Qiao Qian, Gao Yun, Liu Qingzhong
Shandong Key Laboratory of Fruit Biotechnology Breeding, Shandong Institute of Pomology, Taian, Shandong, China.
College of Plant Protection, Shandong Agricultural University, Taian, Shandong, China.
Front Plant Sci. 2024 May 21;15:1377899. doi: 10.3389/fpls.2024.1377899. eCollection 2024.
The spines of Chinese red chestnut are red and the depth of their color gradually increases with maturity. To identify the anthocyanin types and synthesis pathways in red chestnut and to identify the key genes regulating the anthocyanin biosynthesis pathway, we obtained and analyzed the transcriptome and anthocyanin metabolism of red chestnut and its control variety with green spines at 3 different periods. GO and KEGG analyses revealed that photosynthesis was more highly enriched in green spines compared with red spines, while processes related to defense and metabolism regulation were more highly enriched in red spines. The analysis showed that the change in spine color promoted photoprotection in red chestnut, especially at the early growth stage, which resulted in the accumulation of differentially expressed genes involved in the defense metabolic pathway. The metabolome results revealed 6 anthocyanins in red spines. Moreover, red spines exhibited high levels of cyanidin, peonidin and pelargonidin and low levels of delphinidin, petunidin and malvidin. Compared with those in the control group, the levels of cyanidin, peonidin, pelargonidin and malvidin in red spines were significantly increased, indicating that the cyanidin and pelargonidin pathways were enriched in the synthesis of anthocyanins in red spines, whereas the delphinidin pathways were inhibited and mostly transformed into malvidin. During the process of flower pigment synthesis, the expression of the , , , , , and genes clearly increased, that of decreased obviously, and that of , and both increased and decreased. Notably, the findings revealed that the synthesized anthocyanin can be converted into anthocyanidin or epicatechin. In red spines, the upregulation of gene expression increases the corresponding anthocyanidin content, and the upregulation of the gene also promotes the conversion of anthocyanin to epicatechin. The transcription factors involved in color formation included 4 .
中国红栗的刺呈红色，且颜色深度随成熟度逐渐增加。为了鉴定红栗中花青素的类型和合成途径，并确定调控花青素生物合成途径的关键基因，我们获取并分析了红栗及其绿色刺对照品种在3个不同时期的转录组和花青素代谢情况。基因本体（GO）和京都基因与基因组百科全书（KEGG）分析表明，与红刺相比，绿色刺中光合作用的富集程度更高，而与防御和代谢调控相关的过程在红刺中的富集程度更高。分析表明，刺颜色的变化促进了红栗的光保护作用，尤其是在生长早期，这导致了参与防御代谢途径的差异表达基因的积累。代谢组学结果显示红刺中有6种花青素。此外，红刺中矢车菊素、芍药素和天竺葵素含量较高，而飞燕草素、矮牵牛素和锦葵色素含量较低。与对照组相比，红刺中矢车菊素、芍药素、天竺葵素和锦葵色素的含量显著增加，表明矢车菊素和天竺葵素途径在红刺花青素合成中富集，而飞燕草素途径受到抑制且大多转化为锦葵色素。在花色素合成过程中， 、 、 、 、 、 和 基因的表达明显增加， 基因的表达明显下降， 、 和 基因的表达既有增加也有下降。值得注意的是，研究结果表明合成的花青素可转化为花青素或表儿茶素。在红刺中， 基因表达的上调增加了相应的花青素含量， 基因的上调也促进了花青素向表儿茶素的转化。参与颜色形成的转录因子包括4个 。
