Begomoviruses (family Geminiviridae) are single-stranded DNA viruses transmitted by the whitefly Bemisia tabaci. Many economically important diseases in crops are caused by begomoviruses, particularly in tropical and subtropical environments. These include the betasatellite-associated begomoviruses causing cotton leaf curl disease (CLCuD) that causes significant losses to a mainstay of the economy of Pakistan, cotton. RNA interference (RNAi) or gene silencing is a natural defense response of plants against invading viruses. In counter-defense, viruses encode suppressors of gene silencing that allow them to effectively invade plants. Here, we have analyzed the ability of the begomovirus Cotton leaf curl Multan virus (CLCuMV) and its associated betasatellite, Cotton leaf curl Multan β-satellite (CLCuMB) which, together, cause CLCuD, and the nonessential alphasatellite (Cotton leaf curl Multan alphasatellite [CLCuMA]) for their ability to suppress gene silencing in Nicotiana benthamiana. The results showed that CLCuMV by itself was unable to efficiently block silencing. However, in the presence of the betasatellite, gene silencing was entirely suppressed. Silencing was not affected in any way when infections included CLCuMA, although the alphasatellite was, for the first time, shown to be a target of RNA silencing, inducing the production in planta of specific small interfering RNAs, the effectors of silencing. Subsequently, using a quantitative real-time polymerase chain reaction assay and Northern blot analysis, the ability of all proteins encoded by CLCuMV and CLCuMB were assessed for their ability to suppress RNAi and the relative strengths of their suppression activity were compared. The analysis showed that the V2, C2, C4, and βC1 proteins exhibited suppressor activity, with the V2 showing the strongest activity. In addition, V2, C4, and βC1 were examined for their ability to bind RNA and shown to have distinct specificities. Although each of these proteins has, for other begomoviruses or betasatellites, been previously shown to have suppressor activity, this is the first time all proteins encoded by a geminiviruses (or begomovirus-betasatellite complex) have been examined and also the first for which four separate suppressors have been identified.

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The present study was aimed to assess drinking water quality regarding arsenic (As) and its impact on health from Mailsi (Punjab), Pakistan. Forty four groundwater samples were collected from two sites Sarganaand Mailsi. Arsenic and other cations were determined by atomic absorption spectrophotometer, whereas the anions were determined either through titration or spectrophotometer. The results revealed that dominant anions were HCO 3 -and Cl -and Ca +2 was the dominant cation andoverall water chemistry of the area was CaMgHCO 3 -type. Arsenic concentrations were high, rangedfrom 11 to 828 µg/L that crossed the World Health Organization permissible limits. Likewise, higher SO 4 -2 concentrations ranging from 247 to 1053 mg/L were observed. The health risk index was higher in Sargana site which employed the differences in terms of higher Average Daily Dose,,Hazard Quotient , and Carcinogenic Risk of arsenic. which is unsuitable for drinking purpose. The area seems to be at high risk due to arsenic Downloaded by [University of Otago] at 05:24 06 July 2015 ACCEPTED MANUSCRIPT ACCEPTED MANUSCRIPT 2 pollution and wells have never been tested for arsenic concentrations earlier, therefore necessary measures should be taken to test the wells with respect to arsenic.