Rice stripe disease, caused by rice stripe virus (RSV), is one of the major virus diseases in east Asia. Rice plants infected with RSV usually show symptoms such as chlorosis, weakness, necrosis in newly emerged leaves and stunting. To reveal rice cellular systems influenced by RSV infection, temporal changes in the transcriptome of RSV-infected plants were monitored by a customized rice oligoarray system. The transcriptome changes in RSV-infected plants indicated that protein-synthesis machineries and energy production in the mitochondrion were activated by RSV infection, whereas energy production in the chloroplast and synthesis of cell-structure components were suppressed. The transcription of genes related to host-defence systems under hormone signals and those for gene silencing were not activated at the early infection phase. Together with concurrent observation of virus concentration and symptom development, such transcriptome changes in RSV-infected plants suggest that different sets of various host genes are regulated depending on the development of disease symptoms and the accumulation of RSV.
INTRODUCTIONRice stripe disease is the most severe virus disease of rice in east Asia. Typical symptoms are chlorosis and weakness on newly emerged leaves. The plant becomes considerably stunted when affected at the early growth stages (Ou, 1972). Rice stripe disease also causes necrosis of newly emerged leaves (Takahashi et al., 1991). The causal virus is Rice stripe virus (RSV), which belongs to the genus Tenuivirus (Falk & Tsai, 1998). RSV is transmitted by small brown planthopper (SBPH; Laodelphax striatellus), Terthron albovittatum, Unkanodes sapporonus and Unkanodes albifascia (Falk & Tsai, 1998;Ou, 1972). RSV has a thin, filamentous shape and no envelope. The genome consists of four single-stranded RNA segments; RNA1 is negative-sense and RNAs 2-4 are ambisense. Viral mRNAs transcribed from viral RNA or viral cRNA by RNA-dependent RNA polymerase are released to the cytoplasm. Subsequently, a 59-capped short ribonucleotide leader cleaved from the host mRNA is added to the viral mRNAs by cap-snatching. The 59-capped RSV RNA is transcribed efficiently in host cells (Falk & Tsai, 1998;Shimizu et al., 1996). Genes encoding a gene-silencing suppressor and movement proteins were also identified in the RSV genome (Lu et al., 2009;Xiong et al., 2008Xiong et al., , 2009. Although extensive functional analysis of the RSV genome has been conducted, there have been no reports on the interaction between RSV and rice plants, which may clarify the mechanisms behind the appearance of disease symptoms.Rice is a model cereal plant, for which many genomic and transcriptome resources and tools are already available (Liang et al., 2008;Ouyang et al., 2007; Rice Annotation Project, 2008; Rice Full-length cDNA Consortium, 2003). The elucidation of genome sequences and structures in diverse organisms has led to the development of various high-throughput genome and transcriptome analytical tools. Numerous transcriptome profiles in...
