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Genetic analysis and culturing techniques for gastric non- Helicobacter pylori Helicobacter (NHPH) are progressing. NHPH is reported to accompany nodular gastritis, gastric MALT lymphoma, and mild gastritis. However, only a few gastric cancer cases infected by NHPH have been reported. PCR analysis specific for NHPH and H. pylori was performed for DNA from gastric mucosa of 282 Korean gastric cancer patients, who were treated with endoscopic submucosal dissection. For more precise strain detection of NHPH, NHPH-positive mucosa was stained by immunohistochemistry specific for Helicobacter suis . The Cancer Genome Atlas (TCGA) classification was analyzed for these 3 gastric cancer sub-groups by in situ hybridization and immunohistochemistry. Among 281 patients, 3 patients (1.1%) were positive for NHPH. One patient (Patient 1) was also positive for H. pylori by PCR, another patient (Patient 3) was positive for serum IgG for H. pylori , and the other patient (Patient 2) had no evidence for H. pylori infection. Gastric mucosa of Patients 2 and 3 were positive for H. suis staining. All three NHPH-positive gastric cancers were located in the antrum, and belonged to the Chromosomal Instability Type of TCGA classification. Gastric NHPH can be a cause of gastric cancer, although likely with lower pathogenesis than H. pylori .

Rhizoctonia solani is a soil-borne fungus causing sheath blight. In consistent with its necrotrophic life style, no rice cultivars fully resistant to R. solani are known, and agrochemical plant defense activators used for rice blast, which upregulate a phytohormonal salicylic acid (SA)-dependent pathway, are ineffective towards this pathogen. As a result of the unavailability of genetics, the infection process of R. solani remains unclear. We used the model monocotyledonous plants Brachypodium distachyon and rice, and evaluated the effects of phytohormone-induced resistance to R. solani by pharmacological, genetic and microscopic approaches to understand fungal pathogenicity. Pretreatment with SA, but not with plant defense activators used in agriculture, can unexpectedly induce sheath blight resistance in plants. SA treatment inhibits the advancement of R. solani to the point in the infection process in which fungal biomass shows remarkable expansion and specific infection machinery is developed. The involvement of SA in R. solani resistance is demonstrated by SA-deficient NahG transgenic rice and the sheath blight-resistant B. distachyon accessions, Bd3-1 and Gaz-4, which activate SA-dependent signaling on inoculation. Our findings suggest a hemi-biotrophic nature of R. solani, which can be targeted by SA-dependent plant immunity. Furthermore, B. distachyon provides a genetic resource that can confer disease resistance against R. solani to plants.

To evaluate non-H. pylori Helicobacter (NHPH) infections in Japan, we enrolled 673 consecutive patients who underwent gastric endoscopy during annual medical checkups at 4 hospitals during April 2022-February 2023. We collected intragastric fluid and serum samples to detect NHPH infection by PCR and serologic tests. The prevalence of NHPH was 3% (20/673); 70% (14/20) of patients were infected with H. suis and 30% (6/20) with non-H. suis NHPH species. All 14 H. suis-infected patients were men and had a history of pork offal ingestion. Among non-H. suis NHPH-infected patients, 50% (3/6) owned pet cats, whereas only 22% (145/667) of other patients owned cats. Endoscopic evaluation revealed marbled crack-like gastritis was present in 93% (13/14) of H. suis-infected patients, a significantly higher prevalence than for H. pylori-infected (28.6%) and H. pylori eradication therapy (27.6%) groups. Pork offal ingestion and having pet cats increase risk for Helicobacter spp. infections.

We report the isolation of Helicobacter ailurogastricus, a Helicobacter species that infects cats and dogs, from a person with multiple refractory gastric ulcers. In addition to H. suis, which infects pigs, Helicobacter species that infect cats and dogs should be considered as potential gastric pathogens in humans.

-hydroxypipecolic acid (NHP) is a key mobile signal in systemic acquired resistance in plants, and its glycosylation has been proposed to regulate immune signaling. Previous studies have demonstrated that the UDP-glycosyltransferase UGT76B1, known as an SA glycosyltransferase in , also catalyzes NHP glycosylation. In this study, we re-evaluated NHP glycosylation activity of UGT76B1 using an in vitro enzyme-coupled fluorescence assay that quantitatively detects UDP released during UDP-sugar-dependent glycosylation. Unexpectedly, our biochemical analyses demonstrated that UGT76B1 lacks genuine glycosylation activity toward NHP under the in vitro assay conditions tested, although this system clearly detected UGT76B1 activity toward salicylic acid (SA), as well as the activities of UGT74F1 and UGT72B1 toward SA and hydroquinone, respectively. To explore potential UGTs responsible for NHP glycosylation, we evaluated the enzymatic activities of 41 UGT candidates successfully expressed in , which are selected based on transcriptomic responses to tenoxicam treatment, molecular docking simulations using AlphaFold3/AutoDock Vina, phylogenetic criteria, and previous reports. Within this selected and successfully expressed UGT panel, none exhibited authentic NHP glycosylation activity, although this does not preclude the possibility that other members of the Arabidopsis UGT family possess NHP glycosyltransferase activity. Our findings challenge the prevailing view that UGT76B1 is the primary glycosyltransferase for NHP in and indicate that NHP metabolism may rely on undiscovered non-canonical enzymes or distinct metabolic pathways that warrant further investigation.

is a necrotrophic phytopathogenic fungus that causes disease in various crops. In agriculture, many crops suffer from root or seedling rot caused by this soil-borne pathogen, whereas cabbage and rice develop lesion-like symptoms on aboveground tissues. Diseases caused by are generally controlled using chemical fungicides; however, environmentally friendly alternatives are needed for sustainable agriculture. In this study, we evaluated the efficacy of lecithin, a mixture of phospholipids previously registered in Japan as an agrochemical for controlling cucumber powdery mildew, against diseases. In cabbage, foliar spraying of 0.2-1.0% soybean lecithin effectively suppressed leaf symptoms caused by isolate RhiCa-2, which was identified as AG-1 IB. In rice and , 0.2-1.0% lecithin significantly suppressed leaf symptoms induced by AG-1 IA. Hyphal staining of inoculated leaves revealed reduced hyphal density on lecithin-treated leaves. Consistently, hyphal growth of on cellophane placed on water agar was retarded by lecithin treatment. However, 5.0% lecithin induced phytotoxicity in . Egg yolk-derived lecithin also exhibited disease-suppressive activity in cabbage and , with efficacy comparable to that of soybean lecithin under the conditions tested. These results suggest that lecithin suppresses foliar infection by , at least in part, through direct inhibitory effects on fungal hyphae, and may serve as a potential alternative material for disease control in sustainable crop production.

Rhizoctonia solani is a soil-borne phytopathogen with a broad host range, classified into multiple anastomosis groups (AGs). While the rice sheath blight pathogen AG-1 IA is well-studied, defense mechanisms against AG-4, which infects diverse monocots and dicots, remain unclear. Here, we screened 153 Brachypodium distachyon accessions for resistance to AG-4 HG-I+II using both leaf and soil inoculation assays. The accessions exhibited a quantitative resistance spectrum in both assays. Some accessions were resistant to both methods, while others showed resistance in only one, indicating that leaf and root defenses operate independently. Unlike the salicylic acid (SA)-dependent resistance observed in several accessions against AG-1 IA, AG-4 leaf resistance appears to be largely SA-independent. Among 22 resistant accessions, only eight induced the SA marker BdWRKY38 , whereas twelve induced the jasmonic acid (JA) marker BdAOS . Additionally, resistance in Bd3–1 was unaffected by expression of the SA hydroxylase NahG. These results are consistent with previous findings that exogenous application of SA, JA, or ethylene fails to confer AG-4 resistance. Instead, most AG-4-resistant accessions showed common upregulation of cell wall biosynthesis-related genes following leaf infection, suggesting that cell wall fortification may contribute to defense against AG-4. These findings establish B. distachyon as a valuable model for dissecting resistance mechanisms against R. solani AG-4.

Helicobacter cinaedi infects the human gut and causes invasive infections such as bacteremia and cellulitis through bacterial translocation. However, the mechanism by which H. cinaedi attaches to host cells and establishes infection remains unclear. This study aimed to investigate the relationship between a novel putative autotransporter protein, H. cinaedi autotransporter protein A (HcaA), and its role in pathogenicity. The cytotoxicity of H. cinaedi infection in colon epithelial cell lines (Caco-2 and HT29) was assessed using a lactate dehydrogenase assay, and it was found that cytotoxicity significantly decreased upon HcaA knockout. Adhesion assays further revealed that the HcaA-knockout strain showed significantly reduced attachment to the human epithelial colorectal adenocarcinoma (Caco-2) cell line compared to that of the wild-type strain. Moreover, the recombinant HcaA protein demonstrated strong adhesion properties to the human monocytic cell line (U937). The adhesive activity was diminished when the Arg-Gly-Asp (RGD) motif in HcaA was replaced with RAD, indicating that the RGD motif in HcaA is crucial for host cell adhesion. To determine the role of HcaA in H. cinaedi infection in vivo , C57BL/6 mice were orally infected with wild-type and HcaA-knockout H. cinaedi strains. Bacterial colonization was assessed 7, 14, and 28 days post-infection. At 7 days post-infection, colonization was significantly lower in mice infected with the HcaA-knockout strain compared to those infected with the wild-type strain. In conclusion, our findings suggest that HcaA, a novel putative autotransporter protein in H. cinaedi , plays a significant role as an adhesin in establishing colonization. Helicobacter species are classified as gastric or enterohepatic according to their habitat. Among enterohepatic Helicobacter species, which inhabit the intestine, colon, and liver, Helicobacter cinaedi has been most frequently isolated from humans. H. cinaedi often causes bacteremia and cellulitis in immunocompromised hosts. Here, we focused on the H. cinaedi autotransporter protein A (HcaA), a novel virulence factor in H. cinaedi . We discovered that HcaA contributes to cell adhesion via its Arg-Gly-Asp motif. Furthermore, in animal experiments, bacterial colonization was reduced in mice infected with HcaA-knockout strains, supporting the hypothesis that HcaA contributes to H. cinaedi adhesion to host cells. Our study provides a novel mechanism for the establishment of H. cinaedi infections and provides new insights into the role of autotransporter proteins in the establishment of Helicobacter infection.

Chitin, an N-acetyl-D-glucosamine polymer, is a component of fungal cell walls and a microbe/pathogen-associated molecular pattern that elicits plant defense responses. As polymeric chitin is difficult to handle due to its insolubility in water, many studies on chitin-induced immune responses have used water-soluble low-molecular weight chitin instead. Thus, it is unclear if polymeric chitin can induce resistance. Here, we examined the elicitor activity of chitin nanofiber (CNF) of submicron thickness prepared from polymeric chitin. CNF showed a high dispersing ability in water and induced both reactive oxygen species (ROS) production and chitin-induced defense-related gene expression in Arabidopsis thaliana seedlings. The Arabidopsis chitin elicitor receptor kinase 1 (Atcerk1) mutant, which is impaired in chitin perception, also failed to respond to CNF. CNF exposure triggered ROS generation in suspension-cultured cells from Oryza sativa. Furthermore, pre-treatment of Arabidopsis leaves with CNF effectively reduced pathogen infection by both the fungus Alternaria brassicicola and the bacterium Pseudomonas syringae pv. tomato DC3000. These results demonstrate that CNF has elicitor activity and will help define the role of polymeric chitin in plant immune responses.

Toll-like receptors (TLRs) recognize distinct microbial components and induce innate immune responses. TLR5 is triggered by bacterial flagellin. Here we generated Tlr5 −/− 1mice and assessed TLR5 function in vivo . Unlike other TLRs, TLR5 was not expressed on conventional dendritic cells or macrophages. In contrast, TLR5 was expressed mainly on intestinal CD11c + lamina propria cells (LPCs). CD11c + LPCs detected pathogenic bacteria and secreted proinflammatory cytokines in a TLR5-dependent way. However, CD11c + LPCs do not express TLR4 and did not secrete proinflammatory cytokines after exposure to a commensal bacterium. Notably, transport of pathogenic Salmonella typhimurium from the intestinal tract to mesenteric lymph nodes was impaired in Tlr5 −/− mice. These data suggest that CD11c + LPCs, via TLR5, detect and are used by pathogenic bacteria in the intestinal lumen.