Cloning And Expression Analysis Of The Resistance Gene RbRdr1 In Rosa Banksiae

Black spot disease of Rosa hybrida is the first disease in open field cultivation of Rosa hybrida,is a worldwide disease,which is common and serious,which is more difficult to prevent and cure,and its pathogenic bacteria is the rose disc ? spore(Marssonina rosae).With the development of the orientation selection,the pathogenic bacteria can easily produce all kinds of physiological small species,which leads to the gradual weakening of the disease resistance.At present,the method of spraying chemical agents can be used to inhibit the production of pathogenic bacteria,but the extensive use of chemical agents not only increases the production cost,but also causes the deterioration of the ecological environment.The further development of molecular biology makes it possible to find the resistance from the plant itself.The Rosa banksiae is the high quality wild resources,is the high anti-black spot disease species.In this study,the entire length of RbRdrl,an anti-black spot gene,was obtained by using TA cloning and RACE technology.And the bioinformatics analysis was performed.Real-time fluorescence quantitative PCR was used to analyze the temporal and spatial expression of the gene in different parts of the tissue and in different periods of the mature leaves infected by black spot bacteria.The main results are as follows:1.A full-length gene was cloned,3462bp.Including a 33bp 5'-UTR,a 3396bp ORF,and a 33bp 3'-UTR.It was named RbRdr1 and GenBank registration number MK584935.2.The subcells of this gene are located in mitochondria and peroxidase bodies,without signal peptide and transmembrane domain,and alpha-helix and random curl are the main secondary structures.Multiple alignment of amino acid homologous sequences showed that RbRdr1 had higher homology with wild rose and rose,among which the homology with wild rose was 86%and rose was 84%.3.Real-time quantitative fluorescence PCR was used to analyze the temporal and spatial expression of RbRdrl in different parts of the tissues and in different periods of the mature leaves infected by black spot bacteria.The results showed that the expression of RbRdrl was significantly different in different tissue sites,with higher expression in young and mature leaves and lower expression in roots,stems and petals.The relative expression of the candidate gene was positively upregulated at different stages of infection by black spot,and was the highest at 6h.This suggests that the candidate gene may be involved in the interaction process of the early host-black spot bacteria.These results lay a foundation for the further study and utilization of anti-black spot gene of Rosa.