Peroxidase isozyme variants as genetic markers for early evaluation of Fe-efficiency and Fe-nutritional status in maize lines

Abstract

The Fe-efficient maize ( Zea mays L.) cultivar Alice, the Fe-inefficient mutant yellow-stripe ( ys1), and six additional local inbred lines were grown in a growth chamber at 60% relative humidity and 16 h 25°C, 8 h 22°C day–night regime, in nutrient solution with varied Fe supply (+Fe=0.1 mM) or (−Fe=0.01 mM) supplied as Fe(III)–EDTA. The study aimed to establish a genetic assay system for early evaluation of Fe-efficiency and Fe-nutritional status based on peroxidase isozyme variation in roots of maize lines. The wild-type peroxidase isozyme patterns revealed an extra band (C3) not present in the mutant patterns. Inbreds 51, 122, 126, and 137 had peroxidase isozymes similar to the Fe-efficient Alice, while inbreds 112 and 144 had nearly the same pattern as the Fe-inefficient mutant ys1. Sufficient Fe supply did not alter the isoperoxidase patterns of the ys1, but had significant effect on the activity of the (C3) band of the Fe-efficient Alice. On the other hand, the activity of the (C3) band for the inbreds 51, 122, 126 and 137 responded clearly to the sufficient level of iron in the media similar to the response of Alice, while inbreds 112 and 144 did not show any changes in C3 either in sufficient or deficient Fe supply, similar to ys1. The results indicate that the Fe-efficient maize lines may have an additional cathodal (C3) band of the root isoperoxidase and that changes in the activity of the band can reflect the Fe-nutritional status of maize lines.