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

Abstract

Developmental plasticity and the ability to regenerate organs during the life cycle are a signature feature of plant system. De novo organogenesis 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 in abi3-6 cells. Expression of auxin-responsive AUX1 and GH3 genes was significantly reduced in abi3-6 cells, indicating that auxin levels or distribution may be altered in absence of ABI3.

The epigenetic regulator ULTRAPETALA1 suppresses de novo root regeneration from Arabidopsis leaf explants

“…ABI3 , which is a direct target of ULT1, 16 is known to play an essential role in DNRR. 18 To test whether increased expression of ABI3 could promote adventitious root formation in ult1-3 mutants, we performed a comparative expression analysis in leaf explants 30 min after detachment. Although the expression of ABI3 was more variable in ult1-3 mutants, ABI3 mRNA levels were not significantly different from wild-type ( Figure 1e ), and therefore, ABI3 is likely not responsible for the increased rooting rates in ult1-3 .…”

“… 16 A recent study showed that ABI3 plays a role in DNRR from Arabidopsis callus cells. 18 We therefore address here the question whether ULT1 is also involved in root regeneration.…”

LEAFY COTYLEDONs: Connecting different stages of plant development

“…During the transition from juvenile to adult stage, plants are accompanied by multiple physiological and biochemical metabolic processes, such as biomass, reproductive capacity, resistance to pests and diseases, stress resistance, and plant architecture ( Chuck et al, 2011 ; Huang et al, 2015b ; Tang et al, 2017 ; Sengupta and Nag Chaudhuri, 2020 ). Previous studies have shown that LEAFY COTYLEDONs play an important role in regulating plant stage transitions.…”

Genetic and Molecular Control of Somatic Embryogenesis

“…ABI3 is essential for the emergence of roots from callus after induction of organogenesis. The abi3 -6 mutant does not show any regeneration after passing from a hormone-rich to a hormone-free medium [ 67 ]. Nevertheless, the overexpression of ABI3 does not induce somatic embryogenesis [ 68 , 69 ].…”