Biology subjects

Gaspar Litholdo, C.

Publications and source records attributed to Gaspar Litholdo, C..

2 recordsLinked to original sources

bioRxiv2024

An Omics approach on Marchantia polymorpha single FERONIA and MARIS homologs confirms links between cell wall integrity and abscisic acid

Plant cells are surrounded by an extracellular cell wall that shields them from their abiotic and biotic environment. To coordinate their growth with their cell wall status, plant cells have developed cell wall integrity (CWI) mechanisms, at the center of which lies the transmembrane Malectin-like receptor kinase FERONIA (FER). FER controls a myriad of plant developmental processes including sexual reproduction, cell growth and morphogenesis, often intersecting with phytohormones-dependent pathways such as abscisic acid (ABA) signaling or plant immunity. Interestingly, FER together with its downstream receptor-like cytoplasmic kinase MARIS (MRI) was shown to similarly control root hair and rhizoid integrity in the vascular angiosperm Arabidopsis and the early diverging bryophyte Marchantia polymorpha, respectively. Here, we performed comparative transcriptomics and proteomics on the M. polymorpha mutant plants, Mpfer-1 and Mpmri-1, and their corresponding wild-type accessions Tak-1 and Tak-2. Large and significant overlaps were observed between differentially expressed genes and differentially abundant proteins in both mutants. Our multi-omics approach revealed that MpFER and MpMRI largely cooperate to negatively regulate transcriptional and translational networks, particularly those related to plant defense and ABA responses. Moreover, our phenotypic analyses showed that Mpfer-1 plants are hypersensitive to ABA-dependent growth inhibition, indicating that FERs function of negatively regulating ABA-related growth responses is conserved between bryophytes and vascular plants.

plant biology↗

bioRxiv2024

ECT2 peptide sequences outside the YTH domain regulate its m6A-RNA binding

The m6A epitranscriptomic mark is the most abundant and widespread internal RNA chemical modification, which through the control of RNA acts as an important actor of eukaryote reproduction, growth, morphogenesis and stress response. The main m6A readers constitute a super family of proteins with hundreds of members that share a so-called YTH RNA binding domain. The majority of YTH proteins carry no obvious additional domain except for an Intrinsically Disordered Region (IDR). In Arabidopsis thaliana IDRs are important for the functional specialization among the different YTH proteins, known as Evolutionarily Conserved C-Terminal region, ECT 1 to 12. Here by studying the ECT2 protein and using an in vitro biochemical characterization, we show that full length ECT2 and its YTH domain alone have a distinct ability to bind m6A, conversely to previously characterized YTH readers. We identify peptide regions outside of ECT2 YTH domain, in the N-terminal IDR, that regulate its binding to m6A-methylated RNA. Furthermore, we show that the selectivity of ECT2 binding for m6A is enhanced by a high uridine content within its neighboring sequence, where ECT2 N-terminal IDR is believed to contact the target RNA in vivo. Finally, we also identify small structural elements, located next to ECT2 YTH domain and conserved in a large set of YTH proteins, that enhance its binding to m6A-methylated RNA. We propose from these findings that some of these regulatory regions are not limited to ECT2 or YTH readers of the flowering plants but may be widespread among the eukaryotic YTH readers.

biochemistry↗