Light- and IAA-regulated ACC synthase gene ( PnACS) from Pharbitis nil and its possible role in IAA-mediated flower inhibition

• Published in: Journal of plant physiology 2009-01, Vol.166 (2), p.192-202
• Main Authors: Frankowski, Kamil, Kęsy, Jacek, Wojciechowski, Waldemar, Kopcewicz, Jan
• Format: Article
• Language: English
• Subjects: 1-aminocyclopropane-1-carboxylate synthase; ACC synthase; Amino Acid Sequence; amino acid sequences; Auxin; Base Sequence; complementary DNA; Cotyledon - drug effects; Cotyledon - enzymology; Cotyledon - genetics; Cotyledon - radiation effects; cotyledons; diurnal variation; DNA, Complementary - isolation & purification; Ethylene; Flowering; Flowers - drug effects; Flowers - enzymology; Flowers - radiation effects; Gene Expression Profiling; gene expression regulation; Gene Expression Regulation, Enzymologic - drug effects; Gene Expression Regulation, Enzymologic - radiation effects; Gene Expression Regulation, Plant - drug effects; Gene Expression Regulation, Plant - radiation effects; indole acetic acid; Indoleacetic Acids - pharmacology; Ipomoea nil; Ipomoea nil - drug effects; Ipomoea nil - enzymology; Ipomoea nil - genetics; Ipomoea nil - radiation effects; Light; Lyases - chemistry; Lyases - genetics; Lyases - metabolism; messenger RNA; molecular cloning; Molecular Sequence Data; nucleotide sequences; Organ Specificity - drug effects; Organ Specificity - radiation effects; Pharbitis nil; Pharbitis nil ( Ipomoea nil); Photoperiod; Phylogeny; RNA, Messenger - genetics; RNA, Messenger - metabolism; seedlings; Seedlings - drug effects; Seedlings - enzymology; Seedlings - genetics; Seedlings - radiation effects; tissue distribution
• ISSN: 0176-1617; 1618-1328
• DOI: 10.1016/j.jplph.2008.02.013

The light- and indole-3-acetic acid (IAA)-regulated 1-aminocyclopropane-1-carboxylic acid (ACC) synthase gene ( PnACS) from Pharbitis nil was isolated. Here, it was shown that the gene was expressed in cotyledons, petioles, hypocotyls, root and shoot apexes both in light- and dark-grown seedlings. The highest expression level of PnACS was found in the roots. IAA applied to the cotyledons of P. nil seedlings caused a clear increase of PnACS messenger accumulation in all the organs examined. In this case, the most IAA-responsive were the hypocotyls. Our studies revealed that the PnACS transcript level in the cotyledons exhibited diurnal oscillations under both long-day (LD) and short-day (SD) conditions. IAA applied at the beginning of inductive darkness caused a dramatic increase in the expression of PnACS, suggesting that the inhibitory effect of IAA on P. nil flowering may result from its stimulatory effect on ethylene production.