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Abscisic acid regulates gene expression in cortical fiber cells and silica cells of rice shoots

Published by:
Publication date
31/03/2008
Language:
English
Type of Publication:
Articles & Journals
Focus Region:
Global
Focus Topic:
Agricultural Value Chains / Agri-Businesses
Type of Risk:
Biological & environmental
Commodity:
Crops
Source
http://dx.doi.org/10.1111/j.1469-8137.2007.02365.x
Author
Shobbar, Z.S.; Oane, R.; Gamuyao, R.; De Palma, J.; Malboobi, M.A.; Karimzadeh, G.; Javaran, M.J.; Bennett, J.

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.