Expression profiling of cell cycle regulatory genes E2F and CDKA during early stages of zygotic embryo culture in coconut (Cocos nucifera L.)

Coconut (Cocos nucifera L.) is known to be highly recalcitrant to in vitro manipulations. The current study was conducted to comprehend the impact of different plant growth regulators (PGRs) on the early in vitro response of coconut embryos. The zygotic embryos were inoculated on Y3 media supplemented with four combinations of PGRs; first medium with 2,4-D (2 mg L⁻¹) and BA (5 mg L⁻¹); second medium with 2,4-D (2 mg L⁻¹), BA (5 mg L⁻¹) and GA3 (1.6 mg L⁻¹); third medium with GA3 (1.6 mg L⁻¹); fourth medium with TDZ (33 mg L⁻¹) and the basal Y3 medium as the control. Observations from in vitro culture study revealed that GA3 and TDZ had positive impact on the response of embryos. The expression profiling of cell cycle controlling genes, E2F (E2 promoter binding Factor) and CDKA (Cyclin Dependent Kinase A), during early response stages of coconut zygotic embryos was performed using qRT-PCR, keeping α- tubulin and 18S rRNA genes as endogenous control. In the media supplemented with GA3 alone, there was 245.5, 68.45 and 4.19-fold up regulation of E2F gene during 5, 10 and 20 DAI (days after inoculation) respectively when compared with the basal Y3 medium. The CDKA gene showed 4.23, 1.36 and 3.85-fold up regulation in TDZ supplemented media during 5, 10 and 20 DAI. However, at 10 DAI, the expression of CDKA was highest in GA3 medium with 19.82-fold up regulation. The PGRs GA3 and TDZ can therefore be used to overcome in vitro recalcitrance of coconut embryos during the early response stages.

Duke Scholars

Author Smita K Nair Surgery, Surgical Sciences