title: Water-stress-induced inhibition of α-tubulin gene expression during growth, and its implications for reproductive success in rice.
abstract: A drought-suppressed cDNA (RiP-3), encoding a putative α-tubulin protein was isolated from rice panicle at pollen-mother-cell meiosis stage. Analysis of its deduced amino acid sequence showed all the typical structural motifs for plant α-tubulins. The expression of α-tubulin transcripts was observed in all the reproductive organs of rice panicle, and in 5- or 15-day old seedlings, but not in mature leaves. Expression levels were positively correlated with the regions and periods of high growth, and the transcript level declined in parallel with drought-induced reduction in growth rates in all tissues examined. Immunoblot analysis of proteins separated by SDS-PAGE with anti-α-tubulin monoclonal antibody showed that the level of protein paralleled the changes in the transcript abundance in these organs. In situ immunolocalization of the α-tubulin protein in sections of the basal part of 5-day old seedlings showed that the highest levels of the protein were associated with the fastest growing leaf whorls, and the protein level declined upon a brief episode of water stress. Given the known critical role of tubulin in cell division and elongation, the results indicate that the expression of α-tubulin gene may be part of the events that suppress panicle elongation during water deficit, which is in turn a suspected cause of male reproductive failure and yield reduction in rice.
authors.affiliation: Institut de recherche en biologie végétale, Université de Montréal, Montreal, QC H1X 2B2, Canada. Electronic address: inder.sheoran@utoronto.ca.
authors.forename: Inder S
authors.initials: IS
authors.lastname: Sheoran
authors.affiliation: Institut de recherche en biologie végétale, Université de Montréal, Montreal, QC H1X 2B2, Canada. Electronic address: priyum.koonjul@valeosec.com.
authors.forename: Priyum
authors.initials: P
authors.lastname: Koonjul
authors.affiliation: Institut de recherche en biologie végétale, Université de Montréal, Montreal, QC H1X 2B2, Canada. Electronic address: jihad.attieh@balamand.edu.lb.
authors.forename: Jihad
authors.initials: J
authors.lastname: Attieh
authors.affiliation: Institut de recherche en biologie végétale, Université de Montréal, Montreal, QC H1X 2B2, Canada. Electronic address: deep.saini@utoronto.ca.
authors.forename: Hargurdeep S
authors.initials: HS
authors.lastname: Saini
mesh_terms: D018506:Gene Expression Regulation, Plant / Q000235:genetics / Q000502:physiology; D012275:Oryza / Q000378:metabolism* / Q000502:physiology*; D012098:Reproduction; D014404:Tubulin / Q000235:genetics / Q000378:metabolism*
chemical_list: D014404:Tubulin
keywords: Growth; Oryza sativa; Reproduction; Tubulin; Water stress