Molecular cloning and functional analysis of a UV-B photoreceptor gene, MdUVR8 (UV Resistance Locus 8), from apple.
UVR8 (UV Resistance Locus 8) is an ultraviolet-B (UV-B; 280-315nm) light receptor that is involved in regulating many aspects of plant growth and development. UV-B irradiation can increase the development of flower and fruit coloration in many fruit trees, such as grape, pear and apple. Previous investigations of the structure and functions of UVR8 in plants have largely focused on Arabidopsis. Here, we isolated the UVR8 gene from apple (Malus domestica) and analyzed its function in transgenic Arabidopsis. Genomic and protein sequence analysis showed that MdUVR8 shares high similarity with the AtUVR8 protein from Arabidopsis, including the conserved seven-bladed β-propeller, the C27 region, the 3 "GWRHT" motifs and crucial amino-acid residues (14 Trps, 2 Args). A point mutation prediction and three-dimensional structural analysis of MdUVR8 indicated that it has a similar structure to AtUVR8 and that the crucial residues are also important in MdUVR8. In terms of transcript levels, MdUVR8 expression was up-regulated by UV-B light, which suggests that its expression follows a 24-h circadian rhythm. Using heterologous expression of MdUVR8 in both uvr8-1 mutant and wild-type (WT) Arabidopsis, we found that MdUVR8 regulates hypocotyl elongation and gene expression under UV-B light. These data provide functional evidence for a role of MdUVR8 in controlling photomorphogenesis under UV-B light and indicate that the function of UVR8 is conserved between Arabidopsis and apple. Furthermore, we examined the interaction between MdUVR8 and MdCOP1 (constitutive photomorphogenic1) using a yeast two-hybrid assay and a co-immunoprecipitation assay. This interaction provides a direction for investigating the regulatory mechanisms of the UV-B-light pathway in apple.
State Key Laboratory of Crop Biology, Tai-An, Shandong 271018, China; National Research Center for Apple Engineering and Technology, Tai-An, Shandong 271018, China; College of Horticulture Science and Engineering, Shandong Agricultural University, Tai-An, Shandong 271018, China.
Cheng
C
Zhao
College of Biological Science and Technology, Beijing Forestry University, Beijing 100083, China.
Ke
K
Mao
State Key Laboratory of Crop Biology, Tai-An, Shandong 271018, China; National Research Center for Apple Engineering and Technology, Tai-An, Shandong 271018, China; College of Horticulture Science and Engineering, Shandong Agricultural University, Tai-An, Shandong 271018, China.
Chun-Xiang
CX
You
State Key Laboratory of Crop Biology, Tai-An, Shandong 271018, China; National Research Center for Apple Engineering and Technology, Tai-An, Shandong 271018, China; College of Horticulture Science and Engineering, Shandong Agricultural University, Tai-An, Shandong 271018, China.
Xian-Yan
XY
Zhao
State Key Laboratory of Crop Biology, Tai-An, Shandong 271018, China; National Research Center for Apple Engineering and Technology, Tai-An, Shandong 271018, China; College of Horticulture Science and Engineering, Shandong Agricultural University, Tai-An, Shandong 271018, China.
Shu-Hui
SH
Wang
State Key Laboratory of Crop Biology, Tai-An, Shandong 271018, China; National Research Center for Apple Engineering and Technology, Tai-An, Shandong 271018, China; College of Horticulture Science and Engineering, Shandong Agricultural University, Tai-An, Shandong 271018, China. Electronic address: liyy0912@163.com.
Yuan-Yuan
YY
Li
State Key Laboratory of Crop Biology, Tai-An, Shandong 271018, China; National Research Center for Apple Engineering and Technology, Tai-An, Shandong 271018, China; College of Horticulture Science and Engineering, Shandong Agricultural University, Tai-An, Shandong 271018, China. Electronic address: haoyujin@sdau.edu.cn.
Yu-Jin
YJ
Hao
D020816:Amino Acid Motifs; D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000235:genetics* / Q000502:physiology / Q000528:radiation effects; D029681:Arabidopsis Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D002868:Chromosomal Proteins, Non-Histone / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D003001:Cloning, Molecular; D015870:Gene Expression; D017930:Genes, Reporter; D018546:Hypocotyl / Q000235:genetics / Q000502:physiology / Q000528:radiation effects; D027845:Malus / Q000235:genetics* / Q000502:physiology / Q000528:radiation effects; D008958:Models, Molecular; D009154:Mutation; D009928:Organ Specificity; D010802:Phylogeny; D010940:Plant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D030821:Plants, Genetically Modified; D036226:Seedlings / Q000235:genetics / Q000502:physiology / Q000528:radiation effects; D016415:Sequence Alignment; D017422:Sequence Analysis, DNA; D015398:Signal Transduction; D020798:Two-Hybrid System Techniques; D014466:Ultraviolet Rays
D029681:Arabidopsis Proteins; D002868:Chromosomal Proteins, Non-Histone; D010940:Plant Proteins; C525052:Uvr8 protein, Arabidopsis
Apple; Arabidopsis; Functional characterization; MdUVR8; Molecular cloning