Analysis of the proteome of red and green leaf phenotypes of 'Bon Rouge' pear trees \trus communrls L. by 2-dimensional gel electrophoresis

Abstract

The 'Bon Rouge' pear is a red pear cultivar derived from a rare, spontaneous bud mutation which occurred on the green pear 'William's Bon Chretien' (Bartlett). 'Bon Rouge' pear cultivar was observed to be reverting back to its original phenotypic green colour. To study the cellular changes occurring within the cells both the mutated red phenotype and the wild type green phenotype of 'Bon Rouge' were investigated using proteomics approach. The proteins from the tissues of interest were precipitated in the presence of l0o/o TCA and solubilized in urea/thiourea lysis buffer. The proteins were separated onl2Yo SDS-PAGE and2D PAGE in order to compare their protein expression profiles. The results from SDS-PAGE and 2D PAGE profiles show an elevated level of 53 kDa protein in green pears which was either absent or less expressed in red phenotype and this protein appears to be the only differentiating factor between the red and green 'Bon Rouge' phenotypes. This protein was subsequently identified by the MALDI-TOFMS to be large subunit of RuBisCO. Expression proteomics is a preferred method due to its reproducibility and it has a potential to provide direct identification of cultivars related proteins. Additionally, proteomics approaches could help the fruit crop gtowers andbreeders, to select and determine types of different cultivars at various growth stages.