Zorenc Zala, Veberic Robert, Slatnar Ana, Koron Darinka, Miosic Silvija, Chen Ming-Hui, Haselmair-Gosch Christian, Halbwirth Heidi, Mikulic-Petkovsek Maja
Department of Agronomy, Chair for Fruit, Wine and Vegetable Growing, Biotechnical Faculty, University of Ljubljana, Ljubljana, Slovenia.
Department of Fruit Growing, Viticulture and Oenology, Agricultural Institute of Slovenia, Ljubljana, Slovenia.
PLoS One. 2017 Dec 22;12(12):e0190246. doi: 10.1371/journal.pone.0190246. eCollection 2017.
Relative expressions of structural genes and a number of transcription factors of the anthocyanin pathway relevant in Vaccinium species, and related key enzyme activities were compared with the composition and content of metabolites in skins of ripe fruits of wild albino and blue bilberry (Vaccinium myrtillus) found in Slovenia. Compared to the common blue type, the albino variant had a 151-fold lower total anthocyanin and a 7-fold lower total phenolic content in their berry skin, which correlated with lower gene expression of flavonoid 3-O-glycosyltransferase (FGT; 33-fold), flavanone 3-hydroxylase (FHT; 18-fold), anthocyanidin synthase (ANS; 11-fold), chalcone synthase (CHS, 7.6-fold) and MYBPA1 transcription factor (22-fold). The expression of chalcone isomerase (CHI), dihydroflavonol 4-reductase (DFR), leucoanthocyanidin reductase (LAR), anthocyanidin reductase (ANR) and MYBC2 transcription factor was reduced only by a factor of 1.5-2 in the albino berry skins, while MYBR3 and flavonoid 3',5'-hydroxylase (F3'5'H) were increased to a similar extent. Expression of the SQUAMOSA class transcription factor TDR4, in contrast, was independent of the color type and does therefore not seem to be correlated with anthocyanin formation in this variant. At the level of enzymes, significantly lower FHT and DFR activities, but not of phenylalanine ammonia-lyase (PAL) and CHS/CHI, were observed in the fruit skins of albino bilberries. A strong increase in relative hydroxycinnamic acid derivative concentrations indicates the presence of an additional bottleneck in the general phenylpropanoid pathway at a so far unknown step between PAL and CHS.
将斯洛文尼亚发现的野生白化蓝莓和蓝色越橘(笃斯越橘)成熟果实果皮中的代谢物组成和含量,与越橘属植物中花青素途径的结构基因和一些转录因子的相对表达以及相关关键酶活性进行了比较。与常见的蓝色类型相比,白化变种的浆果果皮中总花青素含量低151倍,总酚含量低7倍,这与类黄酮3 - O - 糖基转移酶(FGT;低33倍)、黄烷酮3 - 羟化酶(FHT;低18倍)、花青素合酶(ANS;低11倍)、查尔酮合酶(CHS,低7.6倍)和MYBPA1转录因子(低22倍)的基因表达降低相关。白化浆果果皮中查尔酮异构酶(CHI)、二氢黄酮醇4 - 还原酶(DFR)、无色花青素还原酶(LAR)、花青素还原酶(ANR)和MYBC2转录因子的表达仅降低了1.5 - 2倍,而MYBR3和类黄酮3',5'-羟化酶(F3'5'H)则有类似程度的增加。相比之下,SQUAMOSA类转录因子TDR4的表达与颜色类型无关,因此似乎与该变种中的花青素形成无关。在酶水平上,白化越橘的果实果皮中观察到FHT和DFR活性显著降低,但苯丙氨酸解氨酶(PAL)和CHS/CHI的活性没有降低。相对羟基肉桂酸衍生物浓度的大幅增加表明,在苯丙烷类通用途径中,在PAL和CHS之间迄今未知的步骤存在额外的瓶颈。