Phytoparasitic nematodes secrete an array of effector
proteins to modify selected recipient plant cells into elaborate and essential feeding sites. The biological function of the novel 30C02 effector
protein of the soybean
cyst nematode, Heterodera glycines, was studied using Arabidopsis thaliana as host and the beet
cyst nematode, Heterodera schachtii, which contains a homologue of the 30C02 gene. Expression of Hg30C02 in Arabidopsis did not affect plant growth and development but increased plant susceptibility to
infection by H. schachtii. The 30C02
protein interacted with a specific (AT4G16260) host plant β-1,3-endoglucanase in both yeast and plant cells, possibly to interfere with its role as a plant pathogenesis-related
protein. Interestingly, the peak expression of 30C02 in the nematode and peak expression of At4g16260 in plant roots coincided at around 3-5 d after root
infection by the nematode, after which the relative expression of At4g16260 declined significantly. An Arabidopsis At4g16260
T-DNA mutant showed increased susceptibility to
cyst nematode infection, and plants that overexpressed At4g16260 were reduced in nematode susceptibility, suggesting a potential role of host β-1,3-endoglucanase in the defence response against H. schachtii
infection. Arabidopsis plants that expressed dsRNA and its processed
small interfering RNA complementary to the Hg30C02 sequence were not phenotypically different from non-transformed plants, but they exhibited a strong RNA interference-mediated resistance to
infection by H. schachtii. The collective results suggest that, as with other pathogens, active suppression of host defence is a critical component for successful parasitism by nematodes and a vulnerable target to disrupt the parasitic cycle.