title: ZmRFP1, the putative ortholog of SDIR1, encodes a RING-H2 E3 ubiquitin ligase and responds to drought stress in an ABA-dependent manner in maize.
abstract: Drought is one of the most important limiting factors in crop production. To identify genes required for the drought stress response in the cereal crop maize, a gene coding for RING-finger protein (ZmRFP1), which is highly responsive to PEG-induced drought stress, was isolated by mRNA differential display and rapid amplification of cDNA ends. The ZmRFP1 encodes a protein of 280 amino acids and contains a single C(3)H(2)C(3)-type RING motif in its C-terminal region. ZmRFP1 is an ortholog of Arabidopsis SDIR1 (salt- and drought-induced RING finger 1) (66% identity to AtSDIR1).The recombinant ZmRFP1 protein purified from Escherichia coli exhibited an in vitro E3 ubiquitin ligase activity. Real-time PCR analysis indicates that the transcript levels of ZmRFP1 were higher in aerial tissues including stems, leaves, tassels and immature ears, and were markedly up-regulated by drought stress, and exogenous ABA, but not by salt, heat and cold stresses. Transient expression of the green fluorescent protein (GFP)-ZmRFP1 fusion protein in onion cells revealed a plasma membrane localization of the protein. Further analysis of ZmRFP1 transcripts between an ABA-deficient transposon mutant viviparous14 (vp14) and its isogenic wild-type line W22 showed that ZmRFP1 transcript levels were induced significantly in the wild-type line under drought stress, but not in the mutant line VP14. These results indicate that ZmRFP1 responds to drought stress in an ABA-dependent way and is likely to function in the ubiquitin conjunction pathway. The ZmRFP1 might serve as a candidate gene in genetic improvement for drought tolerance engineering in cereal crop plants.
authors.affiliation: College of life science, Henan Agricultural University, Zhengzhou 450002, PR China. xiazl08@163.com
authors.forename: Zongliang
authors.initials: Z
authors.lastname: Xia
authors.forename: Quanjun
authors.initials: Q
authors.lastname: Liu
authors.forename: Jianyu
authors.initials: J
authors.lastname: Wu
authors.forename: Junqiang
authors.initials: J
authors.lastname: Ding
mesh_terms: D000040:Abscisic Acid / Q000378:metabolism*; D020816:Amino Acid Motifs; D000595:Amino Acid Sequence; D029681:Arabidopsis Proteins / Q000235:genetics; D003080:Cold Temperature; D055864:Droughts; D018506:Gene Expression Regulation, Plant; D049452:Green Fluorescent Proteins / Q000235:genetics / Q000378:metabolism; D006358:Hot Temperature; D008969:Molecular Sequence Data; D009154:Mutation; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism*; D030821:Plants, Genetically Modified; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D017386:Sequence Homology, Amino Acid; D013312:Stress, Physiological / Q000187:drug effects / Q000235:genetics*; D044767:Ubiquitin-Protein Ligases / Q000235:genetics / Q000378:metabolism*; D003313:Zea mays / Q000502:physiology*
chemical_list: D029681:Arabidopsis Proteins; D010940:Plant Proteins; D011993:Recombinant Fusion Proteins; D049452:Green Fluorescent Proteins; D000040:Abscisic Acid; C523446:SDIR1 protein, Arabidopsis; D044767:Ubiquitin-Protein Ligases