Fine mapping of the Ca3GT gene controlling anthocyanin biosynthesis in mature unripe fruit of Capsicum annuum L.

Peng

et al. 2022

Preprint

Rind color is an economically important agronomic trait in eggplant that impacts consumer preferences. However, the gene(s) regulating eggplant rind color have not been characterized. In this study, bulked segregant analysis (BSA) and kompetitive allele-specific PCR (KASP) were employed to identify a candidate gene for eggplant rind color through constructing an F2 population generated from a cross between 'BL01' (green pericarp) and 'B1' (white pericarp). Genetic analysis of rind color revealed that a single dominant gene controls green color of eggplant peel. Pigment content measurement and cytological observations demonstrated that chlorophyll and carotenoid content and the number of chloroplasts and thylakoids in BL01 were higher than in B1. Using a BSA-seq method and a recombinant mapping strategy in F2 plants, a candidate gene (EGP19168.1) was fine-mapped to a 20.36 Kb interval on chromosome 8. The gene is predicted to encode the two-component response regulator-like protein Arabidopsis pseudo-response regulator2 (APRR2). Subsequently, allelic sequence analysis revealed that a single-base deletion in white-skinned eggplant led to a premature termination codon. A credible molecular marker closely linked to the candidate gene was developed to genotype 45 diverse eggplant germplasms, which could predict the trait of rind color (green and white) with a 91.1% accuracy rate. This study will be valuable for molecular marker-assisted selection in eggplant breeding and provides theoretical foundation for analyzing the formation mechanism of eggplant peel color.

Section: Discussionsupporting

confidence: 86%

Fine mapping and identification of SmAPRR2 regulating rind color in eggplant (Solanum melongena L.)

Fang

Peng

et al. 2022

Preprint

“…For example, in petunia, the WRKY transcription factor, PhPH3, and MBW complex regulate the expression of the two proton pumps (PhPH1 and PhPH5) that are further responsible for vacuolar acidification, thereby imparting the red color to the anthocyanins ( Verweij et al, 2016 ). An anthocyanin biosynthesis gene, Ca3GT , has been finely located in the pepper chromosome 10, and it is a strong candidate gene for anthocyanin biosynthesis in mature and immature pepper fruits ( Liu J. et al, 2020 ).…”

Section: Introductionmentioning

confidence: 99%

Genome-Wide Characterization and Anthocyanin-Related Expression Analysis of the B-BOX Gene Family in Capsicum annuum L.

et al. 2022

The transcription factors, B-box (BBX), belong to a subfamily of the zinc finger family of proteins and exhibit multiple biological functions in plant growth, development, and abiotic stress response pathways. In this study, a total of 23 CaBBX members were identified using the pepper reference genome database. According to the gene structure, conserved domains, and the phylogenetic tree, 23 CaBBX genes were divided into four groups, wherein the analysis of the promoter region indicated the presence of cis-acting elements related to plant development, hormones, and stress response. Interspecies collinearity analysis showed that the CaBBXs had three duplicated gene pairs, and the highest gene density was found on chromosomes 2 and 7. Transcriptome RNA-seq data and quantitative polymerase chain reaction (qRT-PCR) analysis of pepper plants spanning the entire period showed that more than half of the CaBBX genes were widely expressed in diversity tissues of pepper. Co-expression network analysis indicated that the CaBBXs and the anthocyanin structural genes had a close co-expression relationship. Thus, it was reasonably speculated that the CaBBX genes may be involved in the regulation of anthocyanin biosynthesis. Overall, this study involved the genome-wide characterization of the CaBBX family and may serve as a solid foundation for further investigations on CaBBX genes involved in the anthocyanin synthesis mechanisms and development in pepper.

“…Although the abovementioned trait is important for the pepper industry, very few studies have focused on this issue. In contrast, many researchers have made efforts to disclose the mechanism of consistently purple fruits at the mature green stage [38,[40][41][42]. In this study, a natural mutant was discovered in our experimental field, which bears fruits that partially turn purple when exposed to sunlight.…”

Section: Uv-b Effectively Induced Anthocyanin Biosynthesis In the Pee...mentioning

confidence: 94%

Identification of the Regulatory Genes of UV-B-Induced Anthocyanin Biosynthesis in Pepper Fruit

Liu

et al. 2022

IJMS

Self Cite

Fruit peels of certain pepper (Capsicum annum L.) varieties accumulate a large amount of anthocyanins and exhibit purple color under medium-wave ultraviolet (UV-B) conditions, which severely impacts the commodity value of peppers. However, the regulatory mechanism of the above process has not been well studied so far. To explore which key genes are involved in this regulatory mechanism, pepper variety 19Q6100, the fruit peels of which turn purple under UV-B conditions, was investigated in this study. Transcription factors with expression levels significantly impacted by UV-B were identified by RNA-seq. Those genes may be involved in the regulation of UV-B-induced anthocyanin biosynthesis. Yeast one-hybrid results revealed that seven transcription factors, CabHLH143, CaMYB113, CabHLH137, CaMYBG, CaWRKY41, CaWRKY44 and CaWRKY53 directly bound to the putative promotor regions of the structural genes in the anthocyanin biosynthesis pathway. CaMYB113 was found to interact with CabHLH143 and CaHY5 by yeast two-hybrid assay, and those three genes may participate collaboratively in UV-B-induced anthocyanin biosynthesis in pepper fruit. Virus-induced gene silencing (VIGS) indicated that fruit peels of CaMYB113-silenced plants were unable to turn purple under UV-B conditions. These findings could deepen our understanding of UV-B-induced anthocyanin biosynthesis in pepper.