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.

The strawberry crimp nematode (Aphelenchoides fragariae) is a serious pathogen of ornamental crops and an important quarantine object in approximately 50 countries and regions including China. One nematode population within the genus Aphelenchoides was discovered from diseased leaves of fuchsia plants (Fuchsia × hybrid Voss.) in Chengdu city, Sichuan province of China. Morphological and morphometric data were obtained using light microscopy and scanning electron microscopy. After detailed examination, the species was identified as A. fragariae. Three rDNA sequences of this species, including partial rRNA small subunit, D2-D3 expansion domains of the rRNA large subunit and internal transcribed spacer, were amplified and sequenced. Bayesian trees inferred from these three rDNA sequences were constructed, revealing that this species is placed in a high support monophyletic clade with A. fragariae but clearly separated from all other Aphelenchoides species. Moreover, host-suitability tests showed that the Aphelenchoides population not only can harm and reproduce in F. hybrid, but also in Fragaria ananassa and Pteris vittata (two common hosts of A. fragariae). In conclusion, the study confirmed A. fragariae identity of the nematode from F. hybrid in Chengdu city based on morphology, molecular analysis and host-suitability tests. To our knowledge, this is the first molecular and morphological confirmation of A. fragariae in China, and F. hybrid was first discovered to be attacked by A. fragariae.

The rice white tip nematode (RWTN) Aphelenchoides besseyi secretes effectors that manipulate the cells of its host plant and help the nematode to successfully parasitize and maintain infection in the host. The number of identified RWTN effectors is limited, and the mechanisms of RWTN effectors interacting with plants are largely unknown. Profilins (PFNs) function as hubs that control a complex network of molecular interactions. To gain full knowledge of PFN3 in plant parasitic nematodes, we identified an effector from A. besseyi named AbPFN3. AbPFN3 is transcriptionally upregulated in the juvenile stage of the nematode. In situ hybridization experiments showed that AbPFN3 transcribed in the nematode esophageal glands. Three AbPFN3-interacting proteins (OsAAC1, OsBAP31 and OsSAUR50) were found in the host plant, with interactions occurring in various locations such as the endoplasmic reticulum, cytoplasm, and plasma membrane. Transgenic analyses showed that the expression of AbPFN3 significantly increased plant height and upregulated the expression of AAC1 and BAP31 while downregulating RGA2 and SAUR50. This study describes a new effector protein, AbPFN3, secreted by A. besseyi, that interacts with multiple host proteins. These results suggest the important role of AbPFN3 in host defense response and cell development process.

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.