**6.1 Inhibitory action on seedling growth**

Exogenous application of JA possibly shows inhibition of primary root growth, leaf expansion, and hypocotyl elongation which ultimately leads to inhibitory action in seedling growth [30]. InsP5 enhances the interaction of COI1 with JAZ9 and the inhibitory effect of JAs on root growth [31]. JA represses leaf expansion by inhibiting the activity of the mitotic cyclin CycB1;2 and cell division, rather than by affecting cell size. Transcription factor like MYC2 and its close homologs shows both positive and negative effects on hypocotyls in red/far-red light and blue light conditions; it works positively in inhibition of hypocotyl elongation in red/far-red light and negatively regulates the inhibition of hypocotyl elongation by blue light. ERF109 binds to and activates *anthranilate synthase Α1* (*ASA1*) and *YUCCA2 (*promoters of the auxin biosynthetic genes) and results in the promotion of lateral root formation in Arabidopsis [32].
