Genetic Resources

Dynamic Changes of Phenolic Compounds and Their Associated Gene Expression Profiles Occurring during Fruit Development and Ripening of the Donghong Kiwifruit

“…Kiwifruit is widely recognized as a valuable fruit because of its nutritional and healthy attributes. − In particular, the red-fleshed kiwifruits are rich sources of antioxidants improving human health and longevity . Phenolic compounds are the most widely distributed secondary metabolites in the plant kingdom with antioxidant capacity .…”

“…Anthocyanin is a kind of end-product of the flavonoid pathway. , Anthocyanins have been the subject of extensive studies during the past decades. ,, To date, a total of 434 major anthocyanins have been isolated and characterized from 639 land plant species, according to the aglycone and decoration moiety. , Pelargonidin, cyanidin, peonidin, delphinidin, petunidin, and malvidin constitute six core structures of anthocyanin aglycones. ,,, Major anthocyanins are distinguished by different hydroxylation patterns, i.e., the glycosyl, acyl, and phenylacyl moieties . Previous studies have shown that the fresh color of red kiwifruits is due to different concentrations and proportions of anthocyanins. , The total anthocyanidin accumulation pattern in the Donghong kiwifruit (Figure B) was consistent with that of the red-fleshed Hongyang kiwifruit . Cy-xyl.gal and Cy-gal.…”

“…Kiwifruit ( Actinidia Lindl.) is a perennial deciduous warm-temperate fruit crop with the center of evolution being southwestern China . The kiwifruit has long been regarded as “the king of fruits” because it is an excellent source of multiple sugars, organic acids, vitamins (especially vitamin C), minerals, dietary fiber, carotenoids, chlorophylls, phenolic compounds, etc. , Phenolic compounds, characterized by an aromatic ring in combination with one or more hydroxyl substituents, are the most widely distributed secondary metabolites in the plant kingdom. , More than 10,000 phenolic compounds have been identified in plants so far. , They are mainly divided into phenolic acids, flavonoids, tannins, stilbenes, coumarins, and lignans according to chemical structure and can be found in free, bound, and soluble forms. , …”

“…The pigmentation pattern of red-fleshed A. chinensis species is ascribed to a high concentration of anthocyanins, primarily restricted to the inner pericarp (endocarp). , Three cyanidin-based anthocyanins, i.e., cyanidin 3- O -[2- O -(β-xylosyl)-β-galactoside] (Cy-xyl.gal. ), cyanidin 3- O -β-galactoside (Cy-gal.)…”

“…AcDFR 1 is expressed at low levels in the Hongyang kiwifruit, and AcDFR 2 is expressed at high levels, but the expression levels of both AcDFR 1 and AcDFR 2 increase at later developmental stages . Hongyang is the most widespread and studied cultivar in the red-fleshed kiwifruit cultivars . Therefore, most of the literature on red-fleshed cultivar is focused on Hongyang.…”