Evaluation Of Cold Hardiness In Grape Germplasm Resources And Screening Of Candidate Genes Related To Cold

Grape is an important economic fruit tree in China.However,the climate of main producing areas characterized with drought and cold stresses in winter,which extremely restricts the development of grape industry.In this study,the method of cold hardiness evaluation was performed.GC-TOF/MS techniques were used to analyze metabolites in two varieties with different hardiness and try to find potential substances which could be indicators of cold resistance.The cold resistance of grape germplasm resources and different hybrid populations was evaluated.Meanwhile,QTL was used to identify loci related to cold resistance over three years in genetic map of ‘BH' cross with ‘ES'.The candidate genes associated with grape cold resistance were acquired by combined the genes in QTL with transcriptional analysis of different cold-tolerant grapes.The main results are as follows:1.Optimized method of LTE and used it to evaluate cold resistance of grape germplasm resources.Established an accurate and highly effective evaluation system of the grape dormant bud.The cold resistance of abundant grape germplasm in the field were detected.The results showed that the LTE of wild species was significantly lower than other germplasm including Hybrids,Hybrid between V.vinifera and V.labrusca and V.vinifera.Furthermore,and the cold resistance of the same type varied with cultivars or species.2.GC-TOF/MS was used to determine the changes in the metabolic levels of V.vinifera cv.Muscat of Hamburg and V.amurensis at low temperatures.The results showed that the levels of some sugars,amino acids and organic acids in both two varieties had changed at low temperatures.Twelve substances accumulated only in the V.amurensis,such as isoleucine,?-ketoglutarate,valine and putrescine.The accumulation of these substances may act a role in resistant to cold in V.amurensis.Meanwhile,the analysis of the relationship between the accumulation of metabolites and the transcription levels of encoding genes were analysisd and found some contributing genes to the accumulation of metabolites.3.Cold hardiness of grape dormant buds showed normally distributed in the offspring of the hybrid population,which belong to quantitative trait controlled by multiple genes.Hybrids with strong cold resistance parents showed positive heterosis.Study on the cold resistance between cross and reciprocal cross performed no significant difference,indicating that no cytoplasmic heredity in the cold resistance inheritance.The cold-resistance of the dormant buds had no significant relationship with bud break grade in spring.Significant differences were performed in germination of the different parent combinations in winter in the field.The resultes showed that may be the ability of the parents to resist cold and drought coutribute to the bud break grade in spring.4.The cold hardiness of 'BH' × 'ES' cross population was detected by LTE system in three years.A total of 10 QTL were obtained on parental genetic maps that include 646 genes.Combining QTLs and RNA-Seq analysis,79 candidate genes may involve in cold resistance regulation were identified including WRKY,ERF and GATA.