Call Prefix : PR-T

Call Suffix : 2024

Call Cutter : T - AgTe 7

Location : SEARCA Library

Format : Printed

Publisher : National Taiwan University (NTU)

Publication Date : 2024

Publication Place : Taipei City, Taiwan

Summary : Pattern-triggered immunity (PTI) and induced systemic resistance (ISR) are broad-spectrum plant defenses against microbial infection and involve multiple regulatory pathways. Root-colonized microbes, including the beneficial fungus Piriformospora indica and the pathogenic bacterium Ralstonia solanacearum, can manipulate plant defense responses. Epigenetic regulation, including histone acetylation, is known to modulate plant-microbe interactions; however, information regarding epigenetic regulations involved in plant interactions with root-associated microbes is almost undetermined. Our previous studies showed that the symbiosis with P. indica enhances plant ISR to distinct pathogens in tomato via regulating phytohormones signaling pathways in roots and shoots. This study aimed to further decipher the epigenetic regulation in plant interactions with root-associated microbes by studying the roles of Arabidopsis thaliana histone deacetylase 6 (AtHDA6) and AtHDA15, and their tomato orthologs SlHDA3 and SIHDA8 respectively, in establishing plant root PTI, symbioses with P. indica and P. indica-induced ISR against leaf pathogen Pectobacterium carotovorum subsp. carotovorum. The results showed that flg22, an R. solanacearum mutant defective in the type III secretion system, and cell wall extract of P. indica effectively elicit PTI responses, including callose deposition, ROS burst and marker gene expression, in Arabidopsis roots. In addition, colonization of P. indica in Arabidopsis roots promoted ISR to defend against P. carotovorum subsp. carotovorum. Furthermore, the transcriptional expression of AtHDAJ 5, but not that of AtHDA6 can be modulated by elicitors. Characterization of transgenic Arabidopsis plants with altered expression levels of AtHDA6 and AtHDA15 showed that they play differential roles in PTI-related callose deposition, the symbiosis with P. indica and defense against P. carotovorum subsp. carotovorum. Moreover, characterization of SlHDA3-overexpressing tomato plants revealed that SlHDA3 has similar roles with AtHDA6 in these functions. However, SlHDA8 overexpression did not cause obvious changes on these phenotypes. These results together point out the differential HDAs-mediated epigenetic regulations of plant root PTI, the symbiosis with P. indica and defense against P. carotovorum subsp. carotovorum. These results and further future studies are expected to enrich important new insights that may facilitate future work on plant defense research and crop disease control.