Linking Specific Chromatin Remodeling to Pathogenic Defenses

The Chromatin Remodeler SPLAYED Regulates Specific Stress Signaling Pathways is a paper authored by Justin W. Walley, Heather C. Rowe, Yanmei Xiao, E. Wassim Chehab, Daniel J. Kliebenstein, Doris Wagner and Katayoon Dehesh. It was published in PLOS Pathogens. Chromatin is a complex which includes proteins, primarily histones, as well as DNA. Access to genes can be determined by a process known as chromatin remodeling. Chromatin remodeling enables the timely expression of genes. The linked paper details the investigation of chromatin remodeling which relates to transcription of proteins needed by the plant Arabidopsis to mount an effective defense against a specific pathogen. Researchers focused particularly on the SPLAYED protein and its role in chromatin remodeling. They found that SPLAYED functions within specified biotic stress signaling networks.

The abstract:

Organisms are continuously exposed to a myriad of environmental stresses. Central to an organism's survival is the ability to mount a robust transcriptional response to the imposed stress. An emerging mechanism of transcriptional control involves dynamic changes in chromatin structure. Alterations in chromatin structure are brought about by a number of different mechanisms, including chromatin modifications, which covalently modify histone proteins; incorporation of histone variants; and chromatin remodeling, which utilizes ATP hydrolysis to alter histone-DNA contacts. While considerable insight into the mechanisms of chromatin remodeling has been gained, the biological role of chromatin remodeling complexes beyond their function as regulators of cellular differentiation and development has remained poorly understood. Here, we provide genetic, biochemical, and biological evidence for the critical role of chromatin remodeling in mediating plant defense against specific biotic stresses. We found that the Arabidopsis SWI/SNF class chromatin remodeling ATPase SPLAYED (SYD) is required for the expression of selected genes downstream of the jasmonate (JA) and ethylene (ET) signaling pathways. SYD is also directly recruited to the promoters of several of these genes. Furthermore, we show that SYD is required for resistance against the necrotrophic pathogen Botrytis cinerea but not the biotrophic pathogen Pseudomonas syringae. These findings demonstrate not only that chromatin remodeling is required for selective pathogen resistance, but also that chromatin remodelers such as SYD can regulate specific pathways within biotic stress signaling networks.