natural-products-in-plant-pest-management

156 H.N. Verma and V.K. BaranwalChen et al., 1991; Picard et al., 2005). PAP also shows antiviral activity againstseveral animal viruses. It is toxic to cells infected with poliovirus (Usseryet al., 1977) and influenza virus (Tomlinson et al., 1974). It inhibits multiplicationof herpes simplex virus type 1 (Arnon and Irvin, 1980) and humanimmunodeficiency virus (HIV; Zarling et al., 1990). P. americana is now knownto contain three proteins (PAP I, II and III) with similar biological properties.A new insight into the antiviral mechanism of PAP is that PAP depurinationof Brome mosaic virus RNA impedes both RNA replication and subgenomicRNA transcription (Picard et al., 2005).Rajmohan et al. (1999) reported that PAP isoforms PAP-I, PAP-II andPAP-III depurinate RNA of HIV-I. A non-toxic PAP mutant inhibiting pathogeninfection via a novel SA-independent pathway was reported byZoubenko et al. (2000). PAP inhibits translation by depurinating the conservedsarcin/ricin loop of the large ribosomal RNA. Depurinating ribosomesare unable to bind elongation factor 2, and, thus, the translocation stepof the elongation cycle is inhibited. Ribosomal conformation is required fordepurination that leads to subsequent translation inhibition (Mansouri et al.,2006).Carnation antiviral proteins (Dianthins)Sap from carnation leaves shows virus inhibitory activity (Van Kammenet al., 1961; Ragetli et al., 1962). Dianthin 30 and 32 were isolated from theleaves of Dianthus caryophyllus (Ragetli et al., 1962). Local lesion productionby TMV on N. glutinosa was inhibited by 100% when the inhibitor was coinoculatedwith the virus (Stevens et al., 1981). The molecular weights asdetermined by SDS–PAGE are 29.5 and 31.7 kDa, respectively (Stirpe et al.,1981). Immunoelectrophoresis revealed that dianthin 32 is distributed in thegrowing shoots and in the young and old leaves of D. caryophyllus and dianthin30 is distributed throughout the plant (Reisbig and Bruland, 1983). Thetwo are glycoproteins containing mannose and show a weak cross reaction.The nucleotide sequence of cDNA encoding dianthin 30 has been determined(Legname et al., 1991). The carnation proteins are also inducers of systemicresistance (Plobner and Leiser, 1990). Cho et al. (2000) performed isolationand characterization of cDNA encoding ribosome inactivating protein fromDianthus sinensis L.Mirabilis antiviral protein (MAP)The roots, leaves and stem of Mirabilis jalapa show high inhibitory activityagainst plant viruses. The Mirabilis jalapa leaf extract, when used as a foliarspray 24 h prior to virus inoculation, suppressed disease symptoms on a fewsystemic hosts (tomato/tomato yellow mottle virus; Cucumis melo var.momordica/CMV; Cucumis sativa/cucumber green mottle mosaic virus;tomato/tomato yellow mosaic virus; urd/yellow mosaic of urd) (Verma and