Dihydro Jasmonate (the Pdj) The Impact Of Two Plant Rna Viruses

Plan hOrmones and their synthesized analogies have been widely used as plangroWth regulators, for induced stressAolerance, increasing yield and improving qualityand other purpose in crop production and horticulture. Bllt their effect on virusinfection of croP plans was seldom stUdied and documented. n-Propyl dihydro-jasmonate (PDJ) is an artificially synthesized chemical smicedly resemblingjasmonic acid, Which was found to be a new and effective plan hormone analogy Thepresent research is to qUanitatively determine the influence of PDJ on the loadinglevel of tWo plant RNA viruses- cucumber mosaic virus (CMV) and tobacco mosaicvirus (TMV), on their model plants- Nicandra physalodes and Nicotiana tObaccumrespectively, by treatment of differeflt concentrations. The relative contents of CMVsatellite RNA were comPared with that of genomic RNA by repeated KNAhybridization with the sarne sample, For making better understanding of the way ofPDJ effect on the interaction of satellite RNA and CMV as helper virus.The influence of PDJ trcatment cucumber mosaic virus: A series of PDJconcentration solution ranging from 50ppm to 0.00lPPm was prepared and sprayedonto plants, Which were inoculated by a CMV staln-YI tWO days before. A '2P labeledcDNA probe containing a subgenomi c -axA-pro moter s equenc e o f RNA3 was usedfor dot ANA hybridization. The RNA-loading of CMV of each treatment wasquantitatively tested frOm each 0.2 grams of fresh leaf tissue at 7d, l4d, 21d, 28d. 42dand 58d respectively Strong concefltTation -effect and time~effect were fOUnd on theinduence of PDJ to CMV loading. At the early stage, PDJ obviously stimulates thereplication and accumulation of CMV RNA. But after 14 days of the treatment, mostof trearments of PDJ showed a concentration suppression of CMV in compare withthe control. There were also significan differences among different PDJ concentrationtreatments. Using ChenOPodium amaranticolor as the local-Iesion teSt host, therelative ithectivity. presented by the local lesion SPOts obtained from the treated planttissue of Mcandra physalodes, 0.3 gram each, was qUanitatively determined by semi-leaf inoculation technques of leaf tissue from each treatment. The inoculation testgave similar intendance as the RNA hybridization.The influence of PDJ treatment on satellite RNA of cucumbcr mosaic virus:CucUmber mosaic virus sate1lite RNAs (sat-RNA) are a grouP of small RNAmolecules, and they dePend on the helper virus for their replication, spreading withinplant tissues and en-caPsizing. A "P Iabeled cDNA probe coniaining the full sequenceof CMV YI satellite cDNA, Which was 396 bp long was used fOr dot RNAhybridization and fOr quanitative determination of the relative amount for saelliteRNA. The ratios of CMV-YI satellite RNA to itS gnomic ANA, from the sarne amountof plan tissue of Ncandra phySalodes, were determined at 7d, 28d and 42d aftertreatment by different concentfation of PDJ. Firstly, an obvious influence of PDJtreatment on the satellite RNA-loading was observed. The influence of PDJ treaAnellthad strong concentration-effect and time-effect. Second, it was different of thedisciplinarian of PDJ influencing on the satellite RNA and on CMV-YI gnomic RNA.At both 7d and 28d. PDJ treatment relatively suPPressed the accumulation of satelliteANA, but enhancing the accumulation of CMV genomic RNA. At 42 d of PDJtreatInent, the accumulation of satellite was enhanced, but that of CMV genomic ANAwas suppressed. Thus the influence of PDJ on the satellite RNA and genomic RNA ofCMV are of different characters.The innuence of PDJ treatment on tobacco mosaic virus: The saxne tecboques, dotRNA hybridization and semi-leaf inoculation tecboques were used for detection oftobacco mosaic virus (TMV) loading on tobacco plans, with the treatInent of PDJconcentration from 0.00lppm to l0ppm. The PDJ treatment was aPplied onto tobaccoleaves 7d after inoculation. The resu1ts indicat...