Development of an Isoelectric Focusing Technique for Characterising Isoenzyme Variability in Aphid Taxa

Abstract

An isoelectric focusing (IEF) method was developed for characterising differences in isooenzyme banding patterns in aphids. In this study, 18 enzyme systems namely adenylate kinase (AK); alkaline phosphatase (ALK-P) and acid phosphatase (ACID-P); -amylase ( -AMY); esterase's (EST); glucose-6-phosphate dehydrogenase (G-6-P-DeH); glutamate oxaloacetate transaminase (GOT); -glycerophosphate dehydrogenase ( -GPD); hexokinase (HK); leucine-alanine peptidase (LeAP); malate dehydrogenase (MTDH); malic enzyme (ME); malic enzyme dehydrogenase (MDH); peptidase P (PEP-P); peroxidase (POD); phosphoglucomutase (PGM); sorbitol dehydrogenase (SOD) and tetrazolium oxidase (TOD) were screened in an attempt to identify isoenzymes that might be useful in distinguishing between various aphid taxa at or above the species level or within the populations of single species. In this study the enzymes found to be most effective in distinguishing three morphologically distinct (but not critically identified) species of aphids collected from tobacco, cabbage and lemon plants were ACID-P, EST and GOT, while the remaining enzymes found to have limited discriminating power. The method developed in this study offers a cheap, sensitive and rapid technique for detecting expresed genmetic differences between single aphic individuals.


Transactions of the Zimbabwe Scientific Association Vol.74 2000: 1-5