The canonical RdDM pathway mediates the control of seed germination timing under salinity ($) (Plant J.)

The canonical RdDM pathway mediates the control of seed germination timing under salinity ($)

Epigenetic regulation can ensure that plant developmental programs and stress responses are tightly coordinated so that environmental changes do not compromise plant fitness. One of the mechanisms to achieve this is through RNA-directed DNA Methylation (RdDM), which is known to participate in several abiotic and biotic stress responses. In this research, Palomar and colleagues test the relative importance of RdDM in the germination of A. thaliana under high salinity conditions. Mutants for the core genes of the RdDM pathway had slower germination in saline conditions than the wild type, suggesting this mechanism is essential for plant responses to this stress. A detailed analysis of the dynamic of one of the core proteins –ARGONAUTE 4 (AGO4)– showed that its accumulation was temporally and spatially altered under high salinity. For instance, Whole-Genome Bisulfite Sequencing revealed that AGO4 modulates the methylation of genes that regulate seed germination and dormancy, such as EIN3 BINDING F-BOX1 and NAC4. Given this, the authors discuss that RdDM modulates seed germination in a stress context. As a result, this study expands our current knowledge about the role of the RdDM pathway in plant responses to abiotic stress in the earlier stages of their development. (Summary by Carlos A. Ordóñez-Parra @caordonezparra) Plant J. 10.1111/tpj.15064