Gene Expression Profiles Of Host Interactions Involving Rosa Multiflora And Podosphera Pannosa

Rosa chinensis is one of the four largest cut-flowers in the world. And Powdery Mildew is one of the most serious diseases in rose production especially in greenhouses, Which reduce the income of farmers. Improving resistance to Powdery Mildew through breeding technology is a environment-friendly way to decrease the production cost. researchers suggest using excellent traits/genes in wild Rosa to solve the breeding challenge. We first do strain identification and resistance identification of Rosa multiflora, then study on Gene expression profiles of Rosa multiflora under the treatment of Podosphera pannosa, and analysis the expressing patterns of8genes selected from expression profiling data with the relative quantitative PCR verifieation analysis. The main results are as follows:(1) The regeneration media component of Rosa multiflora "1","4","13" is MS+6-BA1mg/L+NAA0.01mg/L+30g/L sucrose+7.5g/L agar. And the Rosa multiflora "1" need a strengthening stage after the regenerating stage, the strengthening media component is MS+6-BA0.1mg/L+NAA0.01mg/L+30g/L sucrose+7.5g/L agar.(2) To investigate the Powdery mildew of Rosa multiflora, the characteristics of morphological, and molecular identification were tested. The results show the Powdery mildew of Rosa multiflora is Podosphera pannosa.(3) To investigate the resistance of Rosa multiflora to Podosphera pannosa, three methods (measuring the natural infection rate in the field,the spore-suspension inoculation to cutting plants method and micro-observation method)were used. The comprehensive conclution is that Rosa multiflora "13" is high resistant, Rosa multiflora "1" is moderately sensitive, Rosa multiflora "1" is highly sensitive.(4) After feeding by Podosphera pannosa for24h, mRNA levels changed for1900genes in the resistant plants and1614genes in the sensitive plants; and1426genes up-regulated,240genes down-regulated only in the resistant plants. After feeding by Podosphera pannosa for96h, mRNA levels changed for1839genes in the resistant plants and2360genes in the sensitive plants; mRNA levels of413genes enhanced,and392genes decreased only in the resistant plants.(5) GO functions significant enrichment analysis indicated that differentially expressed genes in both the resistant and sensitive plants involved in a lot of functions. Comparing the functions of differentially expressed genes in the resistant and sensitive plants, It is indicated that the functions only in resistant plants are glucan metabolic process, guard cell development, cellulose metabolic process, callose deposition in cell wall, photosynthesis, light harvesting in photosystem II, abscisic acid biosynthetic process, secondary cell wall biogenesis, hydrolase activity, microtubule,1,3-beta-D-glucan synthase complex, et al.(6) In order to get relative expression datas of8selected genes,we take GADPH as a reference gene to apply quantitative real-time PCR. The results showed the expressing patterns of7genes were different in the resistant and sensitive plants, which may take important roles in disease resistance.