title: A cotton fiber-preferential promoter, PGbEXPA2, is regulated by GA and ABA in Arabidopsis.
abstract: PGbEXPA2 (Promoter of GbEXPA2 ) was preferentially and strongly expressed during cotton fiber development, and the 461-bp PGbEXPA2 fragment was essential for responding to exogenous GA and ABA in Arabidopsis. Cotton fibers are highly elongated single-cell, unbranched and non-glandular seed trichomes. Previous studies have reported that the transcript level of GbEXPA2 is significantly up-regulated during fiber cell elongation, suggesting that GbEXPA2 has an important function in fiber development. In this study, the promoter of GbEXPA2 (839 bp) from the D(T) sub-genome was isolated from Gossypium barbadense 3-79. Consistent with the expression pattern of GbEXPA2, the promoter PGbEXPA2 was able to express GUS to high levels in elongating fibers, but not in the root, stem, or leaf. In Arabidopsis, GUS activity was only found in the rosette leaf trichomes and rosette leaf vascular tissue, indicating that the transcription factors which bind to PGbEXPA2 in the leaf trichomes of transgenic Arabidopsis were similar to those found in cotton fiber. A deletion analysis of PGbEXPA2 revealed that a 461-bp fragment was sufficient to drive GUS expression in cotton fibers and Arabidopsis rosette leaf trichomes. Exogenous phytohormonal treatments on transgenic Arabidopsis with different promoter lengths (P-839, P-705, P-588 and P-461) showed that GUS activity in Arabidopsis trichomes could be strongly up-regulated by GA and, in contrast, down-regulated by ABA.
authors.affiliation: National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan, 430070, Hubei, China.
authors.forename: Yang
authors.initials: Y
authors.lastname: Li
authors.forename: Lili
authors.initials: L
authors.lastname: Tu
authors.forename: Zhengxiu
authors.initials: Z
authors.lastname: Ye
authors.forename: Maojun
authors.initials: M
authors.lastname: Wang
authors.forename: Wenhui
authors.initials: W
authors.lastname: Gao
authors.forename: Xianlong
authors.initials: X
authors.lastname: Zhang
mesh_terms: D000040:Abscisic Acid / Q000494:pharmacology*; D017360:Arabidopsis / Q000235:genetics*; D020029:Base Pairing / Q000235:genetics; D015139:Blotting, Southern; D016000:Cluster Analysis; D032561:Cotton Fiber; D018506:Gene Expression Regulation, Plant / Q000187:drug effects; D017343:Genes, Plant; D005875:Gibberellins / Q000494:pharmacology*; D005966:Glucuronidase / Q000378:metabolism; D003368:Gossypium / Q000235:genetics; D009928:Organ Specificity / Q000187:drug effects / Q000235:genetics; D018515:Plant Leaves / Q000187:drug effects / Q000235:genetics; D010940:Plant Proteins / Q000235:genetics* / Q000378:metabolism; D030821:Plants, Genetically Modified; D011401:Promoter Regions, Genetic
chemical_list: D005875:Gibberellins; D010940:Plant Proteins; C095825:expansin protein, plant; D000040:Abscisic Acid; C007842:gibberellic acid; D005966:Glucuronidase