title: The transcription factors MS188 and AMS form a complex to activate the expression of CYP703A2 for sporopollenin biosynthesis in Arabidopsis thaliana.
abstract: The sexine layer of pollen grain is mainly composed of sporopollenins. The sporophytic secretory tapetum is required for the biosynthesis of sporopollenin. Although several enzymes involved in sporopollenin biosynthesis have been reported, the regulatory mechanism of these enzymes in tapetal layer remains elusive. ABORTED MICROSPORES (AMS) and MALE STERILE 188/MYB103/MYB80 (MS188/MYB103/MYB80) are two tapetal cell-specific transcription factors required for pollen wall formation. AMS functions upstream of MS188. Here we report that AMS and MS188 target the CYP703A2 gene, which is involved in sporopollenin biosynthesis. We found that AMS and MS188 were localized in tapetum while CYP703A2 was localized in both tapetum and locule. Chromatin immunoprecipitation (ChIP) showed that MS188 directly bound to the promoter of CYP703A2 and luciferase-inducible assay showed that MS188 activated the expression of CYP703A2. Yeast two-hybrid and electrophoretic mobility shift assays (EMSAs) further demonstrated that MS188 complexed with AMS. The expression of CYP703A2 could be partially restored by the elevated levels of MS188 in the ams mutant. Therefore, our data reveal that MS188 coordinates with AMS to activate CYP703A2 in sporopollenin biosynthesis of plant tapetum.
authors.affiliation: College of Life and Environment Sciences, Shanghai Normal University, 100 Guilin Road, Shanghai, 200234, China.
authors.forename: Shuang-Xi
authors.initials: SX
authors.lastname: Xiong
authors.affiliation: College of Life and Environment Sciences, Shanghai Normal University, 100 Guilin Road, Shanghai, 200234, China.
authors.forename: Jie-Yang
authors.initials: JY
authors.lastname: Lu
authors.affiliation: College of Life and Environment Sciences, Shanghai Normal University, 100 Guilin Road, Shanghai, 200234, China.
authors.forename: Yue
authors.initials: Y
authors.lastname: Lou
authors.affiliation: College of Life and Environment Sciences, Shanghai Normal University, 100 Guilin Road, Shanghai, 200234, China.
authors.forename: Xiao-Dong
authors.initials: XD
authors.lastname: Teng
authors.affiliation: College of Life and Environment Sciences, Shanghai Normal University, 100 Guilin Road, Shanghai, 200234, China.
authors.forename: Jing-Nan
authors.initials: JN
authors.lastname: Gu
authors.affiliation: College of Life and Environment Sciences, Shanghai Normal University, 100 Guilin Road, Shanghai, 200234, China.
authors.forename: Cheng
authors.initials: C
authors.lastname: Zhang
authors.affiliation: College of Life and Environment Sciences, Shanghai Normal University, 100 Guilin Road, Shanghai, 200234, China.
authors.forename: Qiang-Sheng
authors.initials: QS
authors.lastname: Shi
authors.affiliation: College of Life and Environment Sciences, Shanghai Normal University, 100 Guilin Road, Shanghai, 200234, China.
authors.forename: Zhong-Nan
authors.initials: ZN
authors.lastname: Yang
authors.affiliation: College of Life and Environment Sciences, Shanghai Normal University, 100 Guilin Road, Shanghai, 200234, China.
authors.forename: Jun
authors.initials: J
authors.lastname: Zhu
mesh_terms: D017360:Arabidopsis / Q000235:genetics / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D001704:Biopolymers / Q000096:biosynthesis*; D002338:Carotenoids / Q000096:biosynthesis*; D003577:Cytochrome P-450 Enzyme System / Q000235:genetics / Q000378:metabolism; D035264:Flowers / Q000235:genetics / Q000378:metabolism; D018506:Gene Expression Regulation, Plant / Q000235:genetics / Q000502:physiology; D011058:Pollen / Q000235:genetics / Q000378:metabolism; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*
chemical_list: D029681:Arabidopsis Proteins; D001704:Biopolymers; D014157:Transcription Factors; C009800:sporopollenin; D002338:Carotenoids; D003577:Cytochrome P-450 Enzyme System; C523532:cytochrome P-450 703A2, Arabidopsis
keywords: 
  Arabidopsis thaliana
  ; anther; pollen wall; tapetal cells; transcriptional regulation