Root-knot nematodes (RKNs) are the most economically damaging plant-parasitic nematodes globally. Xinjiang, encompassing one-sixth of China's landmass, currently lacks comprehensive data regarding the occurrence, distribution, and genetic variation of RKNs infecting vegetables within its borders. Hence, identifying RKNs species and genetic diversity is crucial for devising comprehensive management strategies. Between 2021 and 2023, We present a survey of 130 samples, collected from 86 counties across 14 cities in Xinjiang, aiming to comprehensively understand the occurrence, distribution, damage, and species of vegetable RKNs. The results indicated that 57 out of 130 samples collected from the cities of Hami, Tulufan, Ili, Bayingol, Hotan, Aksu, Kashgar, and Kizilsu in Xinjiang were infected by RKNs, suggesting an expansion of RKN disease in the vegetable-producing regions of Xinjiang. The infected vegetable roots were found to harbor Meloidogyne incognita and M. hapla, with M. incognita being the most prevalent species. A phylogenetic analysis targeting the COI regions of M. incognita revealed significant evolutionary and genetic disparities between Xinjiang and Southeastern China RKN populations. Haplotype analysis of the COI gene revealed that M. incognita populations are categorized into three major lineages: Asia, Europe, and a combined lineage encompassing both America and Africa. Notable gene flow patterns were observed among M. incognita populations, with significant migrations from Europe and America to Asia, specifically from Southeastern China towards Xinjiang. This study's findings indicate a consistent increase in the detrimental effects of vegetables production caused by RKNs in Xinjiang. Implementing effective prevention and control measures is crucial to mitigate the spread of RKNs.

The rice white tip nematode (RWTN) Aphelenchoides besseyi secretes effectors that manipulate host plant cells to facilitate successful parasitism and sustain infection.  Although the number of identified RWTN effectors remains limited, their mechanisms of interaction with host plants are largely unknown.  Profilins (PFNs) function as molecular hubs that regulate complex interaction networks.  To advance understanding of PFN3 in plant-parasitic nematodes, we identified an effector from A. besseyi, designated AbPFN3.  AbPFN3 is transcriptionally upregulated during the juvenile stage of the nematode, and in situ hybridization localized its expression to the esophageal glands.  Three rice (Oryza sativa) proteins, ADP/ATP carrier protein 1 (OsAAC1), B-cell receptor-associated protein 31 (OsBAP31) and Small Auxin Up RNA 50 (OsSAUR50), were identified as interactors of AbPFN3, with interactions occurring in distinct cellular compartments, including the endoplasmic reticulum, cytoplasm, and plasma membrane.  Transgenic analyses revealed that AbPFN3 expression significantly increased plant height and upregulated AAC1 and BAP31, while downregulating RGA2 and SAUR50.  This study characterizes AbPFN3 as a novel effector secreted by A. besseyi that interacts with multiple host proteins, highlighting its potential role in modulating host defense responses and cell development processes.

The sugar beet cyst nematode (Heterodera schachtii) is one of the most destructive pathogens in sugar beet production, which causes serious economic losses every year.  Few molecular details of effectors of H. schachtii parasitism are known.  We analyzed the genome and transcriptome data of H. schachtii and identified multiple potential predicted proteins.  After filtering out predicted proteins with high homology to other plant-parasitic nematodes, we performed functional validation of the remaining effector proteins.  37 putative effectors of H. schachtii were screened based on the Nicotiana benthamiana system for identifying the effectors that inhibit plant immune response, eventually determines 13 candidate effectors could inhibit cell death caused by Bax.  Among the 13 effectors, nine have the ability to inhibit GPA2/RBP1-induced cell death.  All 13 effector-triggered immunity (ETI) suppressor genes were analyzed by qRT-PCR and confirmed to result in a significant downregulation of one or more defense genes during infection compared to empty vector.  For in situ hybridization, 13 effectors were specifically expressed and located in esophageal gland cells.  These data and functional analysis set the stage for further studies on the interaction of H. schachtii with host and H. schachtii parasitic control.