Flavanone and flavonoid hydroxylase genes regulate fiber color formation in naturally colored cotton

Using naturally colored cotton(NCC)can eliminate dyeing,printing and industrial processing,and reduce sewage discharge and energy consumption.Proanthocyanidins(PAs),the primary coloration components in brown fibers,are polyphenols formed by oligomers or polymers of flavan-3-ol units derived from anthocyanidins.Three essential structural genes for flavanone and flavonoid hydroxylation encoding flavanone-3-hydroxylase(F3H),flavonoid 3’-hydroxylase(F3’H)and flavonoid 3’5’-hydroxylase(F3’5’H)are initially committed in the flavonoid biosynthesis pathway to produce common precursors.The three genes were all expressed predominantly in developing fibers of NCCs,and their expression patterns varied temporally and spatially among NCC varieties.In GhF3Hi,GhF3’Hi and GhF3’5’Hi silenced lines of NCC varieties XC20 and ZX1,the expression level of the three genes decreased in developing cotton fiber,negatively correlated with anthocyanidin content and fiber color depth.Fiber color depth and type in RNAi lines changed with endogenous gene silencing efficiency and expression pattern,the three hydroxylase genes functioned in fiber color formation.GhF3H showed functional differentiation among NCC varieties and GhF3’H acted in the accumulation of anthocyanin in fiber.Compared with GhF3’H,GhF3’5’H was expressed more highly in brown fiber with a longer duration of expression and caused lighter color of fibers in GhF3’5’H silenced lines.These three genes regulating fiber color depth and type could be used to improve these traits by genetic manipulation.

Studies on Hereditary Properties of Colored Cotton in Xinjiang

[Objective] This study was to reveal the genetic characteristics of colored cotton varieties grown in Xinjiang. [Method] Five white upland and two white sea is- land cotton varieties were processed complete diallel crosses with five brown cotton varieties and five green cotton varieties respectively, constructing 96 F2 populations, and the population number of those in line with Mendel＇s law were counted. The individual fiber colors were statistically analyzed in each F2 generation. The cluster analysis was carried out to the parents based on their agronomic traits, and the SSR was used to analyze the genetic diversity of parents. [Result] Both green and brown fiber colors were determined by single nuclear gene; brown fiber color mainly presented dominant heredity, while green fiber color presented dominant, incomplete dominant or recessive heredity. The cluster analysis indicated that brown cotton vari- eties in Xinjiang had closer genetic relationships with Xinjiang-native upland cotton varieties than other upland cotton varieties in China, but distant from sea island cot- ton varieties; while green cotton varieties grown in Xinjiang showed distant genetic relationships with both native and other upland cotton varieties in China, and most distant from sea island varieties. SSR genetic diversity analysis of the parents showed that in all white/brown cross combinations, Xinluzao31 and Xincaimian11 showed the highest polymorphism while 293-ZM-2 and Xincaimian5 showed the low- est; in white/green cross combinations, Xinluzao31 and Green 85 showed the highest polymorphism while Xinluzao13 and Xingcaimian12 showed the lowest. [Conclusion] According to the genetic model and cluster analysis of colored cotton, the quality of cotton can be improved by hybridizing the colored cotton with Xinjiang native or in- land cotton varieties of China. This study provides germplasm resources and further study basis for the breeding of new colored cotton varieties, and materials to the fiber color gene mapping and cloning in future, as well as the technical assurance for the directional breeding of quality colored cotton varieties.

Study on the Genetics and Development of Fiber Pigments and Color Deviation After Wetting Process of Naturally Colored Cotton

The genetic control of fiber pigment color in naturally colored cotton was studied. The expression of brown and green fiber color was controlled by incompletely dominant single genes and incompletely dominant major genes, respectively. Production and accumulation of the fiber pigment were related to special expression of enzymatic genes for pigment synthesis in fiber cells. At the stage of fiber lengthening, naturally colored cotton, like white cotton, appeared purely white. But when fiber cell walls entered the thickening stage, pigment appeared by degrees. When the fiber was completely matured (on boll dehiscence), the color reached its darkest level. After wetting process treatment, the hues of the fiber pigment changed in regular patterns. The hue circle for brown and green cotton changed in the opposite direction with wetting process treatment. In general, the treated cotton color and luster became dark and vivid, and this trend provided the possibility for enhancing the fiber quality by suitable environmental friendly finishing. The analysis showed that the color and luster of the cotton may be controlled by a series of pigments which show different chemical performance.

Analysis of Genetic Polymorphic SSR Markers in Germplasm Resources of the Natural Colored Cotton

Short sequence repeats(microsatellite,SSR) and expressed sequence tags-SSR(EST-SSR) markers were employed to analyze the genetic diversity of natural colored cotton varieties.About

Effect of Eco-finishing on Naturally Colored Cotton

This paper studies desizing and polishing of naturally colored cotton with different enzyme. The reactivity of cellulases was measured. The percentage of decrement, bulkiness and color difference of fabrics both before and after eco-finishing were tested. The reasons were analyzed. The results indicates that the desizing of amylase can be applied on naturally colored cotton, and cellulases have polishing effect on it. Moreover eco-finishing with enzyme can provide many better properties to naturally colored cotton than that of normal finishing. Also this process has no pollution as enzyme can be degraded by bioreaction.

Genetics and Expression of the Brown Lint Gene in Colored Cotton

The major cotton grown commercially in the world is white lint,but recently many people prefer to have garments made by natural colored cotton.This can be used directly in textile industries,avoiding the complicated and unsafe processes of bleaching and dying,and thus it is eco-friendly.However,little is known about the heredity of the colored lint gene in colored cotton.In the present study,

New clues concerning pigment biosynthesis in green colored fiber provided by proteomics-based analysis

To separate the proteins related to pigment synthesis in green colored fiber （GCF）, we performed a comparative proteomic analysis to identify the differentially expressed proteins between green cotton fiber and a white near-isogenic line （NIL）. One differential spot identified as phenylocumaran benzylic ether redutase-like protein （PCBER） was expressed only in GCF, but was not found in white colored fiber （WCF） at any time points. Since PCBER was a key enzyme in lignans biosynthesis, total lignans were extracted from GCF and WCF and their content was determined by using a chromotropic acid spectrophotometric method. The results showed that total lignans content in GCF was significantly higher than that in WCF. The qPCR analysis for two PLR genes associated with lignans biosynthesis showed that the expression level of two genes was much higher in GCF than that in WCF at 24 and 27 days post anthesis （DPA）, which may be responsible for the higher lignans content in GCF. Our study suggested that PCBER and lignans may be responsible for the color difference between GCF and WCF. Additionally, p-dimethylaminocinnamaldehyde （DMACA） staining demonstrated that the pigment in GCF was not proanthocyanidins, and was different from that in brown colored fiber （BCF）. This study provided new clues for uncovering the molecular mechanisms related to pigment biosynthesis in GCF.