Rice black-streaked dwarf virus (RBSDV) is a recognized member of the genus Fijivirus,family Reoviridae.Its genome has ten double-stranded RNA (dsRNA) segments (S1-S10),in which the fifth genome segment (S5) contains two open reading frames (ORFs) with a partially overlapping region.The second ORF of RBSDV S5 encodes a viral nonstructural protein named p5b with unknown function.To reveal the function of p5b,its gene was ligated into the bait plasmid pGBKT7 and an expression library containing rice cDNAs was constructed using plasmid pGADT7 for yeast two-hybrid assay.The bait protein p5b was detected in yeast by western blot,and the result of an auto-activation test showed that p5b could not autonomously activate the expression of reporter genes in yeast.Then the bait protein p5b was used for screening the cDNA expression libraries of rice.Gene fragments of some pivotal enzymes involved in photosynthesis,respiration and other important metabolic processes,were identified to interact with p5b in yeast,suggesting that these interactions may play roles in symptom development in infected plants.
