Blue light and NAA treatment significantly improve rooting on single leaf-bud cutting of Chrysanthemum via upregulated rooting-related genes

•Blue light application overcomes poor rooting in low positioned leaf-bud cuttings.•CmLBD1 was significantly increased at earlier root formation by BL.•Exogenous NAA prevents the necrosis of the stem around cut surface in RL.•Over expression of auxin related genes by FL seems no direct interaction with rooting. Single leaf-bud cutting has been attempted in an effort to produce multiple individuals; however, these cuttings produce individuals of irregular quality with different rooting abilities based on the cutting positions of the mother stem. We evaluated whether light and 1-naphthaleneacetic acid (NAA) treatment can improve root formation from relatively poor stem cuttings on single leaf-bud cuttings and which factor is more effective for rapid root formation. Blue (BL), red (RL), and fluorescent (FL) with/without NAA were independently applied to single leaf-bud cuttings. High-intensity BL together with NAA treatment efficiently induced adventitious root formation and improved root formation from poor stems. We also evaluated relative expression levels of seven kinds of rooting-related genes on cutting processes to define the critical light factor leading to rapid adventitious rooting. CmLBD1 was significantly upregulated after 5 day BL treatment and initiated rooting, whereas the expressions of other rooting-related genes were significantly increased by fluorescent light after 14 days cutting initiation.