TITLE:
Cloning and Characterization of Eukaryotic Translation Initiation Factor 4E (eIF4E) Gene Family in Ipomoea batatas L. (Lam) for Understanding Hexaploid Sweetpotato-Virus Interactions
AUTHORS:
Adrianne P. A. Brown, Marceline Egnin, Foaziatu Bukari, Osagie Idehen, Inocent Ritte, Desmond Mortley, Gregory Bernard, Deloris Alexander, Conrad Bonsi
KEYWORDS:
Ipomoea batatas, Eukaryotic Translation Initiation Factors, eIF4E, CBP, eIF(iso)4E, Sweetpotato Viral Diseases
JOURNAL NAME:
American Journal of Molecular Biology,
Vol.12 No.4,
October
31,
2022
ABSTRACT: Characterization
of genes related to sweetpotato viral
disease resistance is critical for understanding plant-pathogen interactions,
especially with feathery mottle virus infection. For example, genes encoding
eukaryotic translation initiation factor (eIF)4E,
its isoforms, eIF(iso)4E,
and the cap-binding protein (CBP) in plants, have been implicated in
viral infections aside from their importance in protein synthesis. Full-length
cDNA encoding these putative eIF targets from susceptible/resistant and unknown
hexaploid sweetpotato (Ipomoea batatas L. Lam) were amplified based on
primers designed from the diploid wild-type relative Ipomoea trifida consensus sequences, and designated IbeIF4E, IbeIF(iso)4E and IbCBP.
Comparative analyses following direct-sequencing of PCR-amplified cDNAs versus
the cloned cDNA sequences identified multiple homeoalleles: one to four IbeIF4E, two to three IbeIF(iso)4E, and two IbCBP within all cultivars tested. Open reading frames were in the length of 696 bp IbeIF4E, 606 bp IbeIF(iso)4E,
and 675 bp IbCBP. The encoded single polypeptide lengths were 232, 202,
and 225 amino acids for IbeIF4E, IbeIF(iso)4E, and IbCBP,
with a calculated protein molecular mass of 26 kDa, 22.8 kDa, and 25.8 kDa,
while their theoretical isoelectric points were 5.1, 5.57, and 6.6,
respectively. Although the homeoalleles had similar sequence lengths, single
nucleotide polymorphisms and multi-allelic variations were detected within the
coding sequences. The multi-sequence alignment performed revealed a 66.9% - 96.7%
sequence similarity between the predicted amino acid sequences obtained from
the homeoalleles and closely related species. Furthermore, phylogenetic
analysis revealed ancestral relationships between the eIF4E homeoalleles and
other species. The outcome herein on the eIF4E superfamily and its correlation
in sequence variations suggest opportunities to decipher the role of eIF4E in
hexaploid sweetpotato feathery mottle virus infection.