Fig. 4

Infectivity and pathogenicity of the infectious clones of PEMV-1-YDL and PEMV-2-YDL. a Schematic diagram illustrating the one-step assembly cloning strategy used to construct infectious full-length cDNA clones of PEMV-1-YDL and PEMV-2-YDL. Three overlapping fragments of PEMV-1-YDL and PEMV-2-YDL were amplified and inserted into the linearized pCB301 vector. 35S, the cauliflower mosaic virus promoter; HDRz, hepatitis delta virus ribozyme; tNos, Nos terminator. b Symptoms of systemic leaves and pods of pea (Taiwan Changshou) plants PEMV-1-YDL or PEMV-2-YDL or mixture of PEMV-1-YDL and PEMV-2-YDL using agro-infiltration. Red arrows indicated enations on the systemic leaves and pods. Pea plants and pods were photographed at 21 and 33 days post-infection (dpi), respectively. The plants were inoculated with Agrobacteria that harbor the pCB301 vector as a control. c RT-PCR detection of PEMV-1-YDL and PEMV-2-YDL in the inoculated pea at 21 dpi. ‘-1’ and ‘-2’ indicated RT-PCR detection using specific primers of PEMV-1 (801 bp) and PEMV-2 (483 bp). Lane M, DL 2000 DNA Marker; lanes CB, plants inoculated with pCB301; lanes V1, plants inoculated with PEMV-1-YDL; lanes V2, plants inoculated with PEMV-2-YDL; lanes MV, plants inoculated with PEMV-1-YDL+PEMV-2-YDL; lanes NC, represent negative control. d Transmission electron micrograph of viral particles in the systemic leaves of pea plants inoculated with PEMV-1-YDL+PEMV-2-YDL via agro-infiltration. Bar = 200 nm