jasmonic-acid and oryzemate

Plants exhibit resistance against incompatible pathogens, via localized and systemic responses as part of an integrated defense mechanism. To study the compatible and incompatible interactions between rice and bacteria, a proteomic approach was applied. Rice cv. Java 14 seedlings were inoculated with compatible (Xo7435) and incompatible (T7174) races of Xanthomonas oryzae pv. oryzae (Xoo). Cytosolic and membrane proteins were fractionated from the leaf blades and separated by 2-D PAGE. From 366 proteins analyzed, 20 were differentially expressed in response to bacterial inoculation. These proteins were categorized into classes related to energy (30%), metabolism (20%), and defense (20%). Among the 20 proteins, ribulose-1,5-bisphosphate carboxylase/oxygenase large subunit (RuBisCO LSU) was fragmented into two smaller proteins by T7174 and Xo7435 inoculation. Treatment with jasmonic acid (JA), a signaling molecule in plant defense responses, changed the level of protein accumulation for 5 of the 20 proteins. Thaumatin-like protein and probenazole-inducible protein (PBZ) were commonly up-regulated by T7174 and Xo7435 inoculation and JA treatment. These results suggest that synthesis of the defense-related thaumatin-like protein and PBZ are stimulated by JA in the defense response pathway of rice against bacterial blight.

Topics: Cluster Analysis; Cyclopentanes; Electrophoresis, Gel, Two-Dimensional; Oryza; Oxylipins; Plant Diseases; Plant Leaves; Plant Proteins; Proteomics; Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; Thiazoles; Up-Regulation; Xanthomonas

Plant roots have important roles not only in absorption of water and nutrients, but also in stress tolerance such as desiccation, salt, and low temperature. We have investigated stress-response proteins from rice roots using 2-dimensional polyacrylamide-gel electrophoresis and found a rice protein, RO-292, which was induced specifically in roots when 2-week-old rice seedlings were subjected to salt and drought stress. The full-length RO-292 cDNA was cloned, and was determined to encode a protein of 160 amino acid residues (16.9 kDa, pI 4.74). The deduced amino acid sequence showed high similarity to known rice PR10 proteins, OsPR10a/PBZ1 and OsPR10b. RO-292 mRNA accumulated rapidly upon drought, NaCl, jasmonic acid and probenazole, but not by exposure to low temperature or by abscisic acid and salicylic acid. The RO-292 gene was also up-regulated by infection with rice blast fungus. Interestingly, induction was observed almost exclusively in roots, thus we named the gene RSOsPR10 (root specific rice PR10). The present results indicate that RSOsPR10 is a novel rice PR10 protein, which is rapidly induced in roots by salt, drought stresses and blast fungus infection possibly through activation of the jasmonic acid signaling pathway, but not the abscisic acid and salicylic acid signaling pathway.

Topics: Abscisic Acid; Cyclopentanes; Disasters; DNA, Complementary; Gene Expression Regulation, Plant; Molecular Sequence Data; Mycoses; Oryza; Oxylipins; Plant Proteins; Plant Roots; RNA, Messenger; Salicylic Acid; Sequence Homology, Amino Acid; Sequence Homology, Nucleic Acid; Signal Transduction; Sodium Chloride; Thiazoles

The activation of mitogen-activated protein kinases (MAPKs) has been previously implicated in signal transduction during plant responses to pathogen attack as well as to various environmental stresses. We have isolated from rice a new MAPK cDNA, OsBIMK1 ( O ryza s ativa L. BTH-induced MAPK 1), which encodes a 369-amino-acid protein with moderate to high nucleotide sequence similarity to previously reported plant MAPK genes. OsBIMK1 contains all 11 of the MAPK conserved subdomains and the phosphorylation-activation motif, TEY. We analyzed in detail the expression of OsBIMK1 upon treatment with various chemical and biological inducers of resistance responses in rice and in both incompatible and compatible interactions between rice and Magnaporthe grisea. Expression of OsBIMK1 was activated rapidly upon treatment with benzothiadiazole (BTH) as well as with dichloroisonicotinic acid, probenazole, jasmonic acid and its methyl ester, Pseudomonas syringae pv. syringae, or wounding. Expression of OsBIMK1 was induced rapidly during the first 36 h after inoculation with M. grisea in BTH-treated rice seedlings and in an incompatible interaction between M. grisea and a blast-resistant rice genotype. BTH treatment induced a systemic activation of OsBIMK1 expression. These results suggest that OsBIMK1 plays an important role in rice disease resistance.

Topics: Acetates; Amino Acid Sequence; Base Sequence; Cloning, Molecular; Cyclopentanes; DNA, Complementary; Gene Expression Regulation, Enzymologic; Gene Expression Regulation, Plant; Immunity, Innate; Isonicotinic Acids; Magnaporthe; Mitogen-Activated Protein Kinases; Molecular Sequence Data; Oryza; Oxylipins; Phylogeny; Plant Diseases; Pseudomonas; Sequence Analysis, DNA; Sequence Homology, Amino Acid; Signal Transduction; Stress, Mechanical; Thiadiazoles; Thiazoles

The rice blast resistance gene Pib is a member of the nucleotide binding site (NBS) and leucine-rich repeat (LRR) class of plant disease resistance (R) genes and belongs to a small gene family. We describe here the isolation and characterization of a Pib homologue (PibH8), and extensive investigation of the expression of the Pib gene family (Pib, PibH8, HPibH8-1, HPibH8-2) under various environmental and chemical treatments. PibH8 shows 42% identity and 60% similarity to Pib and, like Pib, has a duplication of the kinase 1a, 2, and 3a motifs of the NBS region in the N-terminal half of the protein. Interestingly, genes of the Pib family exhibit a diurnal rhythm of expression. RNA gel blot analysis revealed that their expression was regulated dramatically by environmental signals. such as temperature, light and water availability. Their expression was also induced by chemical treatments, such as jasmonic acid, salicylic acid, ethylene and probenazole. Our findings suggest that expression of the Pib gene family is up-regulated by environmental conditions that would favour pathogen infection. This may reflect the evolution of anticipatory control of R gene expression.

Topics: Abscisic Acid; Amino Acid Sequence; Blotting, Northern; Carrier Proteins; Cyclopentanes; DNA, Complementary; Ethylenes; Gene Expression Regulation, Plant; Magnaporthe; Molecular Sequence Data; Oryza; Oxylipins; Phosphate-Binding Proteins; Plant Diseases; Plant Proteins; Protein Isoforms; RNA, Messenger; Salicylic Acid; Sequence Alignment; Sequence Analysis, DNA; Sequence Homology, Amino Acid; Sodium Chloride; Temperature; Thiazoles; Up-Regulation