ABI3 plays a role in de-novo root regeneration from Arabidopsis thaliana callus cells

Developmental plasticity and the ability to regenerate organs during the life cycle are a signature feature of plant system.De novoorganogenesis is a common mode of plant regeneration and may occur directly from the explant or indirectly via callus formation. It is now evident that callus formation occurs through the root development pathway. In fact, callus cells behave like a group of root primordium cells that are under the control of exogenous auxin. Presence or absence of auxin decides the subsequent fate of these cells. While in presence of external supplementation of auxin they are maintained as root primordia cells, absence of exogenous auxin induces the callus cells into patterning, differentiation and finally root emergence. Here we show that in absence of functional ABI3, a prominent member of the B3 superfamily of transcription factors, root regeneration is compromised in Arabidopsis callus cells. In culture medium free of any exogenous hormone supplementation, while adventitious root emergence and growth was prominently observed in wild type cells, no such features were observed inabi3-6cells. Expression of auxin-responsiveAUX1andGH3genes was significantly reduced inabi3-6cells, indicating that auxin levels or distribution may be altered in absence of ABI3.