The Flavonoid Pathway Regulates the Petal Colors of Cotton Flower

Abstract

Although biochemists and geneticists have studied the cotton flower for more than one century, little is known about the molecular mechanisms underlying the dramatic color change that occurs during its short developmental life following blooming. Through the analysis of world cotton germplasms, we found that all of the flowers underwent color changes post-anthesis, but there is a diverse array of petal colors among cotton species, with cream, yellow and red colors dominating the color scheme. Genetic and biochemical analyses indicated that both the original cream and red colors and the color changes post-anthesis were related to flavonoid content. The anthocyanin content and the expression of biosynthesis genes were both increased from blooming to one day post-anthesis (DPA) when the flower was withering and undergoing abscission. Our results indicated that the color changes and flavonoid biosynthesis of cotton flowers were precisely controlled and genetically regulated. In addition, flavonol synthase (FLS) genes involved in flavonol biosynthesis showed specific expression at 11 am when the flowers were fully opened. The anthocyanidin reductase (ANR) genes, which are responsible for proanthocyanidins biosynthesis, showed the highest expression at 6 pm on 0 DPA, when the flowers were withered. Light showed primary, moderate and little effects on flavonol, anthocyanin and proanthocyanidin biosynthesis, respectively. Flavonol biosynthesis was in response to light exposure, while anthocyanin biosynthesis was involved in flower color changes. Further expression analysis of flavonoid genes in flowers of wild type and a flavanone 3-hydroxylase (F3H) silenced line showed that the development of cotton flower color was controlled by a complex interaction between genes and light. These results present novel information regarding flavonoids metabolism and flower development.

The Mating System of the Wild-to-Domesticated Complex of Gossypium hirsutum L. Is Mixed

“…Flowers are white, hermaphrodite, cup shaped, with a single central style surrounded at the bottom by stamens ( Meade, 1918 ; Smith and Cothren, 1999 ). Some plants exhibit flowers with a colored disk inside of the base of the cup that ranges from deep red to light yellow ( Tan et al, 2013 ). Flowers remain open between 8 and 11 h; at the start of the day, they are all white and when they close the sepals start turning pink at the base ( Smith and Cothren, 1999 ).…”

Factor Analysis of MYB Gene Expression and Flavonoid Affecting Petal Color in Three Crabapple Cultivars

“…Crabapples, belonging to the Malus genus, are excellent ornamental and economic germplasm resources throughout the world, with diverse color variations in the fruits, flowers and leaves under the direct influence of flavonoids (Liu et al, 2011 ; Tan et al, 2013 ). The pigmentation of flowers is important for their ornamental value, with a vital role in sightseeing.…”

The Regulation of Floral Colour Change in Pleroma raddianum (DC.) Gardner

“…In P. raddianum, a preliminary experiment showed that when the plants were maintained indoor under low light irradiance, the flowers did not homogenously turn from white to pink, and fell in 24 h ( Figure S3 ), suggesting a regulatory role of light in flower anthocyanin accumulation in this species. Reinforcing our observation, in cotton flowers ( Gossypium sp., Malvaceae), which turn from white to pink, gene expression analysis has shown that light and shade regulate anthocyanin biosynthesis, in particular the ANS gene [ 45 ]. Likewise, Viola cornuta flowers did not undergo colour change in darkness [ 13 ].…”