title: An apple B-box protein, MdCOL11, is involved in UV-B- and temperature-induced anthocyanin biosynthesis.
abstract: Our studies showed that an apple B-box protein, MdCOL11, the homolog of AtBBX22, is involved in UV-B- and temperature-induced anthocyanin biosynthesis in apple peel. Anthocyanin is responsible for the red pigmentation in apple peel and a R2R3 MYB gene, MdMYBA/1/10, a homolog of MdMYBA, controls its accumulation. Arabidopsis PAP1 is under the control of a series of upstream factors involved in light signal transduction and photomorphogenesis, such as ELONGATED HYPOCOTYL 5 (HY5) and B-box family (BBX) proteins. In this study, we identified and characterized the homolog of Arabidopsis BBX22 in apple, designated as MdCOL11. Overexpression of MdCOL11 in Arabidopsis enhanced the accumulation of anthocyanin. In apples, MdCOL11 was differentially expressed in all tissues, with the highest expression in petals and the lowest expression in the xylem. Transcripts of MdCOL11 noticeably accumulated at the ripening stage, concomitant with increases in the expressions of anthocyanin biosynthesis-related genes. In an in vitro treatment experiment, MdCOL11 was upregulated in an ultra-violet (UV)-B- and temperature-dependent manner, together with the inductions of anthocyanin biosynthesis-related genes and anthocyanin accumulation in apple peel. Furthermore, a dual-luciferase assay indicated that (1) MdCOL11 regulated the expression of MdMYBA and (2) MdCOL11 was a target of MdHY5. Taken together, our results suggest that MdCOL11 is involved in MdHY5-mediated signal transduction and regulates anthocyanin accumulation in apple peel, which sheds new light on anthocyanin accumulation in apples.
authors: NARO Institute of Fruit Tree Science, Tsukuba, Ibaraki, 305-8605, Japan.
authors: Songling
authors: S
authors: Bai
authors: Takanori
authors: T
authors: Saito
authors: Chikako
authors: C
authors: Honda
authors: Yoshimichi
authors: Y
authors: Hatsuyama
authors: Akiko
authors: A
authors: Ito
authors: Takaya
authors: T
authors: Moriguchi
mesh_terms: D000595:Amino Acid Sequence; D000872:Anthocyanins / Q000096:biosynthesis*; D017360:Arabidopsis / Q000235:genetics / Q000378:metabolism; D035264:Flowers / Q000235:genetics / Q000378:metabolism; D005638:Fruit / Q000235:genetics / Q000378:metabolism; D020869:Gene Expression Profiling; D018506:Gene Expression Regulation, Plant / Q000528:radiation effects*; D027845:Malus / Q000145:classification / Q000235:genetics* / Q000378:metabolism; D008957:Models, Genetic; D008969:Molecular Sequence Data; D000073718:Pancreatitis-Associated Proteins; D010802:Phylogeny; D010940:Plant Proteins / Q000235:genetics* / Q000378:metabolism; D018547:Plant Stems / Q000235:genetics / Q000378:metabolism; D030821:Plants, Genetically Modified; D020133:Reverse Transcriptase Polymerase Chain Reaction; D017386:Sequence Homology, Amino Acid; D013696:Temperature; D014466:Ultraviolet Rays
chemical_list: D000872:Anthocyanins; D000073718:Pancreatitis-Associated Proteins; D010940:Plant Proteins; C000612141:REG3A protein, human