Spatial and Temporal Expression of Mutations for High Oleic Acid and Low Linolenic Acid Concentration in Ethiopian Mustard

Abstract

The development of Ethiopian mustard (Brassica carinata A. Braun) germplasm with high concentration of oleic acid and low concentration of linolenic add in its seed oil is an important breeding objective in this crop. The mutant AB-1, with high oleic acid and low linolenic acid concentration, and the mutant AB-4, with very low linolenic add concentration have recently been developed. In both cases, mutations are expressed at the seed oil level, but their level of expression in other plant tissues has not been studied. The objective of the present research was to monitor the expression of altered fatty acid profiles in AB-1 and AB-4 in different plant tissues and stages of seed development and germination. Plants of AB-1 expressed the high oleic acid trait in pollen, roots, and leaves and the low linolenic add trait in pollen and roots. Plants of the AB-4 mutant expressed the low linolenic add trait in pollen, roots, and leaves. The high oleic acid trait of AB-1 was expressed during the whole seed developing period, and also in 10-d-old cotyledons. The low linolenic acid trait of AB-4 was expressed during seed development and also from 0 to 8 d after germination. The expression of mutations for high oleic add and low linolenic acid in Ethiopian mustard mutants AB-1 and AB-4 in plant tissues other than seeds may have important breeding implications. Comparison of these results with previous studies on Brassica napus L. and Arabidopsis mutants suggested that AB-1 might show altered activity at both FAD2 and FAD3 microsomal desaturases, whereas AB-4 might show reduced activity at FAD3 level.