RESUMO
Glomerella leaf spot (GLS), caused by Colletotrichum fructicola (Cf), has been one of the main fungal diseases afflicting apple-producing areas across the world for many years, and it has led to substantial reductions in apple output and quality. HD-Zip transcription factors have been identified in several species, and they are involved in the immune response of plants to various types of biotic stress. In this study, inoculation of MdHB-7 overexpressing (MdHB-7-OE) and interference (MdHB-7-RNAi) transgenic plants with Cf revealed that MdHB-7, which encodes an HD-Zip transcription factor, adversely affects GLS resistance. The SA content and the expression of SA pathway-related genes were lower in MdHB-7-OE plants than in 'GL-3' plants; the content of ABA and the expression of ABA biosynthesis genes were higher in MdHB-7-OE plants than in 'GL-3' plants. Further analysis indicated that the content of phenolics and chitinase and ß-1, 3 glucanase activities were lower and H2O2 accumulation was higher in MdHB-7-OE plants than in 'GL-3' plants. The opposite patterns were observed in MdHB-7-RNAi apple plants. Overall, our results indicate that MdHB-7 plays a negative role in regulating defense against GLS in apple, which is likely achieved by altering the content of SA, ABA, polyphenols, the activities of defense-related enzymes, and the content of H2O2.
Assuntos
Colletotrichum , Resistência à Doença , Malus , Doenças das Plantas , Proteínas de Plantas , Fatores de Transcrição , Malus/genética , Malus/microbiologia , Malus/metabolismo , Malus/imunologia , Colletotrichum/fisiologia , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Resistência à Doença/genética , Doenças das Plantas/microbiologia , Doenças das Plantas/genética , Doenças das Plantas/imunologia , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo , Regulação da Expressão Gênica de Plantas , Plantas Geneticamente Modificadas/genética , Folhas de Planta/microbiologia , Folhas de Planta/metabolismo , Folhas de Planta/genéticaRESUMO
BACKGROUND: Epigenetic changes of lung adenocarcinoma (LUAD) have been reported to be a relevant factor in tumorigenesis and cancer progression. However, the molecular mechanisms responsible for DNA methylation patterns in the tumor immune-infiltrating microenvironment and in cancer immunotherapy remain unclear. METHODS: We conducted a global analysis of the DNA methylation modification pattern (DMP) and immune cell-infiltrating characteristics of LUAD patients based on 21 DNA methylation regulators. A DNA methylation score (DMS) system was constructed to quantify the DMP model in each patient and estimate their potential benefit from immunotherapy. RESULTS: Two DNA methylation modification patterns able to distinctly characterize the immune microenvironment characterization were identified among 513 LUAD samples. A lower DMS, characterized by increased CTLA-4/PD-1/L1 gene expression, greater methylation modifications, and tumor mutation burden, characterized a noninflamed phenotype with worse survival. A higher DMS, characterized by decreased methylation modification, a greater stromal-relevant response, and immune hyperactivation, characterized an inflamed phenotype with better prognosis. Moreover, a lower DMS indicated an increased mutation load and exhibited a poor immunotherapeutic response in the anti-CTLA-4/PD-1/PD-L1 cohort. CONCLUSION: Evaluating the DNA methylation modification pattern of LUAD patients could enhance our understanding of the features of tumor microenvironment characterization and may promote more favorable immunotherapy strategies.