Lateral Organ Boundaries Domain 19 (LBD19) negative regulate callus formation in Arabidopsis

Callus is a remarkable regeneration tissue. The genes correlated with root development can be involved in regulating callus development in higher plants. Several Lateral Organ Boundaries Domain ( LBD ) transcription factors are known as the key regulators in callus induction, and they also participate in the development of lateral root. Here we took a systemic analysis approach to investigate the expression pattern of many LBD family members during callus induction on CIM medium. We found that most of the LBD members were upregulated on CIM medium but LBD19 was different from other family members showing increased expression at early stage but decreased expression later on. We were unable to obtain the loss of function mutant of lbd19 plant, so we generated the overexpression transgenic lines of LBD19 . The overexpression of LBD19 caused obvious phenotypic changes in vegetative development and suppressed callus formation. The quantitative RT-PCR analysis results revealed that the expression of most genes that promote callus formation were down-regulated in callus of oeLBD19 . These findings suggest that LBD19 may plays an important function in coordinating callus formation in Arabidopsis along with other LBD members.