College of Biotechnology, Jiangsu University of Science and Technology, Zhenjiang 212018, China.
Sericultural Research Institute, Chinese Academy of Agricultural Sciences, Zhenjiang 212018, China.
Molecules. 2022 May 23;27(10):3341. doi: 10.3390/molecules27103341.
Mulberry ( spp., Moraceae) is an important economic crop plant and is rich in flavonoids and anthocyanidins in ripe fruits. Anthocyanins are glycosides of anthocyanidins. Flavanone 3-hydroxylase (F3H) catalyzes the conversion of naringenin into dihydroflavonols and is responsible for the biosynthesis of flavonols and anthocyanidins. In this study, was cloned and characterized from var. Conserved motif analysis based on alignment and phylogenetic analysis indicated that belonged to 2-oxoglutarate-dependent dioxygenase and clustered with F3Hs from other plants. was located in both nucleus and cytosol. was expressed in stems, leaves, stigmas and ovaries, except buds. expression levels showed a positive and close relationship with anthocyanin content during the anthocyanin-rich fruit ripening process, while it showed a negative correlation with anthocyanin content in , whose fruits are white and would not experience anthocyanin accumulation during fruit ripening. Significantly different expression levels were also found in different mulberry varieties that have quite different anthocyanin contents in ripe fruits. Overexpression in tobacco showed unexpected results, including decreased anthocyanin content. Down-regulation of expression levels resulted in co-expression of the genes involved in anthocyanin biosynthesis and a significant decrease in anthocyanin content, but the change in total flavonoid content was subtle. Our results indicated that F3H may play quite different roles in different varieties that have quite different fruit colors. In addition, possible complex regulation of flavonoid biosynthesis should be further explored in some of the featured plant species.
桑树（ spp.，桑科）是一种重要的经济作物，其成熟果实富含类黄酮和花色苷。花色苷是花色苷元的糖苷。黄烷酮 3-羟化酶（F3H）催化橙皮素转化为二氢黄酮醇，负责类黄酮和花色苷的生物合成。本研究从 var. 中克隆并鉴定了 。基于比对和系统发育分析的保守基序分析表明， 属于 2-氧戊二酸依赖性双加氧酶，与其他植物的 F3Hs 聚类。 位于细胞核和细胞质中。 在茎、叶、柱头和子房中表达，除芽外。在富含花色苷的果实成熟过程中， 表达水平与花色苷含量呈正相关且密切相关，而在 中，花色苷含量呈负相关，其果实为白色，在果实成熟过程中不会积累花色苷。在不同花色苷含量差异较大的不同桑品种中，也发现了 表达水平的显著差异。 在烟草中过表达 会产生意想不到的结果，包括花色苷含量降低。下调 表达水平导致参与花色苷生物合成的基因共表达，花色苷含量显著降低，但总类黄酮含量变化较小。研究结果表明，F3H 在花色苷含量差异较大的不同品种中可能发挥不同的作用。此外，在一些特色植物物种中，应进一步探索黄酮类生物合成的可能复杂调控。
