Poster: Molecular & Cellular Plant-Microbe Interactions: Proteomics/Metabolomics/Genomics
Replication and transcription are independently modulated for each Banana bunchy top virus DNA component
N. YU (1), H. Xie (1), J. Wang (1), X. Zhang (1), Z. Liu (1), Z. Xiong (2) (1) Institute of Tropical Bioscience and Biotechnology, Chinese Academy of Tropical Agricultural Sciences, China; (2) University of Arizona, U.S.A.
Banana bunchy top virus (BBTV) causes a severe disease in banana world-wide. BBTV is a single-stranded DNA virus with a genome consisting of six circular molecules of ~1kb each. Some BBTV isolates also carry satellite DNA molecules that are not essential for BBTV infection. To understand the coordinated actions of the multiple genomic components during BBTV infection, we measured the relative and absolute amounts of each DNA component of isolate B2 and its transcript levels by real-time PCR (qPCR) and reverse transcription (RT)-qPCR, respectively. Significant differences in the absolute amounts and expression levels were found among BBTV genomic components. The most abundant DNA molecules are those of DNA-U3, DNA-M, and DNA-N, 4 to 6 times more than those of DNA-R. The least abundant DNA molecules are those of DNA-C, 12 times less than that of DNA-U3. Interestingly, two satellite DNA components are also present at high levels, with amounts similar to that of DNA-U3. Transcript levels determined by RT-qPCR did not correspond to the absolute amount of each DNA component. The most abundant transcripts came from DNA-N, followed by DNA-U3, and DNA-S, and the least abundant transcripts came from DNA-C, 110-fold less than those from DNA-N. The ratios of transcript copies over DNA copies ranged from 0.15 to 2.63. These data suggest that both replication and expression levels are independently modulated for each DNA component, possibly by cis-acting DNA sequence elements.