Comparison of Protein Profile and Peroxidases in Bush and Vine-type Tropical Pumpkin

Comparisons of total peroxidase activity and peroxidase isozymes as well as protein profiles among segregating, near-isogenic bush and vine phenotypes of pumpkin (Cucurbita moschata Duchesne) were investigated. Peroxidase activities of internode and leaf tissues of the bush plants were higher than those of respective vine tissues. Roots of bush plants, however, had a lower peroxidase activity than vine plants. In both bush and vine plants, peroxidase activities were lower in leaf tissues than in root and internode tissues. Electrophoretic comparisons revealed qualitative differences in peroxidase patterns in internodes between bush and vine plants. Moreover, qualitative differences between internode and root profiles were found between bush and vine plants in C. moschata. Inconclusion, the results of this reportrevealed that asingle gene conferring the bush phenotype inC. moschatamight affect the relative expression of peroxidase activity, peroxidase isozymes, and protein profiles in leaf, internode, and root tissues. Peroxidases (EC 1.11.1.7) have many physiological roles in several primary and secondary metabolic processes, such as scavenging of peroxide, participation in lignification, regula- tion of cell growth and differentiation, hormonal signaling, plant defense, indol-3-yl-acetic acid (IAA) catabolism, oxida- tion of toxic compounds, and ethylene biosynthesis (Campa, 1991). The plant cell wall is a very dynamic structure which controls both cell shape and cell elongation. Various enzymatic processes cleave and re-assemble the cell-wall constituents