Background: Root-knot nematode is one of the most significant diseases of vegetable crops in the world. Biological control with microbial antagonists has been emerged as a promising and eco-friendly treatment to control pathogens. The aim of this study was to screen and identify novel biocontrol agents against root-knot nematode, Meloidogyne incognita. Results: A total of 890 fungal isolates were obtained from rhizosphere soil of different crops and screened by nematicidal activity assays. Snef1910 strain showed high virulence against second stage juveniles (J2s) of M. incognita and identified as Trichoderma citrinoviride by morphology analysis and biomolecular assay. Furthermore, T. citrinoviride Snef1910 significantly inhibited egg hatching with the hatching inhibition percentages of 90.27, 77.50, and 67.06% at 48, 72, and 96 h after the treatment, respectively. The results of pot experiment showed that the metabolites of T. citrinoviride Snef1910 significantly decreased the number of root galls, J2s, and nematode egg masses and J2s population density in soil and significantly promoted the growth of tomato plants. In the field experiment, the biocontrol application showed that the control efficacy of T. citrinoviride Snef1910 against root-knot nematode was more than 50%. Meanwhile, T. citrinoviride Snef1910 increased the tomato plant biomass. Conclusions: T. citrinoviride strain Snef1910 could be used as a potential biological control agent against root-knot nematode, M. incognita.

Soybean cyst nematode Heterodera glycines (SCN) is a major threat to global soybean production. Effective management of this disease is dependent on the development of resistant cultivars. Two SCN HG Types, 7 and 1.3.4.7. were previously identified as prevalent H. glycines populations in Northeast China. In order to evaluate soybean cultivars resistant to local SCN populations, 110 domestic commercial soybeans from different regions of Northeast China were assessed in the greenhouse to determine their potential as novel sources of resistance. The results suggested that cultivars responded differently to the two HG types. Of the 110 soybean cultivars evaluated, 24 accessions were classified as resistant or moderately resistant to HG Type 7, and five cultivars were classified as resistant or moderately resistant to HG Type 1.3.4.7. Among the tested cultivars, Kangxian 12 and Qingdou 13 had resistance response to both HG types 7 and 1.3.4.7. Thus, these broad-based SCN cultivars will be the valuable materials in the SCN resistance breeding program.

With-no-lysine kinase (WNK) is a unique serine/threonine kinase family member. WNK differs from other protein kinases by not having a standard lysine in subdomain II of the universally preserved kinase catalytic region. Conversely, the amino acid lysine located in subdomain I plays a crucial role in its phosphorylation. The WNK family has been reported to regulate Arabidopsis flowering, circadian rhythm, and abiotic stress. Eighteen members of the WNK gene family were discovered in apples in this research, and they were primarily grouped into five categories on the phylogenetic tree. Conserved domains and motifs also confirmed their identity as members of the WNK family. Promoter cis-acting element analysis indicated their potential role in responses to both abiotic stress and phytohormones. Furthermore, qRT-PCR analysis showed that the expression of MdWNK family genes was stimulated to different extents by Colletotrichum siamense, NaCl, mannitol, ABA, JA, and SA, with Colletotrichum siamense being the most prominent stimulant. MdWNK family genes were expressed across all apple tissues, with young fruits showing the greatest expression and roots showing the least expression. The research offered detailed insights into the MdWNK gene family, serving as a crucial basis for investigating the biological roles of MdWNK genes.

Wheat stem rust, caused by Puccinia graminis f. sp. tritici, is a major disease that severely affects safe wheat production. The Huanghuai region plays a vital role in China’s wheat production and the wheat stem rust epidemic across China. However, due to China’s effective control measures, wheat stem rust rarely occurs in the region, resulting in little research on this disease, including the determination of resistance genes in cultivars and elite lines. For this purpose, this study utilized two predominant races (21C3CTHQM and 34MKGQM) of P. graminis f. sp. tritici to determine the resistance levels of 64 wheat cultivars in the Huanghuai wheat region. Additionally, molecular markers linked with Sr24, Sr25, Sr26, Sr31, and Sr38 were used to analyze the presence of these genes. The results indicated that among the 62 wheat cultivars and elite lines, 13 cultivars contained Sr31, four cultivars were detected to contain Sr38, and none contained Sr24, Sr25, or Sr26. Field tests in 2023 showed that three (4.8%) cultivars exhibited immunity to both races, while 20 (32.3%) and 23 (37.1%) cultivars showed resistance to moderate resistance, and 39 (62.9%) and 36 (58.1%) cultivars were moderately susceptible to susceptible. In 2024, one (1.6%) and four (6.5%) cultivars demonstrated immunity to both races, 22 (35.5%) and 23 (37.1%) cultivars showed resistance to moderate resistance, and 39 (62.9%) and 35 (56.5%) cultivars were moderately susceptible to susceptible. With over 50% of the cultivars displaying susceptibility, the overall resistance level was relatively low, indicating that stem rust outbreaks could recur if a sufficient inoculum is present. It is crucial to explore new resistance sources, discover novel resistance genes, and breed wheat cultivars with durable resistance and desirable agronomic traits to enhance the overall resistance to stem rust in Chinese wheat-growing regions.

Root-knot nematodes (Meloidogyne spp.) cause catastrophic yield losses in global agriculture. This study identified itaconic acid (IA), through comparative metabolomic analysis (the study of small molecules in biological systems), as a key virulence-related metabolite produced by the fungus Trichoderma citrinoviride Snef1910. In vitro assays demonstrated potent nematicidal activity of IA, with an LC ₅₀ value of 243.4 mg/liter against J2s of M. incognita and 78.4% egg-hatching inhibition at 800 mg/liter, performance that is comparable with the structural analog trans-aconitic acid. Pot and greenhouse field trials demonstrated that IA has a significant impact against M. incognita while enhancing tomato growth. Seed priming with IA compensated for the damage of nematodes to the photosynthetic pigments and activated systemic resistance of tomatoes, and treatment with 100 mg/liter of IA enhanced catalase and ascorbate peroxidase activities, while concurrently inhibiting H ₂ O ₂ /MDA accumulation. Crucially, IA production by T. citrinoviride positions this strain as a self-fertilizing organism for production of a nematicide with plant-growth-promoting properties. This study highlights the dual functionality of IA in nematode management, offering a sustainable alternative to synthetic agrochemicals.