02545nas a2200217   4500008004100000022001400041245011400055210006900169260007400238300001000312490000800322520171700330653003002047653001802077653002702095653001402122653001502136100002102151700002402172856013102196       2012                        eng d  a0167-685700aEnhanced tolerance of transgenic grapevines expressing chitinase and beta-1,3-glucanase genes to downy mildew0 aEnhanced tolerance of transgenic grapevines expressing chitinase  aVAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDSbSPRINGERcOCT  a15-280 v1113 a<p>An Agrobacterium-mediated transformation protocol for grapevine cv. Crimson Seedless using sonication and anti-necrotic agents has been optimized, and transgenic lines carrying wheat chitinase and beta-1,3-glucanase genes have exhibited enhanced tolerance to downy mildew incited by Plasmopara viticola. cDNA clones encoding chitinase and beta-1,3-glucanase have been isolated from a cDNA library, constructed from scab-infected Sumai-3 wheat, and introduced into a plant cloning vector to generate the plasmids pCAMBAR.chi.11 and pCAMBAR.638. Embryogenic cultures, established from in vitro-derived leaves, of Crimson Seedless were used as explants for Agrobacterium tumefaciens-mediated transformation studies. Sonication of somatic embryos in a bacterial suspension of A. tumefaciens and incorporation of anti-necrotic agents in the co-cultivation medium significantly enhanced transformation efficiency. Transformation efficiency of embryos with either chitinase or beta-1,3-glucanase gene was highest when embryos were suspended in a bacterial cell suspension at 0.5 OD600 and sonicated for 2 or 3 s at 60 kHz. Transformation efficiency with chitinase was highest on incorporation of 2 or 3 mg l(-1) phenylalanine, 1 or 2 mg l(-1) silver nitrate or 400 mg l(-1) l-cysteine in co-cultivation medium while incorporation of 20 mg l(-1) sodium thiosulphate produced highest transformation efficiency with beta-1,3-glucanase. Confirmed transgenic grapevine lines harboring anti-fungal genes exhibited higher levels of chitinase and beta-1,3-glucanase transcripts as well as enzymatic activities. Moreover, transgenic lines showed enhanced tolerance to P. viticola infection following detached leaf assays.</p>10aAgrobacterium tumefaciens10aAnti-oxidants10aDowny mildew tolerance10aGrapevine10aSonication1 aNookaraju, Akula1 aAgrawal, Dinesh, C.  uhttps://library.ncl.res.in/content/enhanced-tolerance-transgenic-grapevines-expressing-chitinase-and-beta-13-glucanase-genes-0