Research On The Sporulation Characteristics And Mycoviruses In Brown Spot Disease Of Zizania Latifolia

Zizania latifolia is a perennial herbaceous plant of Gramineae.Due to the large-scale planting of Zizania latifolia,the brown spot of Zizania latifolia has appeared in many production areas Brown spot disease is a fungal disease caused by Bipolaris oryzae.Zizania latifolia brown spot disease mainly damaged the leaves of Zizania latifolia,resulting in premature senescence and death of the plant,and a significant decline in yield and quality,resulting in the reduction of yield and quality of Zizania latifolia.At present,the main control methods of Zizania latifolia brown spot are agricultural control and chemical control.Considering the problems of environmental pollution and food safety,biological control methods have been paid more and more attention.The conidia of Zizania latifolia brown spot were not easy to produce conidia under artificial culture conditions,which hindered the identification and detoxification of the pathogen.The biological characteristics and sporulation conditions of the fungus were studied in order to lay a theoretical foundation for the identification of Zizania latifolia brown spot and the acquisition of virus-free strain.Fungal viruses are a class of viruses that can infect,replicate and reproduce in filamentous fungi,yeasts and oomycetes,and widely exist in the main groups of fungi and oomycetes.Fungal viruses mainly include dsRNA virus,+ss RNA virus,-ss RNA virus,ss DNA virus,and RNA-RT virus.The research on the fungal diseases contained in the Bipolaris oryzae aims to find the fungal viruses associated with the attenuated virulence,which can be used in the biological control of Zizania latifolia brown spot.In nature,the rate of vertical transmission depending on conidia is very low.Some fungal viruses can be removed from the host by conidia.However,the in vitro culture of Inapira spores does not produce or produces a very small amount of conidia.In this paper,the effects of medium,temperature,light and mycelium damage on the growth rate,colony morphology and conidia production of Zizania latifolia were studied.The optimum sporulation conditions of Zizania latifolia were madeclear,that is agar medium of water bamboo culm juice,light dark alternation at25?,12 h light/12 h dark alternately,mycelium damage and culture for 10 days.The dsRNA detection of 43 strains of Zizania latifolia leaf spot showed that46.5% of the strains contained dsRNA,and the existence of dsRNA was universal in Zizania latifolia.In addition,total RNA of all strains was extracted and sequenced by the high-throughput sequencing technology,and 28 kinds of viruses were detected.It contains dsRNA viruses,+ss RNA viruses,-ss RNA viruses,unclassified RNA viruses and some unclassified viruses.RT-PCR results showed that each strain contained at least two kinds of viruses.It can be seen that the fungal viruses carried by Zizania latifolia have a certain diversity,and the weak strains carrying the fungal viruses have potential biological control effect.Therefore,the full-length cloning and phylogenetic analysis of Bipolaris oryzae partitivirus 1(Bo PV1)were carried out.Firstly,the partial c DNA sequences of Bo PV1 were obtained by high-throughput sequencing,and then the full-length c DNA sequences of S1-dsRNA and S2-dsRNA fragments of Bo PV1 genome were obtained by race method.The dsRNA1 fragment contains 2322 nucleotides,including an ORF,encoding the Rd Rp of the virus.dsRNA2 c DNA contains 2328 nucleotides and an ORF,which encodes the CP protein of the virus.Multiple alignment and cluster analysis based on Rd Rp domain and CP protein sequence showed that Bo PV1 belonged to Betapartitivirus.