Production of cecropin A in transgenic rice plants has an impact on host gene expression.
Expression of the cecropin A gene in rice confers resistance to the rice blast fungus Magnaporthe oryzae. In this study, a polymerase chain reaction-based suppression subtractive hybridization approach was used to generate a cDNA macroarray from the elite japonica rice (Oryza sativa L.) cultivar 'Senia'. Gene expression studies revealed that the expression of components of the protein secretory and vesicular transport machinery is co-ordinately activated at the pre-invasive stage of infection of rice by the blast fungus. Comparisons of gene expression between wild-type and cecropin A plants revealed the over-expression of genes involved in protection against oxidative stress in transgenic plants in the absence of the pathogen, which correlated well with the tolerance of these plants to oxidative stress. A subcellular fractionation analysis suggested that cecropin A accumulates in the endoplasmic reticulum in cecropin A rice. Moreover, a large number of genes related to the processes of synthesis, folding and stabilization of proteins that enter into the secretory pathway are over-expressed in cecropin A rice, confirming that these plants constitutively express the unfolded protein response. Transgenic expression of cecropin A in rice has an effect on the transcriptional reprogramming that accompanies plant adaptation to fungal infection. Overall, this study provides evidence for transgene-induced changes in gene expression in cecropin A rice under both optimal growth conditions and stress conditions imposed by fungal infection. The data also indicate that resistance to blast in cecropin A rice may be the consequence of a combination of the antifungal activity of cecropin A and cecropin A-mediated over-expression of rice genes.
Campo
Sonia
S
Consorcio CSIC-IRTA Laboratorio de Genética Molecular Vegetal, Departamento de Genética Molecular, Instituto de Biología Molecular de Barcelona, CSIC, Jordi Girona 18, 08034 Barcelona, Spain.
Manrique
Silvia
S
García-Martínez
José
J
San Segundo
Blanca
B
D023181:Antimicrobial Cationic Peptides / Q000235:genetics / Q000378:metabolism*; D004721:Endoplasmic Reticulum / Q000378:metabolism; D020224:Expressed Sequence Tags; D018506:Gene Expression Regulation, Plant / Q000187:drug effects; D054884:Host-Pathogen Interactions; D006861:Hydrogen Peroxide / Q000494:pharmacology; D020082:Magnaporthe / Q000502:physiology; D020411:Oligonucleotide Array Sequence Analysis; D012275:Oryza / Q000235:genetics / Q000378:metabolism* / Q000382:microbiology; D010935:Plant Diseases / Q000235:genetics / Q000382:microbiology; D030821:Plants, Genetically Modified / Q000235:genetics / Q000378:metabolism* / Q000382:microbiology; D021381:Protein Transport
D023181:Antimicrobial Cationic Peptides; C031161:cecropin A; D006861:Hydrogen Peroxide