Abstract:

Pepper cultivar HDA149 (Capsicum annuum L.) is resistant to Meloidogyne incognita, which is controlled by a single dominant gene Me3. To determine the type of WRKY genes and their expression characteristics during the incompatible interaction between HDA149 and Meloidogyne incognita, homology-based cloning and RT-PCR approaches were used in this study. Four new hot pepper WRKY genes were isolated from HDA149 after challenging inoculation with J2 root-knot nematode and the complete cDNAs of six WRKY genes i.e. WRKY-a, WRKY-b, WRKY-c, CaWRKY1, WRKY1 and CaWRKY2 were amplified. It was shown that the expression of WRKY-a and CaWRKY2 was induced by root-knot nematode. The CaWRKY1 gene expressed differently in various tissues of the plant, e.g. it expressed in roots and leaves but not in stems. Cluster analysis indicated WRKY-a, WRKY-c and CaWRKY2 proteins were clustered into the groupⅠ of WRKY protein, WRKY-b and CaWRKY1 proteins were classified as subgroup Ⅱc, whereas WRKY1 protein in subgroup Ⅱa. WRKY genes regulate HDA149 resistance to root knot nematode together.

Key words: hot pepper, WRKY transcription factor, gene cloning, cluster analysis