Response of Anthocyanin Accumulation in Pepper (Capsicum annuum) Fruit to Light Days

Abstract

Light is the key factor affecting the synthesis of anthocyanins in pepper. In this study, pepper fruit under different light days was used as experimental material to explore the synthesis of anthocyanins in purple pepper. A total of 38 flavonoid metabolites were identified in the purple pepper germplasm HNUCA21 by liquid chromatography–tandem mass spectrometry (LC-MS/MS), of which 30 belong to anthocyanins. The detected anthocyanin with the highest content was Delphinidin-3-O-glucoside (17.13 µg/g), which reached the maximum after 168 h of light treatment. Through weighted gene co-expression network analysis (WGCNA), the brown module was identified to be related to the early synthesis of anthocyanins. This module contains many structural genes related to flavonoid synthesis, including chalcone synthase (CHS 107871256, 107864266), chalcone isomerase (CHI 107871144, 107852750), dihydroflavonol 4-reductase (DFR 107860031), flavonoid 3′ 5′-hydroxylase (F3’5’H 107848667), flavonoid 3′-monooxygenase (F3M 107862334), leucoanthocyanidin dioxygenase (LDOX 107866341), and trans-cinnamate 4-monooxygenase (TCM 107875406, 107875407). The module also contained some genes related to anthocyanin transport function, such as glutathione S-transferase (GST 107861273), anthocyanidin 3-O-glucosyltransferase (UDPGT 107861697, 107843659), and MATE (107863234, 107844661), as well as some transcription factors, such as EGL1 (107865400), basic helix-loop-helix 104 (bHLH104 107864591), and WRKY44 (107843538, 107843524). The co-expression regulatory network indicated the involvement of CHS, DFR, CHI, and EGL1, as well as two MATE and two WRKY44 genes in anthocyanin synthesis. The identified genes involved in early, middle, and late light response provided a reference for the further analysis of the regulatory mechanism of anthocyanin biosynthesis in pepper.

A Metabolome Analysis and the Immunity of Phlomis purpurea against Phytophthora cinnamomi

“…In P. purpurea , the flavonoids content is high in the roots throughout the challenge time and decreases in the leaves from 48 hpc, while increasing in the roots. Within the cell, chalcone isomerase is involved in the synthesis of flavonoids [ 86 ]. In Phlomis purpurea challenged with Phytophthora cinnamomi , the high up-regulation of chalcone isomerase after a challenge [ 25 ] accounts for the increased production of this secondary metabolite.…”

Genetic Regulation, Environmental Cues, and Extraction Methods for Higher Yield of Secondary Metabolites in Capsicum

“…67 Several differentially expressed genes of the flavonoid pathway, such as F3H, CHS2, CYP98A2-like, TCM, TCM-like, SHT, F3′5′H, LDOX, CCoAOMT, F3′M, CHS1B, and AT-like, and enriched transcription factors, for instance, MYB4-like, MYB113-like, MYB308-like, bHLH104, WRKY44, and EGL1, were revealed for light-regulated anthocyanin biosynthesis in purple C. annuum "HNUCA21". 34 Apart from DFR, CHI, and ANS, biosynthetic enzymes such as PAL, C4H, and UFGT were also highly expressed in anthocyanin-rich purple pepper fruits. 68 TF gene family B-Box (CaBBX) genes were coexpressed with anthocyanin pathway genes and speculated for their role in anthocyanin accumulation in C. annuum.…”

“…Representative biosynthetic pathways of major secondary metabolites in Capsicum and their possible transcriptional controls redrawn based on previous reports. − Capsaicinoids are synthesized by the enzymatic condensation of vanillylamine from the phenylpropanoid pathway and a branched-chain fatty acid in the presence of capsaicin synthase (CS/Pun1), whereas nonpungent capsinoids are formed by the condensation of vanillyl alcohol in place of vanillylamine. The flavonoid biosynthetic pathway also emerges from the phenylpropanoid pathway but later directed by several enzymes such as dihydroflavonol 4-reductase (DFR) and anthocyanidin synthase (ANS) forms anthocyanidins as precursors for anthocyanins.…”

“…The metabolome and transcriptome data of the purple pepper variety showed high correlation between the number of flavonoids and gene expression of flavonoid pathway and regulatory genes . Several differentially expressed genes of the flavonoid pathway, such as F3H , CHS2 , CYP98A2-like , TCM , TCM-like , SHT , F3′5′H , LDOX , CCoAOMT , F3′M , CHS1B , and AT-like , and enriched transcription factors, for instance, MYB4-like , MYB113-like , MYB308-like , bHLH104 , WRKY44 , and EGL1 , were revealed for light-regulated anthocyanin biosynthesis in purple C. annuum “HNUCA21” . Apart from DFR , CHI , and ANS , biosynthetic enzymes such as PAL , C4H , and UFGT were also highly expressed in anthocyanin-rich purple pepper fruits .…”

Genetic Analyses of Seed Longevity in Capsicum annuum L. in Cold Storage Conditions

“…Table S6: Total number of germination assays performed after various years of storage. References [ 70 , 71 , 72 , 73 , 74 , 75 , 76 , 77 , 78 , 79 , 80 , 81 , 82 , 83 , 84 , 85 , 86 , 87 , 88 , 89 , 90 , 91 , 92 , 93 , 94 , 95 , 96 , 97 , 98 , 99 , 100 , 101 , 102 , 103 , 104 , 105 , 106 , 107 , 108 , 109 , 110 , 111 , 112 , 113 ] are cited in the supplementary materials.…”