The Casparian strip (CS) constitutes a physical diffusion barrier to water and nutrients in plant roots, which is formed by the polar deposition of lignin polymer in the endodermis tissue. The precise pattern of lignin deposition is determined by the scaffolding activity of membrane-bound Casparian Strip domain proteins (CASPs), but little is known of the mechanism(s) directing this process. Here, we demonstrate that Endodermis-specific Receptor-like Kinase 1 (ERK1) and, to a lesser extent, ROP Binding Kinase1 (RBK1) are also involved in regulating CS formation, with the former playing an essential role in lignin deposition as well as in the localization of CASP1.
View Article and Find Full Text PDFAlthough plants are able to withstand a range of environmental conditions, spikes in ambient temperature can impact plant fertility causing reductions in seed yield and notable economic losses. Therefore, understanding the precise molecular mechanisms that underpin plant fertility under environmental constraints is critical to safeguarding future food production. Here, we identified two Argonaute-like proteins whose activities are required to sustain male fertility in maize plants under high temperatures.
View Article and Find Full Text PDFPlants differ from animals in their capability to easily regenerate fertile adult individuals from terminally differentiated cells. This unique developmental plasticity is commonly observed in nature, where many species can reproduce asexually through the ectopic initiation of organogenic or embryogenic developmental programs. While organ-specific epigenetic marks are not passed on during sexual reproduction, the fate of epigenetic marks during asexual reproduction and the implications for clonal progeny remain unclear.
View Article and Find Full Text PDFGenome editing using CRISPR/Cas9 is considered the best instrument for genome engineering in plants. This methodology is based on the nuclease activity of Cas9 that is guided to specific genome sequences by single guide RNAs (sgRNAs) thus enabling researchers to engineer simple mutations or large chromosomal deletions. Current methodologies for targeted genome editing in plants using CRISPR/Cas9 are however largely inefficient, mostly due to low Cas9 activity, variable sgRNA efficiency and low heritability of genetic lesions.
View Article and Find Full Text PDFInducible epigenetic changes in eukaryotes are believed to enable rapid adaptation to environmental fluctuations. We have found distinct regions of the Arabidopsis genome that are susceptible to DNA (de)methylation in response to hyperosmotic stress. The stress-induced epigenetic changes are associated with conditionally heritable adaptive phenotypic stress responses.
View Article and Find Full Text PDFThe elongation phase of the RNA polymerase II (RNAPII) transcription process is dynamic and regulated. Elongator and SUPPRESSOR OF Ty4 (SPT4)/SPT5 are transcript elongation factors that contribute to the regulation of mRNA synthesis by RNA polymerase II in the chromatin context. Recently, the Elongator complex consisting of six subunits and the SPT4/SPT5 heterodimer were isolated from Arabidopsis.
View Article and Find Full Text PDFThe heterodimeric complex SPT4/SPT5 is a transcript elongation factor (TEF) that directly interacts with RNA polymerase II (RNAPII) to regulate messenger RNA synthesis in the chromatin context. We provide biochemical evidence that in Arabidopsis, SPT4 occurs in a complex with SPT5, demonstrating that the SPT4/SPT5 complex is conserved in plants. Each subunit is encoded by two genes SPT4-1/2 and SPT5-1/2.
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