Expression analysis of sweetpotato cinnamyl alcohol dehydrogenase genes in response to infection with the root-knot nematode Meloidogyne incognita

Abstract

Sweetpotato (Ipomoea batatas L.) is a globally important food crop that is susceptible to infestation with the root-knot nematode, Meloidogyne incognita, which causes substantial crop losses. Previous transcriptomic analysis of the roots of susceptible and resistant sweetpotato cultivars identified genes that are likely to contribute to protection against root-knot nematode. The identified genes included cinnamyl alcohol dehydrogenase (CAD), which are related to monolignol biosynthesis in plants. In this study, the role of CAD genes in sweetpotato defense responses to root-knot nematode infection was examined in susceptible and resistant cultivars. Comparison with Arabidopsis thaliana CAD genes identified groups of sweetpotato genes orthologous to AtCAD1-AtCAD9. Genes of the two major sweetpotato CAD groups contained the highest number of unigenes that were highly responsive to nematode infection in sweetpotato roots. These results indicate that CAD genes play roles in protecting sweetpotato roots against root-knot nematode infection.