Three Rca genes from O. australiensis were transformed into rice, the almost identical variants Rca-β and Rca-α and a 5 amino acid truncated version of Rca-β, all known to be of similar thermostability. As such, we treated the various events from the three transformations all as lines expressing an equally thermostable Rca-Oa product, with the critical difference being the abundance of there combinant protein observed for eac hline. There lative abundance of Rca-OaasapercentageofthetotalRca content in planta were 9.0±0.01, 15.0±0.02, and 19.3±0.02 for the Rca-α, Rca-β, and Rca-β truncated lines, respectively, which we henceforth refer to as Rca-Oa-9, Rca-Oa-15, and RcaOa-19, with the numbers referring to the percentage content of there combinant protein. A similar patternin gene expression of O.australiensis Rca to that of the protein abundance was observed