PbGA2ox8 induces vascular-related anthocyanin accumulation and contributes to red stripe formation on pear fruit  

作　　者：Rui Zhai Zhigang Wang Chengquan Yang Kui Lin-Wang Richard Espley Jianlong Liu Xieyu Li Zhongying Wu Pengmin Li Qingmei Guan Fengwang Ma Lingfei Xu 

机构地区：[1]College of Horticulture,Northwest A&F University,Taicheng Road No.3,Yangling,Shaanxi Province,China [2]The New Zealand Institute for Plant&Food Research,Ltd.,(Plant and Food Research),Mt.Albert Research Centre,Private Bag,92169 Auckland,New Zealand [3]Horticultural Research Institute,Henan Academy of Agricultural Sciences,Huayuan Road No.116,Zhengzhou,Henan Province,China [4]State Key Laboratory of Crop Stress Biology for Arid Areas,Northwest A&F University,Taicheng Road No.3,Yangling,Shaanxi Province,China

出　　处：《Horticulture Research》2019年第1期18-30,共13页园艺研究（英文）

基　　金：supported by the National Natural Science Foundation of China(31572086,31171925,and 31401845);the China Agriculture Research System(CARS 28-45).

摘　　要：Fruit with stripes,which are generally longitudinal,can occur naturally,but the bioprocesses underlying this phenomenon are unclear.Previously,we observed an atypical anthocyanin distribution that caused red-striped fruit on the spontaneous pear bud sport“Red Zaosu”(Pyrus bretschneideri Rehd.).In this study,comparative transcriptome analysis of the sport and wild-type“Zaosu”revealed that this atypical anthocyanin accumulation was tightly correlated with abnormal overexpression of the gene-encoding gibberellin(GA)2-beta-dioxygenase 8,PbGA2ox8.Consistently,decreased methylation was also observed in the promoter region of PbGA2ox8 from“Red Zaosu”compared with“Zaosu”.Moreover,the GA levels in“Red Zaosu”seedlings were lower than those in“Zaosu”seedlings,and the application of exogenous GA4 reduced abnormal anthocyanin accumulation in“Red Zaosu”.Transient overexpression of PbGA2ox8 reduced the GA4 level and caused anthocyanin accumulation in pear fruit skin.Moreover,the presence of red stripes indicated anthocyanin accumulation in the hypanthial epidermal layer near vascular branches(VBs)in“Red Zaosu”.Transient overexpression of PbGA2ox8 resulting from vacuum infiltration induced anthocyanin accumulation preferentially in calcium-enriched areas near the vascular bundles in pear leaves.We propose a fruit-striping mechanism,in which the abnormal overexpression of PbGA2ox8 in“Red Zaosu”induces the formation of a longitudinal array of anthocyanin stripes near vascular bundles in fruit.

关 键 词：ANTHOCYANIN FRUIT ABNORMAL 

分 类 号：S66[农业科学—果树学]