Molecular analysis of three new receptor-like kinase genes from hexaploid wheat and evidence for their participation in the wheat hypersensitive response to stripe rust fungus infection.
Considerable progress has been made in understanding the function of receptor-like kinase (RLK) genes in model plants. However, much less is known about these genes in crop species. Here we report the characterization of three new wheat RLK genes (TaRLK-R1, 2 and 3). The primary structure of the putative proteins TaRLK-R1, 2 and 3 contained a signal peptide, a cysteine-rich extracellular domain, a transmembrane domain, and a predicted intracellular kinase domain. The fusions between TaRLK-R1, 2 or 3 and the green fluorescence protein (GFP) were targeted to the plasma membrane; such targeting required the signal peptide, extracellular domain and transmembrane domain. Transcription of TaRLK-R1, 2 and 3 was found mainly in the green organs, and was regulated by light. Transcript levels of TaRLK-R1, 2 and 3 increased during the hypersensitive reaction (HR) to stripe rust fungus. In addition, the TaRLK-R3 transcript level was also upregulated by abiotic stresses. Further experiments revealed that the recombinant kinase domain of TaRLK-R3 exhibited auto-phosphorylation activity in vitro. Knocking down the transcript levels of TaRLK-R1, 2 or 3 individually or all together by virus-induced gene silencing compromised the wheat HR to stripe rust fungus. The demonstration of TaRLK-R1, 2 and 3 as positive contributors in the wheat HR to stripe rust fungus suggests a new direction for further functional studies of this important family of RLK genes, and may facilitate the breeding of wheat varieties resistant to stripe rust disease.
Zhou
Huanbin
H
The State Key Laboratory of Plant Cell and Chromosome Engineering, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China.
Li
Shaofang
S
Deng
Zhiyong
Z
Wang
Xianping
X
Chen
Tao
T
Zhang
Jinsong
J
Chen
Shouyi
S
Ling
Hongqing
H
Zhang
Aimin
A
Wang
Daowen
D
Zhang
Xiangqi
X
D000595:Amino Acid Sequence; D001487:Basidiomycota / Q000254:growth & development / Q000276:immunology; D020868:Gene Silencing; D017343:Genes, Plant; D007113:Immunity, Innate; D008027:Light; D008969:Molecular Sequence Data; D009997:Osmotic Pressure; D018384:Oxidative Stress; D010766:Phosphorylation; D010770:Phosphotransferases / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D010802:Phylogeny; D010935:Plant Diseases / Q000276:immunology*; D010940:Plant Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D017346:Protein Serine-Threonine Kinases / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D011956:Receptors, Cell Surface / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D016415:Sequence Alignment; D014158:Transcription, Genetic; D014908:Triticum / Q000201:enzymology / Q000235:genetics* / Q000276:immunology / Q000382:microbiology
D010940:Plant Proteins; D011956:Receptors, Cell Surface; D011993:Recombinant Fusion Proteins; D010770:Phosphotransferases; D017346:Protein Serine-Threonine Kinases