稻瘟病菌无毒基因AvrPiz-t编码了一个包含108个氨基酸的未知功能的预测分泌蛋白,其与对应的水稻抗稻瘟病基因Piz-t介导了基因对基因的抗病反应。序列分析发现AvrPiz-t的预测成熟蛋白AvrPiz-t90含有4个半胱氨酸残基,推测它们可能参与了AvrPiz-t蛋白分子内或分子间的相互作用。为了检测这4个半胱氨酸对AvrPiz-t功能的影响,利用定点突变技术对4个半胱氨酸残基分别进行了位点突变并构建了相应的稻瘟病菌互补载体。功能互补分析发现,上述4个突变体都丧失了AvrPiz-t无毒基因的功能。由此推断,半胱氨酸对AvrPiz-t蛋白功能的表达是非常重要的。
Abstract
The Magnaporthe oryzae avirulence gene AvrPiz-t encodes a small predicted secreted protein (108 amino acids) without known function and mediates resistance in a gene-for-gene fashion to Piz-t in rice. Sequence analysis of AvrPiz-t revealed that its predicted mature form AvrPiz-t90 consists of 4 cysteine residues, which is predicted to be involved in intra- and intermolecular interactions. To further investigate the significance of these 4 cysteine residues in the function of AvrPiz-t, a site-mutagenesis approach was utilized to ge-nerate 4 constructs encompassing mutations at each cysteine residue. Complementation tests revealed that these 4 derived AvrPiz-t mutants lost avirulence function to Piz-t, which indicated that these 4 cysteine residues were critical for the avirulence function of AvrPiz-t.
关键词
稻瘟病菌 /
无毒基因 /
半胱氨酸 /
致病性
{{custom_keyword}} /
Key words
Magnaporthe oryzae /
avirulent gene /
cysteine residue /
pathogenicity
{{custom_keyword}} /
{{custom_sec.title}}
{{custom_sec.title}}
{{custom_sec.content}}
参考文献
[1] Liu J, Wang X, Mitchell T, et al. Recent progress and understanding of the molecular mechanisms of the rice-Magnaporthe oryzae interaction [J]. Mol. Plant Pathol., 2010, 11(3): 419-427.
[2] Baker B, Zambryski P, Staskawicz B, et al. Signaling in plant-microbe interactions [J]. Science, 1997, 276(5313): 726-733.
[3] Flor H H. Current status of the gene-for-gene concept [J]. Annual Review of Phytopathology, 1971, 9275-9296.
[4] Silué D, Notteghem J L,Tharreau D. Evidence of a gene-for-gene relationship in the Oryza sativa-Magnaporthe grisea pathosystem [J]. Phytopathology, 1992, 82577-82580.
[5] Kang S, Sweigard J A,Valent B. The PWL host specificity gene family in the blast fungus Magnaporthe grisea [J]. Mol. Plant Microbe Interact, 1995, 8(6): 939-948.
[6] Sweigard J A, Carroll A M, Kang S, et al. Identification, cloning, and characterization of PWL2, a gene for host species specificity in the rice blast fungus [J]. Plant Cell, 1995, 7(8): 1221-1233.
[7] Orbach M J, Farrall L, Sweigard J A, et al. A telomeric avirulence gene determines efficacy for the rice blast resistance gene Pi-ta [J]. Plant Cell, 2000, 12(11): 2019-2032.
[8] Farman M L, Eto Y, Nakao T, et al. Analysis of the structure of the AVR1-CO39 avirulence locus in virulent rice-infecting isolates of Magnaporthe grisea [J]. Mol. Plant Microbe Interact, 2002, 15(1): 6-16.
[9] Bohnert H U, Fudal I, Dioh W, et al. A putative polyketide synthase/peptide synthetase from Magnaporthe grisea signals pathogen attack to resistant rice [J]. Plant Cell, 2004, 16(9): 2499-2513.
[10]Li W, Wang B, Wu J, et al. The Magnaporthe oryzae avirulence gene AvrPiz-t encodes a predicted secreted protein that triggers the immunity in rice mediated by the blast resistance gene Piz-t [J]. Mol. Plant Microbe Interact, 2009, 22(4): 411-420.
[11]Yoshida K, Saitoh H, Fujisawa S, et al. Association genetics reveals three novel avirulence genes from the rice blast fungal pathogen Magnaporthe oryzae [J]. Plant Cell, 2009, 21(5): 1573-1591.
[12]Talbot N J, Ebbole D J,Hamer J E. Identification and characterization of MPG1, a gene involved in pathogenicity from the rice blast fungus Magnaporthe grisea [J]. Plant Cell, 1993, 5(11): 1575-1590.
[13]Saghai-Maroof M A, Soliman K M, Jorgensen R A, et al. Ribosomal DNA spacer-length polymorphisms in barley: mendelian inheritance, chromosomal location, and population dynamics [J]. Proc. Natl. Acad. Sci. U S A, 1984, 81(24): 8014-8018.
{{custom_fnGroup.title_cn}}
脚注
{{custom_fn.content}}
基金
国家自然科学基金资助项目(30971878); 浙江大学自主计划青年资助项目(2009QNA6024)
{{custom_fund}}