RAP2.6L mRNA Level in Oil Palm (Elaeis guineensis) Leaf, Inflorescence Explants and Calli Produced From Them

Abstract

The RAP2.6L is a member of the ERF (ethylene response factor) subfamily β‐4 of the ERF/APETALA2 transcription factor gene family. These preliminary studies seek to investigate the mRNA level of RAP2.6L gene in oil palm (Elaeis guineensis) leaf, inflorescence explants and the calli produced from them, with a view to understanding the molecular basis of direct and indirect organogenesis. Callus was induced and proliferated from non‐chlorophyllous leaf and immature inflorescence tissues using Murashige and Skoog medium. This was supplemented with different concentrations of auxins: 2,4‐D and NAA, ranging from 100‐120 mg/l and 170‐200 mg/l respectively. The times taken for callus induction, percentage callusing explants and weight of fresh callus after 20 weeks of culture initiation were recorded. Callus production was seen to vary in time of initial response and quantity produced for both 2,4‐D and NAA treatments. The leaf tissues yielded more callus in less time than the inflorescence tissues. Treatment 100mg/l 2,4‐D was effective in producing callus in 11 % of leaf explants, while 185 mg/l NAA was more effective in producing callus in 8 % of same. The level of RAP2.6L mRNA was measured with reverse transcription polymerase chain reaction (RT‐PCR). The results obtained indicated that there was no significant difference in the RAP2.6L mRNA level among the explants and associated calli, suggesting that both explants were equally amenable to indirect organogenesis.