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

Interactions among jasmonates and auxin in the photoperiodic flower induction of a short-day plant Ipomoea nil were examined. Therefore, we measured changes in jasmonic acid (JA) and jasmonic acid methyl ester (JAMe) levels in the cotyledons of I. nil 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 I. nil is an effective stimulator of JAMe production in seedlings cultivated under inductive night conditions. IAA treatment also significantly increased the transcriptional activity of InJMT (JASMONIC ACID CARBOXYL METHYLTRANSFERASE), 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 I. nil flower induction process by stimulating InJMT expression and, as a consequence of that, enhancing the level of JAMe, a flowering inhibitor.