The apple (Malus Domestica Borkh.) It is one of the most productive and economically essential fruits of temperate regions. Apple fruit color development is an important goal for both researchers and researchers, as consumers associate bright-colored red apples with ripeness and good flavor. In these recent years, significant progress has been made in research on the development of apple color, but its development mechanism has not been systematically analyzed by aspects of genetics, transcription, or environmental factors. 
Here, we summarize the research on apple coloring, including the development of critical genomic databases to identify essential genes and genomic regions, genetic and transcriptional factors that regulate pigment accumulation, environmental factors that influence anthocyanin synthesis, and current progress. Reproductive red-red skin. And pulp apples. We describe key transcription factors, such as MYOB, bHLH, and WD40, which regulate anthocyanin synthesis and fruit color development in golden delicious apples. We shall also discuss the regulation of apple color by external environmental factors such as light, temperature, and water. This review provides information on the molecular mechanisms underlying anthocyanin biosynthesis in apples. This information will provide an essential guide for breeding high-quality red-skinned, red-fleshed apple varieties. The apple (Malus Domestica Borkh.) is one of the most productive and economically essential fruits in temperate regions (Velasco et al., 2010). It is popular among growers and consumers due to its solid ecological adaptability and good nutritional value (Eberhardt et al.; Boyer and Liu, 2004; Hyson, 2011). accorded to World Apple Review (2018) statistics, apples accounted for 12.26% of global fruit production between 2012 and 2014, second only to bananas and citrus (World Apple Review, 2018). Accorded to the Food and Agriculture Organization of the United Nations (FAO), the world production of apples in 2015 exceeded 80 million tons (FAO I, 2015). The main apple cultivars can be hardly divided into red varieties such as "Red Delicious," "Fuji," and "Royal Gala" and colorless varieties such as "Golden Delicious," "Granny Smith," and "Orin." Consumers associate red apples with ripeness and good flavor. As a result, red apple varieties tend to have better marketability and more economic value (King and Cliff; Ban et al., 2007; Wang et al., 2018a). Therefore, the development of fruit color is one of the main objectives of apple growers and also researchers. Anthocyanins mainly determine the Fruit color, an important class of secondary metabolites synthesized in higher plants. Anthocyanins show a different color depending on the pH in the cells, so the leaves, flowers, fruits, and seeds of plants have different colors, such as purple, red, or blue. Anthocyanins are actually the glycosylated derivatives of anthocyanidins and are being generated by forming a glycosidic bond between anthocyanidin and various monosaccharides (glucose, galactose, rhamnose, xylose, or arabinose). In apples, cyanidin is the primary type of anthocyanidin. It combines mainly with galactose to form cyanidin-3-galactoside, representing approximately 80% of anthocyanins (Treutter, 2001). The biosynthetic pathway of anthocyanins in plants has been thoroughly investigated. The metabolic pathway is highly conserved across species, and genes encoding key enzymes have been cloned and identified. In addition to the structural genes involved in this biosynthetic pathway, transcription factors (T.F.s) that regulate anthocyanin synthesis have also drawn the attention of researchers. Many T.F. families related to anthocyanin synthesis, including MYB, bHLH, WD40, WRKY, and zinc finger proteins, have been identified and isolated from various plants (Walker et al., 1999; Borevitz et al., 2000; Liu et al., 2019). A ternary protein complex comprising MYB and WD40 (MBW) proteins is essential in regulating anthocyanin synthesis, and MYBs are the main genes. The first MYB genes identified and isolated from apples were MdMYB1 (MdMYBA) and MdMYB10, which encode T.F.s that regulate anthocyanin synthesis in red-skinned apple red-fleshed apples, respectively. Interestingly, identifying these genes predates the sequencing and assembly of the apple genome. 
The complete sequence of the apple genome, approximately 742.3 Mb, was initially reported by Velasco et al. Of this first draft genome sequence, 603.9 Mb were assembled, and 593.3 Mb were mapped to 17 chromosomes. Since it was the first sequenced, the apple genome has been continuously updated. High-quality apple genomes were assembled using the latest sequencing technologies or homozygous samples (Li et al., 2016; Daccord et al., 2017). Since its genome has been fully sequenced, the apple has become a kind of perennial model fruit tree, and there has been a rapid increase in research on color development, strength, flavor, storage attributes, and other apple traits. With the continuous improvements of the apple genome sequence and the development of genetic maps, research on the apple fruit color development has entered a new era. This provided new opportunities to analyze the genetic basis of red skin and red meat traits. Furthermore, with biotechnological tools, molecule-assisted selection and molecule-assisted breeding are progressively applied to apple cultivation. These methods can significantly reduce the breeding period and improve the reproductive efficiency of red-skinned and red-fleshed apple varieties. This review focuses on the development of fruit color in the red gala apple. This review summarizes recent studies on the genetic basis of apple fruit color and discusses fruit color development's transcriptional and environmental regulation. We will also review the progress of current research and breeding programs for red-skinned and red-fleshed apples. The general objective of this review is to provide valuable information on the molecular mechanisms of anthocyanin biosynthesis and the improvement of the red apple.
Genetics and genomics of apple color development
Genomics is one of the fastest developing emerging biology, medicine, and agriculture disciplines. The genomes of most fruit trees have already been sequenced. With the falling cost of sequencing, it is easy for breeders to obtain information on molecular markers. 
This information can understand how fruit trees adapt to the environment and continue to reshape or genetically modify fruit trees to meet future agricultural needs (McCouch et al., 2013). Transcriptional regulation of fruit color in apple. A number of structural enzymes catalyze the biosynthesis of anthocyanins, and various T.F.s and transcription complexes regulate the expression of the coding genes. The transcriptional regulation of anthocyanin synthesis was first studied in model plants such as maize, Arabidopsis, and petunia more than 30 years ago, but recent research has been focused on this process on apple fruit trees. The transcription factors regulate the expression of most genes by binding to cis-elements in their promoter regions. Some T.F. genes Environmental regulation of fruit color in apple. Secondary plant metabolism evolved during interactions between plants and biotic/abiotic environmental factors. Secondary metabolites, such as flavonoids, terpenoids, and alkaloids, play an essential role in plant protection and competitiveness and help coordinate the relationship between plants and the environment. In addition to genetic and transcriptional regulation, temperature, water, sugars, and the plant Improvement of apples with red skin and red pulp. With the growing demand for high-quality apples, fruit with a bright color, rich aroma, and excellent flavor has become an essential focus for breeders. Associate red apple varieties with ripeness, consumers, and good taste (King et al., 2002; Ban et al., 2007). Furthermore, the red-fleshed apple as a new fruit has attracted more attention from researchers and breeders in recent years (Wang et al., 2018a). The complexity of the regulatory mechanism of anthocyanin biosynthesis in apples is the embodiment of germplasm diversity. 
The continuous development of molecular biology technologies and further research will provide further details on the regulation of anthocyanin synthesis and the development of fruit color. This information will help improve the anthocyanin content and the general quality of the fruit. However, the mechanisms of regulation of anthocyanin synthesis are pretty complex and highly.
Benefits of apple for skin
There are numerous naturally occurring fruits and vegetables that are very useful for us: oranges, apples, papaya, berries, and lemons, to name a few. As a cliché, the saying "an apple a day keeps the doctor away" is entirely accurate as the fruit includes several essential nutrients and vitamins that protect us from various diseases. Some researchers found out that an apple a day can also keep skin dull! We have discovered how apples benefit the skin, and we can't wait to share them with you! If you are someone who has an apple in their lunch box, chances are you already have beautiful skin! For those who don't like apples so much, look at these delicious ways to include apples in your daily diet at the end of this article.
Glowing skin
Rich in vitamins A, B, and C complexes, apples benefit the skin by helping to eliminate pathogens and excess oil. Eating apples regularly can brighten the skin and correct uneven skin tone. The antioxidants in this fruit accelerate skin cell rejuvenation and help keep skin healthy and glowing. How to use: In addition to including it in your diet, you can also make an apple face mask by grating green apple and applying it to your face. This will maintain the skin's natural pH balance and keep common skin problems at bay.
Prevents premature aging
Sun exposure, pollution, and other environmental stressors cause skin damage from free radicals. These free radicals destroy collagen and elastin fibers in the skin to make fine lines and wrinkles appear earlier and more prominently. 
Vitamin C is a powerful antioxidant that can help tackle the problem of premature aging. Apples contain a lot of vitamin C and, if consumed regularly, can reduce the first signs of skin aging. How to use: To reap the benefits of apple for the skin, extract the juice from an apple and apply it all over the face and neck with a cotton ball. Let it dry and then rinse with water, do it 2-3 times a week for best results.
Treat acne and blemishes
Did you know that regular consumption of green apples can help control the appearance of acne and pimples? If you have active acne, dark spots, or spots, they can also be corrected with the help of apples. If chemical-based acne creams don't help, this nutrient-rich fruit may be the answer to your prayers. How to use: Mash a slice of apple and mix it with a spoonful of milk. Apply this mixture to the affected areas to relieve acne, blemishes, and dark spots.
Moisturizes the skin
Hydration is the real secret to soft, supple, and radiant skin. While it is essential to consume the recommended daily intake of water, it alone may not be able to hydrate the entire body. It is vital to include fruits and vegetables that moisturize the skin. The high water content in apples makes them an excellent choice for maintaining hydration levels. 
How to use: Cut an apple into thin slices and apply it immediately all over the face to get all the benefits of apples for the skin. Let it sit for 15-20 minutes, and sprinkle some water for smooth, hydrated skin.
Offers U.V. protection
When we say one of the benefits of apples for the skin is U.V. protection, we don't mean that you can skip sunscreen. Certain nutrients in apples offer protection from the sun's harsh rays. Apples can be used in the treatment of sunburn. It helps soothe the area and soothes the irritated skin and the burning sensation. How to use: grate an apple to obtain the pulp, add a teaspoon of glycerin and mix until a smooth paste is obtained. Apply this paste evenly on the face and neck, leave for 15 minutes, then rinse with cold water.
Reduces dark circles and puffy eyes
Another benefit of apples for the skin is reducing dark circles and puffy eyes. Lack of sleep, stress and other reasons can cause pigmentation under the eyes. Apples can help lighten these dark circles and make the under-eye area brighter. How to use: Cut the apple slices, place them under the eye and relax them for 20 minutes. You can also boil a few pieces of apple in water. Once they are smooth, squeeze them and apply them under the eyes to lighten the pigmentation. The apple fruits are one of the most beneficial fruits in the natural resource category. Their presence in our daily diets is a must-have thing and should not be forgotten. Importers and exporters of fruit know that the apple fruit is an excellent option for business since it can sell pretty much everywhere and quickly too. Our company has been growing fruits for more than a decade, and now we aim to reach to provide a larger amount of the supplies to the other countries. Please fill out an inquiry on our website for further information and questions. Our assistants are available 24 hours a day to provide you with full service.
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