Extraction methods for analysis of Citrus leaf proteins by two-dimensional gel electrophoresis

General procedures for the extraction of Citrus leaf proteins for analysis by two-dimensional electrophoresis (2-DE) were developed through the evaluation and modification of existing methods. Among the methods evaluated, the best results were obtained when Tris–HCl, KCl, and phenol extractions were followed by precipitation with organic solvents to purify and concentrate the samples. The utility of the Tris–HCl extraction method was demonstrated on the leaves of six genetically different Citrus varieties. The methods described are versatile and result in high resolution 2-DE gels of Citrus leaf proteins.