The methylation states of TEs may be key factors in regulating multiple genes simultaneously. In rice PigmS promoters, the methylation levels of TEs regulate expression in a tissue-specific manner and balance a high-resistance phenotype with low yield loss 17. The activation of TEs can regulate gene expression, and the activity of TEs is regulated by DNA methylation 16. Therefore, the insertion of TEs in genes is easily regulated by the RdDM pathway 15. Transposable elements (TEs) are the main sources of small RNAs in plants. Demeter (DME) and REPRESSOR OF SILENCING1 (ROS1) are involved in this process 9, 14. To balance genome methylation and maintain gene expression, plants utilize DNA demethylase to eliminate methylcytosines and replace them with unmethylated cytosine. The first step involves RNA polymerase (Pol) IV and DICER-LIKEs (DCLs), whereas the second step involves Pol V, ARGONAUTE4/6 (AGO4/6), and DRMs 12, 13. The RdDM pathway has two main steps: siRNA biogenesis and siRNA-guided DNA methylation. DOMAINS REARRANGED METHYLTRANSFERASE (DRM) 2 establishes de novo DNA methylation in three contexts through the RNA-directed DNA methylation (RdDM) pathway. In Arabidopsis, METHYLTRANSFERASE1 (MET1) maintains CG methylation (mCG), CHROMOMETHYLASE (CMT) 3 maintains CHG methylation (mCHG), and CMT2 maintains CHH methylation (mCHH) 10, 11. In plants, DNA methylation occurs in two contexts, symmetric (CG and CHG) and asymmetric (CHH), in which H may be A, T, or C. In Medicago truncatula, the differences in the transcript levels of the resistance gene REP1 are related to the methylation state of its promoter region, and REP1 is associated with resistance to Erysiphe pisi 8.ĭNA methylation is a conserved form of epigenetic marking that is related to immunity, genome stability, imprinting, and environmental responses 9, 10. Tobacco mosaic virus-induced DNA hypomethylation of LRRs is related to increased genomic rearrangements at these sites 7. The resistance of Arabidopsis dcl or rdr mutants to beet cyst nematodes ( Heterodera schachtii) is stronger than that of the wild type 6.
For instance, in Arabidopsis, DNA methylation controls defense responses to Pseudomonas syringae, and the overall destruction of methyl groups on DNA activates these responses 5. Methylation plays an important role in plant stress resistance. Thus, it is more feasible to increase plant stress resistance at the molecular level. In addition, it is undesirable for fresh fruits and crops to contain fungicidal residues 4. However, the risk of fungi developing fungicidal resistance limits the use of such treatments 3. Traditionally, this pathogen is controlled using fungicidal treatments. It infects cash crops, such as tomatoes and petunias, and causes approximately 15–40% of fruit and flower postharvest deterioration 2.
This fungus infects more than 200 dicotyledonous plants, as well as some monocots 1.
CREATIVE DMG ,PDS SERIES
It is a necrotizing pathogen that destroys host cells with a series of toxic molecules and through the plant’s own defense mechanisms. MITEs appear to be the main sources of 24-nt siRNAs that regulate gene expression through the RNA-directed DNA methylation pathway.īotrytis cinerea is the second most common plant fungal pathogen. We also found that MITEs play a dominant role in controlling DNA methylation levels. Virus-induced gene silencing of MnMET1 enhanced the expression of mulberry-resistance genes, thereby increasing the plant’s resistance to B. DNA methylation inhibitors reduced resistance gene methylation levels and enhanced mulberry resistance, suggesting that the hypomethylation of resistance genes affects mulberry resistance to B. Compared with the former, the latter showed decreased mCG and mCHG levels and increased mCHH levels. Here, we present single-base maps of the DNA methylomes of mulberry ( Morus notabilis) leaves that were subjected to a mock treatment or inoculation with Botrytis cinerea. However, the dynamic changes in DNA methylation in woody plants and their correlations with pathogenic responses are not fully understood. DNA methylation has been proposed to regulate plant stress resistance.
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