Integrated analysis of ATAC-seq and RNA-seq reveals the TCP-ARF molecular module related to pathogenic process of phytoplasma infection in Paulownia fortunei.

Abstract

BACKGROUND: Witches’ broom is an important disease of the Paulownia fortunei. Understanding the pathogenesis of witches’ broom is a prerequisite for its prevention and control. Phytoplasma is the pathogen of Paulownia witches’ broom. RESULTS: We investigated the changes in chromatin accessibility before and after phytoplasma infection in Paulownia fortunei by analyzing the DNA accessibility (ATAC-seq). In phytoplasma-infected P. fortunei (PFI) compared to healthy samples (PF), the closed regions of chromatin(1187 regions) were three times more than the open regions (352 regions). Fifty one percent of the accessible chromatin regions were overlapped with either H3K27ac or H3K9ac peaks. The closed regions were enriched in the conserved motif TGGGC[CT] that is recognized by the TCP transcription factor family. The closed regions in PFI are intersected with ARF family gene locus. The gene PfARF3 was verified to interact with the PfTCP23 transcription factor. The PfTCP23 was predicted to be interacted with the effector pawb44 in the pathogen of phytoplasma. CONCLUSIONS: The phytoplasma infection in P. fortunei is involved in the chromatin changes of the DNA accessibility and histone modification. The binding regions of TCP23 were found to be changed mostly in the accessibility between PFI and PF. The TCP-ARF module was found to be the possible regulatory module inducing the crinkled leaf trait.