Pepper Berry Colour: Molecular Inheritances and Colorant Biosynthesis

Chui Chan^*
*Correspondence: Chui Chan, Department of Crop Science, Lishui University of Agricultural and Forestry Sciences, Lishui, China, Email:

Keywords

Anthocyanin biosynthesis • Pepper berry color • Molecular inheritance

Introduction

In the case of pepper berries, the molecular inheritances of anthocyanin pigments determine the specific shade of red exhibited. The color of these pigments is influenced by several factors, including the type and concentration of anthocyanins, as well as the pH and co-pigments present in the cellular environment. The biosynthesis of colorants in pepper berries involves a complex series of biochemical reactions. These reactions are mediated by a network of enzymes that catalyze the transformation of precursor molecules into anthocyanins. The key steps in this process include the production of flavonoids, the modification of flavonoids to form anthocyanidins, and the glycosylation of anthocyanidins to produce anthocyanins.

Flavonoids serve as the building blocks for anthocyanin synthesis. They are derived from a class of molecules called phenylpropanoids. The phenylpropanoid pathway involves a series of enzymatic reactions that convert phenylalanine, an amino acid, into various intermediates, eventually leading to the production of flavonoids. Flavonoid biosynthesis is influenced by both genetic and environmental factors, which can affect the concentration and composition of these compounds in pepper berries.

Once flavonoids are synthesized, they can undergo further modifications to form anthocyanidins, the core structure of anthocyanins. Enzymes such as flavonoid 3'-hydroxylase, flavonoid 3',5'-hydroxylase, and dihydroflavonol 4-reductase play critical roles in converting flavonoids into different anthocyanidin forms. The specific anthocyanidin produced determines the color of the resulting anthocyanin pigment [1]. After the formation of anthocyanidins, glycosylation occurs, where sugar molecules are attached to the anthocyanidin structure. This step is crucial for stabilizing and solubilizing the pigment. Enzymes called glycosyltransferases are responsible for attaching the sugar moieties to anthocyanidins, resulting in the formation of anthocyanins. The type and number of sugar molecules attached also influence the stability and color of the final pigment.

Literature Review

The biosynthesis of colorants in pepper berries is tightly regulated by a combination of genetic and environmental factors. Gene expression plays a crucial role in determining the presence and activity of enzymes involved in colorant biosynthesis. Various transcription factors, such as MYB, bHLH, and WD40, regulate the expression of genes encoding these enzymes. Environmental factors such as light, temperature, and nutrient availability can also impact colorant biosynthesis.

Color is a fascinating aspect of the natural world, captivating our senses and influencing our emotions. From the vibrant hues of flowers to the deep pigmentation of fruits, colors in nature are products of complex molecular processes. One such intriguing color is the pepper berry color, found in various plant species, particularly in certain pepper berries. The mesmerizing purple and black shades of pepper berries are not just random occurrences; they are a result of molecular inheritances and intricate colorant biosynthesis pathways. In this article, we delve into the world of pepper berry color, exploring the underlying molecular mechanisms responsible for its beautiful pigmentation. Pepper berries are a common sight in several regions across the globe, with species like Piper nigrum and Schinus molle being prominent examples. These berries are known for their distinct coloration, ranging from deep purple to dark black. The color is mainly localized in the berry's skin and is attributed to a class of compounds known as anthocyanins [2,3]. Anthocyanins are water-soluble pigments responsible for the red, blue, and purple colors observed in various fruits, flowers, and leaves. They play essential roles in attracting pollinators, protecting plants from environmental stresses, and acting as antioxidants.

The inheritance of color traits in pepper berries is a result of both genetic and environmental factors. Genetic inheritance plays a significant role in determining the presence and abundance of colorant compounds [4], while environmental conditions can influence the intensity and hue of the pepper berry color.The color of pepper berries is determined by a complex set of genes involved in anthocyanin biosynthesis. These genes control the production of enzymes responsible for catalyzing the conversion of colorless compounds into anthocyanins. Inheritance patterns of these genes from parent plants to offspring result in various shades of pepper berry color [5]. Some pepper berry varieties carry dominant alleles that promote high anthocyanin production, leading to darker colors, while others may possess recessive alleles, resulting in lighter or less pigmented berries.

Discussion

While genetics plays a fundamental role, the environment can also influence the final appearance of pepper berries. Factors such as sunlight exposure, temperature fluctuations, and soil nutrient availability can impact the expression of color genes and the biosynthesis of anthocyanins. Cooler temperatures and increased exposure to Ultraviolet (UV) light, for instance, have been shown to enhance the production of anthocyanins, intensifying the berry's color.The biosynthesis of anthocyanins in pepper berries is an intricate process involving multiple enzymatic reactions. Understanding these pathways sheds light on the molecular mechanisms that govern pepper berry coloration. The first step in anthocyanin biosynthesis is the formation of phenylpropanoids from phenylalanine, an amino acid derived from the shikimate pathway. Enzymes such as Phenylalanine Ammonia-Lyase (PAL) and cinnamate 4-hydroxylase (C₄H) are involved in this step.Phenylpropanoids are then converted into chalcones by the action of enzymes CHS and CHI. Chalcones are the key intermediates in anthocyanin biosynthesis.

Pepper berries, derived from the Schinus molle tree, are small fruits widely recognized for their vibrant and distinctive color. The unique hue of pepper berries, often described as a combination of red, pink, and purple, has captivated researchers and enthusiasts alike. Understanding the molecular inheritances and colorant biosynthesis responsible for this striking pigment can shed light on the botanical world's intricate processes and offer insights into potential applications in various fields [6]. The captivating color of pepper berries can be attributed to the presence of a group of pigments known as anthocyanins. Anthocyanins are water-soluble pigments found in many plant tissues, including fruits, flowers, and leaves. These compounds are responsible for an array of colors, ranging from red and purple to blue. The unique combination of anthocyanins found in pepper berries contributes to their distinct pepper berry color.

Conclusion

Anthocyanins belong to the flavonoid family of compounds, which are derived from phenylpropanoid metabolism. The biosynthesis of anthocyanins involves a complex series of enzymatic reactions, starting from the precursor molecule, phenylalanine. The first committed step in this pathway is the conversion of phenylalanine to cinnamic acid by the enzyme Phenylalanine Ammonia-Lyase (PAL). Subsequent enzymatic reactions lead to the synthesis of anthocyanins, culminating in the formation of specific anthocyanin molecules responsible for the pepper berry color..

Acknowledgement

Not applicable.

Conflict of Interest

There is no conflict of interest by author.

References

1. Luo, Xiu-Ju, Jun Peng and Yuan-Jian Li. "Recent advances in the study on capsaicinoids and capsinoids." Euro J Pharmacol 650 (2011): 1-7.

Google Scholar, Crossref, Indexed at

2. Suzuki, Miho, Sachiko Takahashi, Takanori Kondo and Hideo Dohra, et al. "Plastid proteomic analysis in tomato fruit development." PLoS One 10 (2015): e0137266.

Google Scholar, Crossref, Indexed at

3. Ma, Changqing, Bowen Liang, Bo Chang and Jiuying Yan, et al. "Transcriptome profiling of anthocyanin biosynthesis in the peel of ‘Granny Smith’apples (Malus domestica) after bag removal." BMC Genomics 20 (2019): 1-18.

Google Scholar, Crossref, Indexed at

4. Kim, Seungill, Minkyu Park, Seon-In Yeom and Yong-Min Kim, et al. "Genome sequence of the hot pepper provides insights into the evolution of pungency in Capsicum species." Nat Genetics 46 (2014): 270-278.

Google Scholar, Crossref, Indexed at

5. Wu, Yi, Sigal Popovsky‐Sarid, Yury Tikunov and Yelena Borovsky, et al. "CaMYB12‐like underlies a major QTL for flavonoid content in pepper (C. annuum) fruit." New Phytol 237 (2023): 2255-2267.

Google Scholar, Crossref, Indexed at

6. Lightbourn, Gordon J., Robert J. Griesbach, Janet A. Novotny and Beverly A. Clevidence, et al. "Effects of anthocyanin and carotenoid combinations on foliage and immature fruit color of C. annuum L." J Heredity 99 (2008): 105-111.

Google Scholar, Crossref, Indexed at