-fixing root nodules. LjPSK1 and LjPSK4 were not induced at the early stage of nodulation. Interestingly, while the expression of LjPSK4 was also found in spontaneous nodules without rhizobial colonization, LjPSK1 was not induced in these pseudo nodules. Promoter-β-glucuronidase analysis revealed that LjPSK1 was highly expressed in enlarged symbiotic cells of nodules. Exogenous addition of 1 1M synthetic PSK peptide resulted in increased nodule numbers per plant. Consistently, the number of mature nodules but not the events of rhizobial infection and nodule initiation was increased by overexpressing LjPSK1 in transgenic hairy roots, in which the expression of jasmonate-responsive genes was found to be repressed. These results suggest that PSK is a new peptide signal that regulates nodulation in legumes, probably through cross-talking with other phytohormones.
authors.affiliation: 1 Shanghai Key Lab of Bio-energy Crops, School of Life Sciences, Shanghai University, Shanghai, 200444, China;|2 State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan 430070, China;|3 State Key Lab of Plant Molecular Genetics, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, 200032, China;
authors.forename: Chao
authors.initials: C
authors.lastname: Wang
authors.affiliation: 2 State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan 430070, China;
authors.forename: Haixiang
authors.initials: H
authors.lastname: Yu
authors.affiliation: 2 State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan 430070, China;
authors.forename: Zhongming
authors.initials: Z
authors.lastname: Zhang
authors.affiliation: 1 Shanghai Key Lab of Bio-energy Crops, School of Life Sciences, Shanghai University, Shanghai, 200444, China;
authors.forename: Liangliang
authors.initials: L
authors.lastname: Yu
authors.affiliation: 3 State Key Lab of Plant Molecular Genetics, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, 200032, China;
authors.forename: Xiaoshu
authors.initials: X
authors.lastname: Xu
authors.affiliation: 4 Department of Plant, Soil, and Entomological Sciences and Program of Microbiology, Molecular Biology and Biochemistry, University of Idaho, Moscow, ID 83844, U.S.A.
authors.forename: Zonglie
authors.initials: Z
authors.lastname: Hong
authors.affiliation: 1 Shanghai Key Lab of Bio-energy Crops, School of Life Sciences, Shanghai University, Shanghai, 200444, China;
authors.forename: Li
authors.initials: L
authors.lastname: Luo
mesh_terms: D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000235:genetics / Q000378:metabolism; D003517:Cyclopentanes / Q000378:metabolism / Q000494:pharmacology; D018506:Gene Expression Regulation, Plant / Q000187:drug effects; D005966:Glucuronidase / Q000235:genetics; D000070116:Lotus / Q000235:genetics* / Q000382:microbiology; D008969:Molecular Sequence Data; D054883:Oxylipins / Q000378:metabolism / Q000494:pharmacology; D036361:Peptide Hormones / Q000235:genetics; D010940:Plant Proteins / Q000235:genetics* / Q000378:metabolism; D030821:Plants, Genetically Modified; D011401:Promoter Regions, Genetic; D012231:Rhizobium / Q000502:physiology; D053204:Root Nodules, Plant / Q000235:genetics* / Q000254:growth & development / Q000382:microbiology; D017386:Sequence Homology, Amino Acid; D013559:Symbiosis / Q000235:genetics
chemical_list: D003517:Cyclopentanes; D054883:Oxylipins; C101483:PSK-beta protein, plant; D036361:Peptide Hormones; D010940:Plant Proteins; C011006:jasmonic acid; D005966:Glucuronidase