Identification Of Phenolic Compounds In Pear Germplasm Resources And Correlation Analysis Related To Resistant To Valsa Canker

The phenolic compounds in the one-year-old branch of 46 accessions in Pyrus germplasm resourses had been studied qualitatively and quantitatively by method of HPLC and LC-MS/MS. Based on this, correlation analysis between the degree of branch incidence of 46 accessions in Pyrus germplasm resourses and the content of each phenolic compounds component had been analysed by using SPSS software. Meanwhile, analysis was carried out about the change of the content of the related phenolic components with and without Valsa canker pathogen inoculation.The results were as follows:(1)Through optimization, the optimum conditions for the liquid phase separation had been determined:the mobile phases which consisted of methanol plus 0.1% formic acid and water plus 0.1% formic acid were applied for elution gradients; separations were carried out using a reverse phase column maintained at 30℃, eluted at 0.4 mL/min with a 90 min gradient, registered the chromatograms at 280 nm.The optimum conditions for UPLC-MS/MS had been determined:MS analysis was carried out using electrospray ionization (ESI) interface in negative ionization mode. Detection was carried out within a mass range of 100-2000 m/z. Drying gas flow was 6 L/min, drying gas temperature was 350℃, nebulizer gas pressure was 45 psi, capillary voltage was 3500 V.(2)Through the identification, a total of 44 kinds of phenolic compounds were found, the largest phenolic compound was arbutin, the content of which was up to 5300mg/L in ’Chougaizi’which is belonging to P. ussuriensis Maxim. Chlorogenic acid was second, the content in ’Banjinsu’ which is belonging to P. bretschneideri Rehd. was up to 640mg/L. In addition, catechin, epicatechin etc. also had a comparative high level of the content. Correlation analysis by using SPSS software found that protocatechuic acid, catechol and catechin in P. pyrifolia Nakai were associated with anti-Valsa canker and so did arbutin, gallic acid in P. bretschneideri Rehd., coumaroylquinic acid, quercetin glycoside and naringin in P. ussuriensis Maxim., arbutin, vanillic acid glucoside and chlorogenic acid in P. sinkiangensis T.T.Yu, gallic acid,ρ-coumaric acid and feruloylquinic acid in P. communis L. as well.(3) Inoculate Valsa canker pathogen in resistant varieties, including P.bretschneideri Rehd.Chili, P. bretschneideri Rehd.Qiubai, P. calleryana Decne Douli and P.betulaefolia Bge Duli. The results were as follows:The content of arbutin, catechin, chlorogenic acid, epicatechin, quercetin glycoside and phlorizin dihydrate changed significantly in canker-resistant germplasm P. bretschneideri Rehd.Qiubai after inoculated with Valsa mali var. pyri; After inoculation 48h, the content of arbutin, catechin, and epicatechin significantly increased in canker-susceptivegermplasm P. bretschneideri Rehd.Chili. After inoculation 48 h, the content of arbutin, chlorogenic acid and cinnamic acid decreased significantly in P. calleryana Decne Douli. After inoculated against Valsa canker pathogen, the content of arbutin, sorhamnetin glucoside, catechol, catechin, chlorogenic acid, epicatechin, quercetin glycoside, isorhamnetin-3-o-rutinoside, phlorizin dihydrate and cinnamic acid in P. betulaefolia Bge Duli were significantly increased, but did not change significantly in the vaccination of 12 h and 48 h.