LOX genes in blast fungus (Magnaporthe grisea) resistance in rice
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Plant Lipoxygenases (LOX) are known to play major role in plant immunity by providing front-line defense against pathogen-induced injury. To verify this, we isolated a full-length OsLOX3 gene and also 12 OsLOX cDNA clones from Oryza sativa indica (cultivar Pusa Basmati 1). We have examined the role played by LOXs in plant development and during attack by blast pathogen Magnaporthe grisea. Gene expression, promoter region analysis, and biochemical and protein structure analysis of isolated OsLOX3 revealed significant homology with LOX super family. Protein sequence comparison of OsLOXs revealed high levels of homology when compared with japonica rice (up to100%) and Arabidopsis (up to 64%). Isolated LOX3 gene and 12 OsLOX cDNAs contained the catalytic LOX domains much required for oxygen binding and synthesis of oxylipins. Amino acid composition, protein secondary structure, and promoter region analysis (with abundance of motifs CGTCA and TGACG) support the role of OsLOX3 gene in providing resistance to diseases in rice plants. OsLOX3 gene expression analysis of root, shoot, flag leaf, and developing and mature seed revealed organ specific patterns during rice plant development and gave evidence to association between tissue location and physiological roles played by individual OsLOXs. Increased defense activity of oxylipins was observed as demonstrated by PCR amplification of OsLOX3 gene and upon inoculation with virulent strains of M. grisea and ectopic application of methyl jasmonate in the injured leaf tissue in adult rice plants.
KeywordsLipoxygenase Rice Blast disease Defense response Methyl jasmonate Expression
The authors are grateful to Bioinformatics Information Network under Department of Biotechnology, Government of India for grant provided to support experimental costs and fellowship to VKS. Also, the authors are thankful to B. Murugan and A. Dev for help in disease inoculation experiments in the green house and to Department of Molecular Biology and Genetic engineering, G.B. Pant University of Agriculture and Technology, Pantngar, India for providing all laboratory and green house facilities.
- Bailey TM, Elkan C (1994) Fitting a mixture model by expectation maximization to discover motifs in biopolymers. In: Proceedings of the Second International Conference on Intelligent Systems for Molecular Biology. AAAI Press, Menlo Park, California, pp. 28–36Google Scholar
- Després C, Chubak C, Rochon A, Clark R, Bethune T, Desveaux D, Fobert PR (2003) The Arabidopsis NPR1 disease resistance protein is a novel cofactor that confers redox regulation of DNA binding activity to the basic domain/leucine zipper transcription factor TGA1. Plant Cell 15:2181–2191PubMedCrossRefGoogle Scholar
- Griffiths A, Barry C, Alpuche-Solis AG, Grierson D (1999) Ethylene and developmental signals regulate expression of lipoxygenase genes during tomato fruit ripening. J Exp Bot 50:793–798Google Scholar
- Porta H, Rueda-Benítez P, Campos F, Colmenero-Flores JM, Colorado JM, Carmona MEJ, Covarrubias AA, Rocha-Sosa M (1999) Analysis of lipoxygenase mRNA accumulation in the common bean (Phaseolus vulgaris L.) during development and under stress conditions. Plant Cell Physiol 40(8):850–858PubMedCrossRefGoogle Scholar
- Solovyev V, Kosarev P, Seledsov I, Vorobyev D (2006) Automatic annotation of eukaryotic genes, pseudogenes and promoters. Genome Biol 7 Suppl 1(S10):1–12Google Scholar
- Vellosillo T, Martínez M, López MA, Jorge Vicente J, Cascón T, Dolan L, Hamberg M, Castresana C (2007) Oxylipins produced by the 9-lipoxygenase pathway in Arabidopsis regulate lateral root development and defense responses through a specific signaling cascade. Plant Cell 19:831–846PubMedCrossRefGoogle Scholar