A close-up of regulatory networks and signaling pathways of MKK5 in biotic and abiotic stresses.

Mitogen-activated protein Kinase Kinase 5 (MKK5) is a central hub in the complex phosphorylation chain reaction of the Mitogen-activated protein kinases (MAPK) cascade, regulating plant responses to biotic and abiotic stresses. This review manuscript aims to provide a comprehensive analysis of the regulatory mechanism of the MKK5 involved in stress adaptation. This review will delve into the intricate post-transcriptional and post-translational modifications of the MKK5, discussing how they affect its expression, activity, and subcellular localization in response to stress signals. We also discuss the integration of the MKK5 into complex signaling pathways, orchestrating plant immunity against pathogens and its modulating role in regulating abiotic stresses, such as: drought, cold, heat, and salinity, through the phytohormonal signaling pathways. Furthermore, we highlight potential applications of the MKK5 for engineering stress-resilient crops and provide future perspectives that may pave the way for future studies. This review manuscript aims to provide valuable insights into the mechanisms underlying MKK5 regulation, bridge the gap from numerous previous findings, and offer a firm base in the knowledge of MKK5, its regulating roles, and its involvement in environmental stress regulation.

Outbreak of Septoria leaf spot caused by Sphaerulina musiva on Populus × euramericana in China.

In June 2023, severe leaf spots were noted in Populus × euramericana cv 'Nanlin95' plantations located in the Nanjing Baguazhou Wetland Park (32°09'16.97″N, 118°48'16.74″E) of Jiangsu Province and Populus × canadensis cv 'Sacrau 79' and Populus × canadensis cv 'Guariento' in the Liyuan Village in Nanyang City (32°53'43.70″N, 112°17'29.12″E) of Henan Province, respectively. The disease incidence in both locations could reach 97.9% (556 out of 568 trees) and 98.9% (2409 out of 2436 trees), respectively. The initial symptoms appear as numerous small and circular spots (1.59 to 3.18 mm in diameter) with gray or tan centers and dark-brown margins on the leaves. As the spots age, they sometimes enlarge, often coalesce, and may extend down the petioles. Diseased leaves and petioles were both surface sterilized with 75% ethanol for 30 seconds. With the aid of a hand lens, pycnidia (brown to black, spherical in profile, 90 to 250 µm diam) were easily picked out in the center of the spots and subsequently transferred into 1 mL sterilized water for preparing the spore suspension plated on KV8 medium amended with 100 mg/liter streptomycin sulfate and 50 mg/liter chloramphenicol. After 12 days of incubation, 86 single-spore isolates were obtained and identified as typical Septoria-like fungi according to morphological features, including slow-growing, gray or black colonies with pink mucilaginous matrix and hyaline, straight or curved conidia (size = 25 to 59 × 3.5 to 4 µm; septa = 1 to 6). Species identification was further validated by PCR amplification and sequencing of the internal transcribed spacer (ITS) region with ITS1/ITS4 primer pairs. Multiple sequence alignments with ClustalW revealed that the obtained ITS sequences of 86 isolates were 100% identical to each other. A BLAST search in GenBank indicated that the selfsame sequences of two representative isolates (isolate BGZ11 of Jiangsu Province, accession no. OR660379; isolate KZB22 of Henan Province, accession no. OR711499) shared 99.8% identity (494 of 495 bp) and 100% identity (504 of 504 bp) with related sequences of Sphaerulina musiva (Peck) Quaedvlieg, Verkley, and Crous (syn. = Septoria musiva Peck) in GenBank (MN275187; KF251619), respectively. Furthermore, we used a S. musiva-specific PCR assay (Abraham et al. 2018) on symptomatic leaf samples collected from the plantation. Each sample consisted of 20 cut-out leaf spots per leaf. Eight of the 10 samples were positive for S. musiva DNA. To confirm pathogenicity, six sterile tissue culture of poplar plants (Populus trichocarpa and Populus × euramericana cv 'Nanlin895') were respectively transplanted into pots and grown in a greenhouse for a week and for a month with an 18-h photoperiod augmented with sodium lamps and a 20°C (day)/16°C (night) temperature regime. Inoculations were conducted by spraying the plants with conidia suspension (106 conidia/mL) (LeBoldus et al. 2010). Control plants were sprayed with distilled water. Leaf spots were developed on the inoculated P. trichocarpa leaves at one week and P. × euramericana cv 'Nanlin895' leaves at 10 days after inoculation while no symptoms were observed on the control plants. The fungus S. musiva was successfully reisolated from all symptomatic leaves fulfilling Koch's postulates. Sphaerulina musiva only causes an endemic leaf spot disease on its natural North American host Populus. deltoides (Feau et al. 2010; Ostry 1987). However, on susceptible Populus species (e.g., P. balsamifera, P. trichocarpa, P. maximowiczii) and hybrids, S. musiva causes not only leaf spots but also severely damaging stem and branch cankers (Jeger et al. 2018; LeBoldus et al. 2009; Sondreli et al. 2020). To our knowledge, this is the first report of S. musiva causing leaf spots on poplar in China. Large-scale timber imports (e.g., cut branches, isolated bark, wood with and without bark) potentially lead to anthropogenic-facilitated transport of this pathogen. This outbreak of Septoria leaf spot underscores the potential threat of this pathogen to P. × euramericana in China, where it is widely planted as a keystone forestry species.

Microbiome-Mediated Protection against Pathogens in Woody Plants.

Pathogens, especially invasive species, have caused significant global ecological, economic, and social losses in forests. Plant disease research has traditionally focused on direct interactions between plants and pathogens in an appropriate environment. However, recent research indicates that the microbiome can interact with the plant host and pathogens to modulate plant resistance or pathogen pathogenicity, thereby altering the outcome of plant-pathogen interactions. Thus, this presents new opportunities for studying the microbial management of forest diseases. Compared to parallel studies on human and crop microbiomes, research into the forest tree microbiome and its critical role in forest disease progression has lagged. The rapid development of microbiome sequencing and analysis technologies has resulted in the rapid accumulation of a large body of evidence regarding the association between forest microbiomes and diseases. These data will aid the development of innovative, effective, and environmentally sustainable methods for the microbial management of forest diseases. Herein, we summarize the most recent findings on the dynamic structure and composition of forest tree microbiomes in belowground and aboveground plant tissues (i.e., rhizosphere, endosphere, and phyllosphere), as well as their pleiotropic impact on plant immunity and pathogen pathogenicity, highlighting representative examples of biological control agents used to modulate relevant tree microbiomes. Lastly, we discuss the potential application of forest tree microbiomes in disease control as well as their future prospects and challenges.

Identification and immunoinfiltration analysis of key genes in ulcerative colitis using WGCNA.

Objective: Ulcerative colitis (UC) is a chronic non-specific inflammatory bowel disease characterized by an unclear pathogenesis. This study aims to screen out key genes related to UC pathogenesis. Methods: Bioinformatics analysis was conducted for screening key genes linked to UC pathogenesis, and the expression of the screened key genes was verified by establishing a UC mouse model. Results: Through bioinformatics analysis, five key genes were obtained. Subsequent infiltration analysis revealed seven significantly different immune cell types between the UC and general samples. Additionally, animal experiment results illustrated markedly decreased body weight, visible colonic shortening and damage, along with a significant increase in the DAI score of the DSS-induced mice in the UC group in comparison with the NC group. In addition, H&E staining results demonstrated histological changes including marked inflammatory cell infiltration, loss of crypts, and epithelial destruction in the colon mucosa epithelium. qRT-PCR analysis indicated a down-regulation of ABCG2 and an up-regulation of IL1RN, REG4, SERPINB5 and TRIM29 in the UC mouse model. Notably, this observed trend showed a significant dependence on the concentration of DSS, with the mouse model of UC induced by 7% DSS demonstrating a more severe disease state compared to that induced by 5% DSS. Conclusion: ABCG2, IL1RN, REG4, SERPINB5 and TRIM29 were screened out as key genes related to UC by bioinformatics analysis. The expression of ABCG2 was down-regulated, and that of IL1RN, REG4, SERPINB5 and TRIM29 were up-regulated in UC mice as revealed by animal experiments.

Role of stemness-related genes TIMP1, PGF, and SNAI1 in the prognosis of colorectal cancer through single-cell RNA-seq.

BACKGROUND: Colorectal cancer (CRC) is a fatal malignant tumor with poor prognosis. Cancer stem cells (CSCs) can cause metastasis, recurrence and drug resistance in CRC. This research aimed to analyze stemness-related prognostic genes of CRC based on single-cell RNA-sequencing (scRNA-seq) data. METHODS: DESeq2 was applied to analyze the differentially expressed genes (DEGs). The mRNA stemness index (mRNAsi) was calculated by one-class logistic regression (OCLR). The stemness-related cells were analyzed based on scRNA-seq dataset GSE166555. Monocle 2 algorithm was used for stemness-related cells pseudotime trajectory analysis. The stemness-related prognostic genes were analyzed by clusterProfiler and survival package. The stemness of CRC cells was detected by spheroid formation assay, and the expression of stemness-related prognostic genes was verified by qRT-PCR and Western blot. RESULTS: 7916 DEGs between the CRC and normal tissues were obtained. The mRNAsi of the CRC tissues was shown to be significantly higher than that of the normal tissues. 7 and 8 cell types were annotated respectively in the normal and CRC tissues through analysis of the scRNA-seq data. Cell-cell interactions (CCIs) in the tumor tissues were revealed to be significantly enhanced than that in the normal tissues. By calculating the 'stemness score', CSCs, epithelial cells (EPCs) and cancer-associated fibroblasts (CAFs) were defined as stemness-related cells. Through pseudotime trajectory analysis, 2111 genes were identified as state 2-specific genes. Then, 41 genes were obtained by taking intersection of the up-regulated genes with state 2-specific genes and marker genes of CSCs, EPCs and CAFs. The univariate COX regression analysis revealed 5 stemness-related prognostic genes (TIMP1, PGF, FSTL3, SNAI1 and FOXC1). Kaplan-Meier curve analysis indicated that the higher the expression of 5 genes, the lower the survival rate. In vitro cell experiment confirmed that the expression of TIMP1, PGF and SNAI1 was consistent with that revealed by bioinformatics analysis. CONCLUSIONS: TIMP1, PGF and SNAI1 were identified as stemness-related prognostic genes of CRC, and possibly potential therapeutic targets for CRC.

Extensively infarcted giant solitary hamartomatous polyp treated with endoscopic full-thickness resection: A case report.

BACKGROUND: Solitary hamartomatous polyps (SHPs) are rare lesions. Endoscopic full-thickness resection (EFTR) is a highly efficient and minimally invasive endoscopic procedure that benefits from complete lesion removal and high safety. CASE SUMMARY: A 47-year-old man was admitted to our hospital after experiencing hypogastric pain and constipation for over fifteen days. Computed tomography and endoscopy revealed a giant pedunculated polyp (approximately 18 cm long) in the descending and sigmoid colon. This is the largest SHP reported to date. Having considered the condition of the patient and mass growth, the polyp was removed using EFTR. CONCLUSION: On the basis of clinical and pathological evaluations, the mass was considered an SHP.

Inhibition of LncRNA-NEAT1 alleviates intestinal epithelial cells (IECs) dysfunction in ulcerative colitis by maintaining the homeostasis of the glucose metabolism through the miR-410-3p-LDHA axis.

Dysfunction of intestinal epithelial cells (IECs) leads to intestinal epithelial barrier damage and critically involves in the pathogenesis and development of ulcerative colitis (UC). Accumulating studies revealed essential functions of non-coding RNAs in UC. LncRNA NEAT1 (long non-coding RNA nuclear paraspeckle assembly transcript 1) is frequently dysregulated in diverse human diseases. Currently, the precise roles of NEAT1 in the dysfunction of IECs during UC remain unclear. We report NEAT1 was significantly upregulated in IECs from UC patients. In addition, microRNA-410-3p was remarkedly suppressed in IECs from UC patients. Silencing NEAT1 effectively ameliorates the LPS-induced IECs dysfunction. Bioinformatical analysis, RNA pull-down and luciferase assays illustrated that NEAT1 sponged miR-410-3p to downregulate its expression in IECs. Interestingly, the glucose metabolism was obviously elevated in IECs from UC compared with normal colon tissues. Furthermore, NEAT1 promoted and miR-410-3p suppressed glucose metabolism of IECs. We identified lactate dehydrogenase A (LDHA), a glucose metabolism key enzyme, was a direct target of miR-410-3p in IECs. Rescue experiments verified that restoration of miR-410-3p in NEAT1-overexpressing IECs successfully overcame the NEAT1-promoted cell death under LPS treatment by targeting LDHA. In summary, these results unveiled new roles and molecular mechanisms for the NEAT1-mediated IECs dysfunction during the ulcerative colitis.