title: Abscisic acid regulates gene expression in cortical fiber cells and silica cells of rice shoots.
abstract: Drought-induced growth arrest is a major cause of yield loss in crops and is mediated in part by abscisic acid (ABA). The aim of this study was to identify the cell types targeted by ABA during arrest. As transcription factors ABI3 and ABI5 are essential for ABA-induced growth arrest in Arabidopsis, blast was used to identify OsVP1 and OsABF1 as their structural orthologues in rice (Oryza sativa), and employed RNA in situ hybridization to reveal the cell types accumulating the corresponding transcripts in response to ABA. Exogenous ABA arrested the growth of leaves 1, 2 and 3 in young rice shoots and inhibited secondary cell-wall formation in sclerenchyma, including expression of the cellulose synthase gene OsCesA9. Transcripts for OsVP1, OsABF1 and of the putative target genes OsEm, OsLEA3 and WSI18, increased under ABA, accumulating principally in the cytosol of the major support cells (sclerenchymatous cortical fiber cells and epidermal silica cells) of slowly growing leaf 1. Rapidly growing immature tissues in leaves 2 and 3 accumulated OsABF1, OsEm and WSI18 transcripts in the nuclei of all cells, irrespective of ABA treatment. It is concluded that during arrest of leaf growth, ABA targets support cells in maturing tissues. Target cells in immature tissues remain to be identified.
authors.affiliation: Plant Breeding, Genetics and Biotechnology Division, International Rice Research Institute, DAPO Box 7777, Metro Manila, Philippines.|Department of Plant Breeding, Tarbiat Modares University, PO Box 14115-111, Tehran, Iran.
authors.forename: Zahra-Sadat
authors.initials: ZS
authors.lastname: Shobbar
authors.affiliation: Plant Breeding, Genetics and Biotechnology Division, International Rice Research Institute, DAPO Box 7777, Metro Manila, Philippines.
authors.forename: Rowena
authors.initials: R
authors.lastname: Oane
authors.affiliation: Plant Breeding, Genetics and Biotechnology Division, International Rice Research Institute, DAPO Box 7777, Metro Manila, Philippines.
authors.forename: Rico
authors.initials: R
authors.lastname: Gamuyao
authors.affiliation: Plant Breeding, Genetics and Biotechnology Division, International Rice Research Institute, DAPO Box 7777, Metro Manila, Philippines.
authors.forename: Justina
authors.initials: J
authors.lastname: De Palma
authors.affiliation: Department of Plant Breeding, Tarbiat Modares University, PO Box 14115-111, Tehran, Iran.|National Research Center for Genetic Engineering and Biotechnology, PO Box 14155-6343, Tehran, Iran.
authors.forename: Mohammad Ali
authors.initials: MA
authors.lastname: Malboobi
authors.affiliation: Department of Plant Breeding, Tarbiat Modares University, PO Box 14115-111, Tehran, Iran.
authors.forename: Ghasem
authors.initials: G
authors.lastname: Karimzadeh
authors.affiliation: Department of Plant Breeding, Tarbiat Modares University, PO Box 14115-111, Tehran, Iran.
authors.forename: Mokhtar Jalali
authors.initials: MJ
authors.lastname: Javaran
authors.affiliation: Plant Breeding, Genetics and Biotechnology Division, International Rice Research Institute, DAPO Box 7777, Metro Manila, Philippines.
authors.forename: John
authors.initials: J
authors.lastname: Bennett
mesh_terms: D000040:Abscisic Acid / Q000502:physiology*; D018506:Gene Expression Regulation, Plant; D012275:Oryza / Q000235:genetics / Q000254:growth & development* / Q000378:metabolism; D018520:Plant Shoots / Q000254:growth & development* / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D036226:Seedlings / Q000254:growth & development; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism
chemical_list: D014157:Transcription Factors; D000040:Abscisic Acid