The Arabidopsis mutant alh1 illustrates a cross talk between ethylene and auxin

Filip Vandenbussche, Jan Smalle, Jie Le, Nelson José Madeira Saibo, Annelies De Paepe, Laury Chaerle, Olaf Tietz, Raphael Smets, Lucas J.J. Laarhoven, Frans J.M. Harren, Harry Van Onckelen, Klaus Palme, Jean Pierre Verbelen, Dominique Van Der Straeten

Research output: Contribution to journalArticlepeer-review

83 Scopus citations

Abstract

Ethylene or its precursor 1-aminocyclopropane-1-carboxylic acid (ACC) can stimulate hypocotyl elongation in light-grown Arabidopsis seedlings. A mutant, designated ACC-related long hypocotyl 1 (alh1), that displayed a long hypocotyl in the light in the absence of the hormone was characterized. Etiolated alh1 seedlings overproduced ethylene and had an exaggerated apical hook and a thicker hypocotyl, although no difference in hypocotyl length was observed when compared with wild type. Alh1 plants were less sensitive to ethylene, as reflected by reduction of ACC-mediated inhibition of hypocotyl growth in the dark and delay in flowering and leaf senescence. Alh1 also had an altered response to auxin, whereas auxin levels in whole alh1 seedlings remained unaffected. In contrast to wild type, alh1 seedlings showed a limited hypocotyl elongation when treated with indole-3-acetic acid. Alh1 roots had a faster response to gravity. Furthermore, the hypocotyl elongation of alh1 and of ACC-treated wild type was reverted by auxin transport inhibitors. In addition, auxin up-regulated genes were ectopically expressed in hypocotyls upon ACC treatment, suggesting that the ethylene response is mediated by auxins. Together, these data indicate that alh1 is altered in the cross talk between ethylene and auxins, probably at the level of auxin transport.

Original languageEnglish
Pages (from-to)1228-1238
Number of pages11
JournalPlant Physiology
Volume131
Issue number3
DOIs
StatePublished - Mar 1 2003

ASJC Scopus subject areas

  • Physiology
  • Genetics
  • Plant Science

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