| Rice black streaked dwarf disease and rice stripe disease are viral diseases caused by RBSDV(Rice black streaked dwarf virus)and RSV(Rice stripe virus),respectively.Both RBSDV and RSV can be transmitted by Laodelphax striatellus.These two diseases are prevalent in a wide range of areas.When the disease occurs,it causes a large yield reduction and even the death of rice seedlings,which causes great harm to rice production.Studying disease resistance mechanism and breeding resistant varieties are the most economical and effective way to control disease.In this study,the role of three genes encoding cyclic nucleotide gated ion channels(CNGCs),OsCNGC14,OsCNGC15 and OsCNGC16,in the regulation of RBSDV resistance in rice was investigated.In addition,genome-wide association analysis(GWAS)was used to identify genetic loci associated with RSV resistance in natural populations of Arabidopsis thaliana and the function of candidate genes was investigated.The main results of this thesis are as follows:1.Calcium signal is the early signal in plant defense response,and CNGC is known to play an important role in plant bacterial disease resistance.However,it is still unknown whether CNGC is involved in antiviral regulation in plants.In order to answer this question,we analyzed the functions of three rice CNGC family genes OsCNGC14,OsCNGC15 and OsCNGC16 in disease resistance to rice black-streamed dwarf virus.Virus resistance analysis showed that mutations of each of OsCNGC14,OsCNGC15 and OsCNGC16 significantly reduced resistance to RBSDV.In addition,mutations of each of OsCNGC14,OsCNGC15 and OsCNGC16 significantly reduced the sensitivity to jasmonic acid(JA)and inhibited the expression of JA responsive genes induced by RBSDV.In conclusion,this study shows that OsCNGC genes positively regulate rice resistance to RBSDV,and it may do so through the JA signaling pathway.2.Discover RSV resistance genes and studying their regulatory functions are important for understanding the molecular mechanisms of RSV resistance and breeding RSV resistant rice varieties.In this study,89 ecotype of Arabidopsis thaliana were used for Genome-wide association analysis(GWAS)of RSV resistance.Two loci significantly associated with RSV resistance were identified on chromosome 5,and five candidate genes were screened in these two loci: At PNTP,At CYP81K1,At CYP81K2,At5G10605 and At5G10620.Mutants of the above candidate genes were analyzed for their RSV resistance phenotypes.The results indicated that At PNTP and At CYP81K1 may negatively regulate Arabidopsis resistance to RSV. |
