AtSWEET1 negatively regulates plant susceptibility to root-knot nematode disease.

The root-knot nematode is a pathogenic pest that causes severe economic loss to agricultural production by forming a parasitic relationship with its hosts. During the development of in the host plant roots, giant cells are formed as a nutrient sink. However, the roles of sugar transporters during the giant cells gain sugar from the plant cells are needed to improve. Meanwhile, the eventual function of sugars will eventually be exported transporters (SWEETs) in nematode-plant interactions remains unclear. In this study, the expression patterns of were examined by inoculation with at 3 days post inoculation (dpi) (penetration stage) and 18 dpi (developing stage). We found that few responded sensitively to inoculation, with the highest induction of (AT1G21460), a glucose transporter gene. Histological analyses indicated that the β-glucuronidase () and green fluorescent protein () signals were observed specifically in the galls of AtSWEET1-GUS and AtSWEET1-GFP transgenic plant roots, suggesting that was induced specifically in the galls. Genetic studies have shown that parasitism of was significantly affected in compared to wild-type and complementation plants. In addition, parasitism of was significantly affected in but not in and , expression of which was induced by inoculation with . Taken together, these data prove that SWEETs play important roles in plant and nematode interactions.