The chromatin remodeler ZmCHB101 impacts alternative splicing contexts in response to osmotic stress.

KEY MESSAGE: Maize SWI3-type chromatin remodeler impacts alternative splicing contexts in response to osmotic stress by altering nucleosome density and affecting transcriptional elongation rate. Alternative splicing (AS) is commonly found in higher eukaryotes and is an important posttranscriptional regulatory mechanism to generate transcript diversity. AS has been widely accepted as playing essential roles in different biological processes including growth, development, signal transduction and responses to biotic and abiotic stresses in plants. However, whether and how chromatin remodeling complex functions in AS in plant under osmotic stress remains unknown. Here, we show that a maize SWI3D protein, ZmCHB101, impacts AS contexts in response to osmotic stress. Genome-wide analysis of mRNA contexts in response to osmotic stress using ZmCHB101-RNAi lines reveals that ZmCHB101 impacts alternative splicing contexts of a subset of osmotic stress-responsive genes. Intriguingly, ZmCHB101-mediated regulation of gene expression and AS is largely uncoupled, pointing to diverse molecular functions of ZmCHB101 in transcriptional and posttranscriptional regulation. We further found ZmCHB101 impacts the alternative splicing contexts by influencing alteration of chromatin and histone modification status as well as transcriptional elongation rates mediated by RNA polymerase II. Taken together, our findings suggest a novel insight of how plant chromatin remodeling complex impacts AS under osmotic stress .