Effect Of Temperature And Different Antiviral Medicines On Areca Palm Velarivirus1(APV1) And Symptoms Of Yellow Leaf Disease (YLD)

1.Areca catechu L.,also called as the betel palm,has been threatened by yellow leaf disease(YLD),worldwide.In previous work,YLD was proved to be associated with areca palm velarivirus 1(APV1).It was observed previously that the seasonal oscillation occurred in YLD symptoms,having severe chlorosis in Winter than Summer,and was connected with physiological yellowing.In the current research work,the mechanism underlying was explored.We investigate that in the field the symptoms severance is connected with APV1 concentration,contingent on ELISA and qRT-PCR analysis,but to know about the temperature role in disease incidence the same assay was also developed inside the lab in control conditions. Our findings observed severest symptoms at low(16/22 ℃),severer symptoms at room(24/26 ℃),while temperate symptoms at high(27/34 ℃),(night/day temperature.The APV1 titers found expressively high at cold conditions than hot and room conditions via;ELISA and q RT-PCR.The order of affectivity of temperature on YLD is severest> severer> moderate at low> room> high temperatures,respectively.These data suggest that temperature is a key environmental factor that effects APV1 and YLD symptoms.High temperature might inhibit the replication of APV1.2.In order to develop the prevention methods for YLD incidence,the screening of some antiviral drugs inhibiting APV1 accumulation was carried out.For that purpose,the Melatonin,Ningnanmycin,Ribavirin,Dufulin,and Moroxydine were applied on YLD infected seedlings.The YLD symptoms and APV1 titer accumulation were investigated after treatment of foliar applications.The results show that NNM,ME,NNM+ME,Ribavirin,and Moroxydine,have clear effect on YLD symptoms and APV1 titer eradication,as compared to control(disease plant without any treatment).The symptoms become milder and the APV1 accumulation were also declined as compared to untreated diseased plants,while the effect of Dufulin on YLD symptoms and APV1 accumulation were not so significant.The chlorophyll florescence intensity was also analyzed in the above mentioned drugs treatments.The level of Fv/Fm,e.g.Maximum quantum of PSII, is elevated by NNM,ME,ME+NNM,and Moroxydine treatments.3.Furthermore,differentially expressed novel miRNAs were obtained through sRNA sequencing of Wanning and Baoting YLD samples as compared to healthy betel palms.The majority of the YLD-related miRNAs were expressed significantly high at low temperature than high and room temperatures.These miRNAs were upregulated in NNM,ME,ME+NNM,Ribavirin and Moroxydine treatments,while unchanged in Dufulin treatment.Three novel miRNAs i.e. Novel＿31,Novel＿32,and Novel＿40 were selected for prediction of target genes by in-silico via;various bioinformatics tools.The expression levels of miRNAs and their target genes were also corroborated through q RT-PCR.The functional characterization of these target genes needs to be investigated in the future.In conclusion,this is the initial report about different temperature,and antiviral drugs effects on YLD incidence,and YLD-relative miRNAs expression,that will lay a foundation for characterization of the YLD pathogenesis and fill important gaps in YLD control management strategies.