Characterization of GaWRKY1, a cotton transcription factor that regulates the sesquiterpene synthase gene (+)-delta-cadinene synthase-A.
The cotton (+)-delta-cadinene synthase (CAD1), a sesquiterpene cyclase, catalyzes a branch-point step leading to biosynthesis of sesquiterpene phytoalexins, including gossypol. CAD1-A is a member of CAD1 gene family, and its promoter contains a W-box palindrome with two reversely oriented TGAC repeats, which are the proposed binding sites of WRKY transcription factors. We isolated several WRKY cDNAs from Gossypium arboreum. One of them, GaWRKY1, encodes a protein containing a single WRKY domain and a putative N-terminal Leu zipper. Similar to genes encoding enzymes of cotton sesquiterpene pathway, GaWRKY1 was down-regulated in a glandless cotton cultivar that contained much less gossypol. GaWRKY1 showed a temporal and spatial pattern of expression comparable to that of CAD1-A in various aerial organs examined, including sepal, stigma, anther, and developing seeds. In suspension cells, expression of both GaWRKY1 and CAD1-A genes and biosynthesis of sesquiterpene aldehydes were strongly induced by a fungal elicitor preparation and methyl jasmonate. GaWRKY1 interacted with the 3x W-box derived from CAD1-A promoter in yeast (Saccharomyces cerevisiae) one-hybrid system and in vitro. Furthermore, in transgenic Arabidopsis plants, overexpression of GaWRKY1 highly activated the CAD1-A promoter, and transient assay in tobacco (Nicotiana tabacum) leaves demonstrated that W-box was required for this activation. These results suggest that GaWRKY1 participates in regulation of sesquiterpene biosynthesis in cotton, and CAD1-A is a target gene of this transcription factor.
Xu
Yan-Hua
YH
National Key Laboratory of Plant Molecular Genetics, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200032, China.
Wang
Jia-Wei
JW
Wang
Shui
S
Wang
Jian-Ying
JY
Chen
Xiao-Ya
XY
D000085:Acetates / Q000494:pharmacology; D000595:Amino Acid Sequence; D019755:Carbon-Carbon Lyases / Q000235:genetics* / Q000378:metabolism; D003517:Cyclopentanes / Q000494:pharmacology; D018076:DNA, Complementary / Q000737:chemistry / Q000235:genetics; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism; D004789:Enzyme Activation / Q000187:drug effects; D018507:Gene Expression Regulation, Developmental; D015971:Gene Expression Regulation, Enzymologic; D018506:Gene Expression Regulation, Plant; D003368:Gossypium / Q000201:enzymology / Q000235:genetics* / Q000382:microbiology; D006072:Gossypol / Q000378:metabolism*; D006861:Hydrogen Peroxide / Q000494:pharmacology; D007113:Immunity, Innate / Q000235:genetics / Q000502:physiology; D007535:Isomerases / Q000235:genetics* / Q000378:metabolism; D008969:Molecular Sequence Data; D054883:Oxylipins; D010935:Plant Diseases / Q000235:genetics / Q000382:microbiology; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism; D020156:Salicylic Acid / Q000494:pharmacology; D017422:Sequence Analysis, DNA; D017386:Sequence Homology, Amino Acid; D014157:Transcription Factors / Q000235:genetics* / Q000378:metabolism; D020172:Verticillium / Q000254:growth & development
D000085:Acetates; D003517:Cyclopentanes; D018076:DNA, Complementary; D004268:DNA-Binding Proteins; D054883:Oxylipins; D010940:Plant Proteins; D014157:Transcription Factors; C072239:methyl jasmonate; D006861:Hydrogen Peroxide; D019755:Carbon-Carbon Lyases; C051130:trichodiene synthetase; D007535:Isomerases; C097608:delta-cadinene synthase; D006072:Gossypol; D020156:Salicylic Acid