Molecular Cloning of HbPR-1 Gene from Rubber Tree, Expression of HbPR-1 Gene in Nicotiana benthamiana and Its Inhibition of Phytophthora palmivora

Genome-Wide Identification and Expression Profiling of Pathogenesis-Related Protein 1 (PR-1) Genes in Durum Wheat (Triticum durum Desf.)

Pathogen-related proteins (PRs) are diversified proteins with a low molecular weight implicated in plant response to biotic and abiotic stress as well in regulating different functions in plant maturation. Interestingly, no systematical study has been conducted in durum wheat (Triticum turgidum subsp. durum). In the present study, 12 PR-1 genes encoding a CAP superfamily domain were identified in the genome of Triticum turgidum subsp. durum, which is an important cereal, using in silico approaches. Additionally, phylogenetic analysis showed that the PR-1 genes were classified into three groups based on their isoelectric point and the conserved motif domain. Moreover, our analysis showed that most of the TdPR-1 proteins presented an N-terminal signal peptide. Expression patterns analysis showed that the PR-1 gene family presented temporal and spatial specificity and was induced by different abiotic stresses. This is the first report describing the genome-scale analysis of the durum wheat PR-1 gene family, and these data will help further study the roles of PR-1 genes during stress responses, leading to crop improvement.

NR4A2 may be a potential diagnostic biomarker for myocardial infarction: A comprehensive bioinformatics analysis and experimental validation

Background

Myocardial infarction is a well-established severe consequence of coronary artery disease. However, the lack of effective early biomarkers accounts for the lag time before clinical diagnosis of myocardial infarction. The present study aimed to predict critical genes for the diagnosis of MI by immune infiltration analysis and establish a nomogram.

Methods

Gene microarray data were downloaded from Gene Expression Omnibus (GEO). Differential expression analysis, single-cell sequencing, and disease ontology (DO) enrichment analysis were performed to determine the distribution of Differentially Expressed Genes (DEGs) in cell subpopulations and their correlation with MI. Next, the level of infiltration of 16 immune cells and immune functions and their hub genes were analyzed using a Single-sample Gene Set Enrichment Analysis (ssGSEA). In addition, the accuracy of critical markers for the diagnosis of MI was subsequently assessed using receiver operating characteristic curves (ROC). One datasets were used to test the accuracy of the model. Finally, the genes with the most diagnostic value for MI were screened and experimentally validated.

Results

335 DEGs were identified in GSE66360, including 280 upregulated and 55 downregulated genes. Single-cell sequencing results demonstrated that DEGs were mainly distributed in endothelial cells. DO enrichment analysis suggested that DEGs were highly correlated with MI. In the MI population, macrophages, neutrophils, CCR, and Parainflammation were significantly upregulated compared to the average population. NR4A2 was identified as the gene with the most significant diagnostic value in the immune scoring and diagnostic model. 191 possible drugs for the treatment of myocardial infarction were identified by drug prediction analysis. Finally, our results were validated by Real-time Quantitativepolymerase chain reaction and Western Blot of animal samples.

Conclusion

Our comprehensive in silico analysis revealed that NR4A2 has huge prospects for application in diagnosing patients with MI.

A secreted protein of 15 kDa plays an important role in Phytophthora palmivora development and pathogenicity

Phytophthora palmivora is a destructive oomycete plant pathogen with a wide host range. So far, little is known about the factors governing its infection structure development and pathogenicity. From the culture filtrate of a P. palmivora strain isolated from papaya, we identified a secreted glycoprotein of 15 kDa, designated as Ppal15kDa, using liquid chromatography tandem mass spectrometry. Two gene variants, Ppal15kDaA and Ppal15kDaB were amplified from a P. palmivora papaya isolate. Transient expression of both variants in Nicotiana benthamiana by agroinfiltration enhanced P. palmivora infection. Six Ppal15kDa mutants with diverse mutations were generated via CRISPR/Cas9-mediated gene editing. All mutants were compromised in infectivity on N. benthamiana and papaya. Two mutants with all Ppal15kDa copies mutated almost completely lost pathogenicity. The pathogenicity of the other four containing at least one wild-type copy of Ppal15kDa was compromised at varying levels. The mutants were also affected in development as they produced smaller sporangia, shorter germ tubes, and fewer appressoria. The affected levels in development corresponded to the levels of reduction in pathogenicity, suggesting that Ppal15kDa plays an important role in normal development of P. palmivora infection structures. Consistent with its role in infection structure development and pathogenicity, Ppal15kDa was found to be highly induced during appressorium formation. In addition, Ppal15kDa homologs are broadly present in Phytophthora spp., but none were characterized. Altogether, this study identified a novel component involved in development and pathogenicity of P. palmivora and possibly other Phytophthora spp. known to contain a Ppal15kDa homolog.

Sulphated Polysaccharide from Acanthophora spicifera Induced Hevea brasiliensis Defense Responses Against Phytophthora palmivora Infection

Elicitors from seaweeds are considered an alternative stimulant of plant defenses against pathogenic infection. Finding new sources of elicitors and exploring their effects on plant defenses is a significant undertaking. In this study, we extracted crude polysaccharide (CPS) from Acanthophora spicifera (a red alga) and tested the effects of the compound on rubber tree (Hevea brasiliensis) defense responses. Accumulations of salicylic acid (SA) and scopoletin (Scp) were measured by HPLC. The expression of SA- and Jasmonic acid (JA)-responsive genes was analyzed by semi-qRT-PCR. Strong anion exchange chromatography and Fourier-transform infrared (FTIR) spectroscopy were used for purification and functional characterization of CPS, respectively. The extracted CPS enhanced rubber tree defenses against Phytophthora palmivora infection. It induced SA and Scp accumulations and SA-responsive gene expression, but suppressed JA-responsive gene expression. We successfully separated the non-sulphated polysaccharide (F1) from the sulphated polysaccharides (SPS). Both peaks of SPS (F2 and F3) were identified as lambda (λ)-carrageenan. The F3 fraction showed greater elicitor activity on tobacco leaves. It induced SA and Scp accumulations and peroxidase activity but suppressed catalase activity. Furthermore, the purified λ-carrageenan did not cause cell death in tobacco or rubber tree leaves. Therefore, the elicitor from A. spicifera could be an alternative plant stimulant.

Phenotypic Characterization of Genetically Distinct Phytophthora cinnamomi Isolates from Avocado

Phytophthora cinnamomi, the causal agent of Phytophthora root rot (PRR), is the most destructive disease of avocado worldwide. A previous study identified two genetically distinct clades of A2 mating type avocado isolates in California; however, the phenotypic variation among them was not assessed. This study described the phenotype of a subset of isolates from these groups regarding growth rate, growth temperature, virulence, and fungicide sensitivity. Isolates corresponding to the A2 clade I group exhibited higher mycelial growth rate and sensitivity to higher temperatures than other isolates. Among the fungicides tested, potassium phosphite had the highest 50% effective concentration for mycelial growth inhibition and oxathiapiprolin had the lowest. Mycelial growth rate and potassium phosphite sensitivity phenotypes correlate with specific groups of isolates, suggesting that these traits could be a group characteristic. Moreover, isolates that are more virulent in avocado and less sensitive to potassium phosphite were identified. A detached-leaf P. cinnamomi inoculation method using Nicotiana benthamiana was developed and validated, providing an alternative method for assessing the virulence of a large number of isolates. This information will help avocado PRR management and assist breeding programs for the selection of rootstocks resistant against a more diverse pathogen population.

The plant defense and pathogen counterdefense mediated by Hevea brasiliensis serine protease HbSPA and Phytophthora palmivora extracellular protease inhibitor PpEPI10

Rubber tree (Hevea brasiliensis Muell. Arg) is an important economic crop in Thailand. Leaf fall and black stripe diseases caused by the aggressive oomycete pathogen Phytophthora palmivora, cause deleterious damage on rubber tree growth leading to decrease of latex production. To gain insights into the molecular function of H. brasiliensis subtilisin-like serine proteases, the HbSPA, HbSPB, and HbSPC genes were transiently expressed in Nicotiana benthamiana via agroinfiltration. A functional protease encoded by HbSPA was successfully expressed in the apoplast of N. benthamiana leaves. Transient expression of HbSPA in N. benthamiana leaves enhanced resistance to P. palmivora, suggesting that HbSPA plays an important role in plant defense. P. palmivora Kazal-like extracellular protease inhibitor 10 (PpEPI10), an apoplastic effector, has been implicated in pathogenicity through the suppression of H. brasiliensis protease. Semi-quantitative RT-PCR revealed that the PpEPI10 gene was significantly up-regulated during colonization of rubber tree by P. palmivora. Concurrently, the HbSPA gene was highly expressed during infection. To investigate a possible interaction between HbSPA and PpEPI10, the recombinant PpEPI10 protein (rPpEPI10) was expressed in Escherichia coli and purified using affinity chromatography. In-gel zymogram and co-immunoprecipitation (co-IP) assays demonstrated that rPpEPI10 specifically inhibited and interacted with HbSPA. The targeting of HbSPA by PpEPI10 revealed a defense-counterdefense mechanism, which is mediated by plant protease and pathogen protease inhibitor, in H. brasiliensis-P. palmivora interactions.