Abscisic acid regulates gene expression in cortical fiber cells and silica cells of rice shoots.
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.
Shobbar
Zahra-Sadat
ZS
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.
Oane
Rowena
R
Plant Breeding, Genetics and Biotechnology Division, International Rice Research Institute, DAPO Box 7777, Metro Manila, Philippines.
Gamuyao
Rico
R
Plant Breeding, Genetics and Biotechnology Division, International Rice Research Institute, DAPO Box 7777, Metro Manila, Philippines.
De Palma
Justina
J
Plant Breeding, Genetics and Biotechnology Division, International Rice Research Institute, DAPO Box 7777, Metro Manila, Philippines.
Malboobi
Mohammad Ali
MA
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.
Karimzadeh
Ghasem
G
Department of Plant Breeding, Tarbiat Modares University, PO Box 14115-111, Tehran, Iran.
Javaran
Mokhtar Jalali
MJ
Department of Plant Breeding, Tarbiat Modares University, PO Box 14115-111, Tehran, Iran.
Bennett
John
J
Plant Breeding, Genetics and Biotechnology Division, International Rice Research Institute, DAPO Box 7777, Metro Manila, Philippines.
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
D014157:Transcription Factors; D000040:Abscisic Acid