Solanum tuberosum glucan synthase-like 05 is involved in root-knot nematode Meloidogyne hapla parasitism

The Glucan Synthase-like 5 (GSL05) gene in potato is homologous to the Arabidopsis GSL05 that has a role in defense-related callose deposition. The role of GSL05-mediated callose deposition in potato roots during root-knot nematode Meloidogyne hapla infection was investigated. Silencing GSL05 in potato resulted in reduced elicitor-induced callose deposition in roots. When StGSL05 knockdown plants were inoculated with nematodes, more second-stage juveniles (J2s) successfully penetrated the roots and formed galls, suggesting a weakened callose-based physical barrier against nematode invasion and supporting the hypothesis that StGSL05 contributes to basal defense. Despite the increased nematode penetration and gall formation, the StGSL05 knockdown plants did not exhibit more egg masses or total number of eggs. This suggested that while more nematodes penetrated, fewer progressed to reproductive maturity. Microscopic analysis revealed morphologically different feeding sites in the knockdown plants, indicating that disrupted callose deposition may impair feeding cell function, which is critical for nematode parasitism. These findings underscore the dual role of callose: while it provides early defense against nematode invasion, its disruption can also interfere with the feeding cell morphology. It highlights a nuanced role for callose in early defense and its potential for enhancing crop resistance to root-knot nematodes.