Submitted to: PLoS Pathogens
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/1/2025
Publication Date: 11/7/2025
Citation: Telxeira, M., Ko, I., Bali, S., Reis Vieira, P.C., Maier, T., Baum, T., Cynthia, G. 2025. Genome reannotation and gland-specific transcriptome analysis identify new effector candidates in Meloidogyne chitwoodi. PLoS Pathogens. 21(11). Article e1013075. https://doi.org/10.1371/journal.ppat.1013075.
DOI: https://doi.org/10.1371/journal.ppat.1013075

Interpretive Summary: A significant problem for potato production in the western USA is the root-knot nematode (round worm). It reduces both crop yield and value and is considered a quarantine pest in certain export markets. Its presence in a shipment bound for such a market could result in the rejection of the entire shipment. To develop new strategies for management, information is needed about how successful it is at causing disease and which genes contribute to the disease process. In this study, 111 candidate parasitism genes were identified. These data and results will be used by plant pathologists and plant breeders seeking to control this important nematode species by producing nematicides or resistant cultivars and by regulatory officials developing diagnostic assays for the root-knot nematode.

Technical Abstract: The root-knot nematode (RKN) Meloidogyne chitwoodi is a threat for potato production in the western United States, negatively impacting potato yield and product value. Meloidogyne chitwoodi produce proteins, called effectors, in their esophageal glands that are secreted during parasitism and play integral roles in plant-nematode interactions. Because the esophageal glands are the main effector secretory organ, we performed juvenile gland isolation and gland transcriptome analysis. The data allowed us to improve the M. chitwoodi genome annotation. Additionally, the gland-specific transcriptome data gave us an enrichment of gland-localized genes, which was validated by in situ hybridization. The gland transcriptome analysis led to the identification of 111 effector candidates. One of the effectors, Mc15g003960, which was highly expressed in the pre-parasitic J2 gland tissue, was further characterized. Expression of Mc15g003960 in Arabidopsis resulted in increased galling by M. chitwoodi. However, the ectopic expression of Mc15g003960 in planta did not suppress defense-related callose deposition, suggesting that this effector might be involved in processes other than interfering with plant basal defense responses. Our data shows that using the gland transcriptome, good quality genome annotation and stringent criteria, we can increase the efficiency of effectors identification, which can be used to develop more sustainable management tools.