you could try looking at another common protein gene in both human and plant and if the 2 proteins appear to use the same codons then use human to design 2 pcr primers .If these work for normal pcr then they  should have a good chance of working with RACE

Hi

I can suggest one alternative approach. You can download as many sequences as available for the species of interest from the databases and generate a custom codon usage/preference table for your problem. It is feasible. 

Otherwise if your organism is a eukaryote, you can utilize a oligo-dT primer containing a  specific sequence (to serve as a primer later in PCR) and an internal primer designed in a conserved region (align sequences to identify such region). This can be used for 3'-RACE to deduce the sequence of the gene/cDNA

Thanks Ajay

Thanks Paul and Artur