Auxin increases the InJMT expression and the level of JAMe – inhibitor of flower induction in Ipomoea nil

Abstract

Interactions among jasmonates and auxin in the photoperiodic flower induction of a short-day plant <em>Ipomoea nil</em> were examined. Therefore, we measured changes in jasmonic acid (JA) and jasmonic acid methyl ester (JAMe) levels in the cotyledons of <em>I. nil</em> during the inductive night, as well as the effects of indole-3-acetic acid (IAA) on their content. We noticed an interesting result, that IAA applied on the cotyledons of <em>I. nil</em> is an effective stimulator of JAMe production in seedlings cultivated under inductive night conditions. IAA treatment also significantly increased the transcriptional activity of <em>InJMT</em> (<em>JASMONIC ACID CARBOXYL METHYLTRANSFERASE</em>), while did not affect the expression of JA biosynthesis genes (lipoxyganease, allene oxide synthase, 12-oxophytodienoate reductase). These data, as well as the results of our previous research, suggest that exogenous IAA participates in <em>I. nil</em> flower induction process by stimulating <em>InJMT</em> expression and, as a consequence of that, enhancing the level of JAMe, a flowering inhibitor.