The R2R3-MYB transcription factor GaPC controls petal coloration in cotton
Caiping Cai,
Fan Zhou,
Weixi Li,
Yujia Yu,
Zhihan Guan,
Baohong Zhang,
Wangzhen Guo
Affiliations
Caiping Cai
State Key Laboratory of Crop Genetics & Germplasm Enhancement and Utilization, Nanjing Agricultural University, Nanjing 210095, Jiangsu, China; Engineering Research Center of Ministry of Education for Cotton Germplasm Enhancement and Application, Nanjing Agricultural University, Nanjing 210095, Jiangsu, China
Fan Zhou
State Key Laboratory of Crop Genetics & Germplasm Enhancement and Utilization, Nanjing Agricultural University, Nanjing 210095, Jiangsu, China; Engineering Research Center of Ministry of Education for Cotton Germplasm Enhancement and Application, Nanjing Agricultural University, Nanjing 210095, Jiangsu, China
Weixi Li
State Key Laboratory of Crop Genetics & Germplasm Enhancement and Utilization, Nanjing Agricultural University, Nanjing 210095, Jiangsu, China; Engineering Research Center of Ministry of Education for Cotton Germplasm Enhancement and Application, Nanjing Agricultural University, Nanjing 210095, Jiangsu, China
Yujia Yu
State Key Laboratory of Crop Genetics & Germplasm Enhancement and Utilization, Nanjing Agricultural University, Nanjing 210095, Jiangsu, China; Engineering Research Center of Ministry of Education for Cotton Germplasm Enhancement and Application, Nanjing Agricultural University, Nanjing 210095, Jiangsu, China
Zhihan Guan
State Key Laboratory of Crop Genetics & Germplasm Enhancement and Utilization, Nanjing Agricultural University, Nanjing 210095, Jiangsu, China; Engineering Research Center of Ministry of Education for Cotton Germplasm Enhancement and Application, Nanjing Agricultural University, Nanjing 210095, Jiangsu, China
Baohong Zhang
Department of Biology, East Carolina University, Greenville, NC 27858, USA; Corresponding authors.
Wangzhen Guo
State Key Laboratory of Crop Genetics & Germplasm Enhancement and Utilization, Nanjing Agricultural University, Nanjing 210095, Jiangsu, China; Engineering Research Center of Ministry of Education for Cotton Germplasm Enhancement and Application, Nanjing Agricultural University, Nanjing 210095, Jiangsu, China; Corresponding authors.
Although a few cases of genetic epistasis in plants have been reported, the combined analysis of genetically phenotypic segregation and the related molecular mechanism remains rarely studied. Here, we have identified a gene (named GaPC) controlling petal coloration in Gossypium arboreum and following a heritable recessive epistatic genetic model. Petal coloration is controlled by a single dominant gene, GaPC. A loss-of-function mutation of GaPC leads to a recessive gene Gapc that masks the phenotype of other color genes and shows recessive epistatic interactions. Map-based cloning showed that GaPC encodes an R2R3-MYB transcription factor. A 4814-bp long terminal repeat retrotransposon insertion at the second exon led to GaPC loss of function and disabled petal coloration. GaPC controlled petal coloration by regulating the anthocyanin and flavone biosynthesis pathways. Expression of core genes in the phenylpropanoid and anthocyanin pathways was higher in colored than in white petals. Petal color was conferred by flavonoids and anthocyanins, with red and yellow petals rich in anthocyanin and flavonol glycosides, respectively. This study provides new insight on molecular mechanism of recessive epistasis, also has potential breeding value by engineering GaPC to develop colored petals or fibers for multi-functional utilization of cotton.