Expression analysis of sweetpotato NADPH oxidase-encoding Rboh genes in response to infection with the root-knot nematode Meloidogyne incognita

Sweetpotato ( Ipomoea batatas L.) is a globally important food crop that is susceptible to infestation with the root-knot nematode Meloidogyne incognita , which can cause substantial crop losses. Previous transcriptomic analysis of the roots of susceptible and resistant sweetpotato cultivars identified genes that were likely to contribute to protection against root-knot nematode. The identified genes included respiratory burst oxidase homolog ( Rboh ) genes, which encode NAPDH oxidase homologs in plants. In this study, the role of Rboh genes in sweetpotato defense responses during root-knot nematode infection was examined in susceptible and resistant cultivars. Comparison with Arabidopsis Rboh genes identified groups of sweetpotato genes orthologous to AtRboh B , E , F , and G . Of these, the group resembling AtrbohB contained the highest number of unigenes, nine, and these genes were highly responsive to nematode infection in sweetpotato roots. These results indicate that Rboh genes play roles in protecting sweetpotato roots against root-knot nematode infection.