Differential alcohol dehydrogenase and malate dehydrogenase isozyme expression in long-term callus tissue cultures of Cereus peruvianus (Cactaceae).

Abstract

Alcohol dehydrogenase (ADH) and mitochondrial malate dehydrogenase (mMDH) isozymes were tested as markers to study the effect of a high kinetin concentration on isozyme phenotypes and on the development of Cereus peruvianus callus tissue culture. Three-year-old callus tissues were used as samples. Callus tissue samples grown on 4.0 mg/L 2,4-dichlorophenoxyacetic acid (2,4-D) and on 4.0 and 8.0 mg/L N-(2-furanylmethyl)-1H-purine-6 amine (kinetin) were cut and transferred to fresh medium containing 4.0 mg/L 2,4-D and 4.0, 8.0, 16.0, and 32 mg/L kinetin combinations. The pattern of changes observed in the ADH and mMDH isozymes as well as the growth of callus tissues was independent of the concentrations tested. The various ADH and mMDH isozymes seem to be products of differential association of subunits of the two Adh and two mMdh genes. Both genes are active throughout callus tissue development; however, gene expression changed with various callus culture condictions. This study addresses how long-term callus culture condictions affect constitutive and differential gene expression of the Adh and mMdh genes in C. peruvianus.