Identification of a major pathogenicity determinant and suppressors of RNA silencing encoded by a South Pacific isolate of Banana bunchy top virus originating from Pakistan

Abstract

Five genes encoded by Banana bunchy top virus (BBTV) originating from Pakistan were expressed in Nicotiana benthamiana using a Potato virus X (PVX) vector. Expression of the master replication-associated protein (mRep) and movement protein (MP) resulted in necrotic cell death of inoculated tissues, as well as leaf curling and necrosis along the veins in newly emerging leaves. The systemic necrosis induced by the expression of MP was discolored (dark) in comparison to that induced by mRep. Expression of the cell-cycle link protein (Clink), the coat protein (CP), and the nuclear shuttle protein from the PVX vector induced somewhat milder symptoms, consisting of mild leaf curling and mosaic, although expression of the CP caused a necrotic response in inoculated leaf. The accumulation of viral RNA was enhanced by MP, Clink, and CP. Of the five BBTV-encoded gene products two, the MP and Clink, stabilized GFP-specific mRNA and reduced GFP-specific small interfering RNA in N. benthamiana line 16c when expressed under the control of the 35S promoter and co-inoculated with a construct for the expression of GFP hairpin RNA construct. These results identified MP and Clink as suppressors of RNA silencing. Taken together the ability of MP to induce severe symptoms in plants and suppress RNA silencing implicates this product as a major pathogenicity determinant of BBTV.

βC1 of chili leaf curl betasatellite is a pathogenicity determinant

“…The N. benthamiana plants inoculated with pgR107 showed typical symptoms of systemic PVX infection (data not shown) as reported earlier [20]. However, inoculation of N. benthamiana with PVX C.βC1 resulted in typical disease symptoms of cotton leaf curl disease such as leaf curling and enations (Figure 1).…”

Molecular characterization of banana bunchy top virus isolate from Sri Lanka and its genetic relationship with other isolates

“…CP-mediated resistance was one of the most common pathogen derived resistance strategies employed against plant viruses and has proven success against many viruses [15]. However CP mediated resistance may only be effective against closely related viruses which share a high level of sequence homology [1,4,19,34,35]. High level of conservation of 96-100 % observed in the CP gene of BBTV isolates of South Pacific group analyzed in the present study suggests that any BBTV CP transgene on the South Pacific isolates likely to provide effective CP mediated resistance against South Pacific BBTV isolates including Sri Lankan isolate.…”

A transgenic approach to control hemipteran insects by expressing insecticidal genes under phloem-specific promoters

“…Fresh samples were taken from transgenic plants after washing with diethylpyrocarbonate (DEPC) and kept in liquid nitrogen. Total RNA from transgenic plants at the T 1 stage was extracted by using Plant RNA Purification Reagent (Invitrogen catalog number 12322-012) following a standard published protocol 75 . Freshly extracted RNA was quantified using a Nanodrop (Thermo Scientific, USA) and was used to synthesize cDNA with the cDNA Synthesis Kit (Thermo Scientific, USA).…”