Molecular analysis of ARF1 expression profiles during development of physic nut (Jatropha curcas L.)

A cDNA clone designated arf1 was isolated from a physic nut (Jatropha curcas L.) endosperm cDNA library which encodes a small GTP-binding protein and has significant homology to ADP-ribosylation factors (ARF) in plants, animals and microbes. The cDNA contains an open reading frame that encodes a polypeptide of 181 amino acids with a calculated molecular mass of 20.7 kDa. The deduced amino acid sequence showed high homology to known ARFs from other organisms. The products of the arf1 obtained by overexpression in E. coli revealed the specific binding activity toward GTP. The expression of arf1 was observed in flowers, roots, stems and leaves as analyzed by RT-PCR, and its transcriptional level was highest in flowers. In particular, the accumulation of arf1 transcripts was different under various environmental stresses in seedlings. The results suggest that arf1 plays distinct physiological roles in Jatropha curcas cells.