Repressor of jasmonate responses. Unable to associate strongly with COI1 in the presence of jasmonoyl-isoleucine (JA-Ile) and is therefore more resistant to JA-mediated-degradation than other TIFY/JAZ proteins. Repress gene expression through direct recruitment of the corepressor TOPLESS to cognate transcription factors (PubMed:19151223, PubMed:22327740). Interacts with and suppresses RHD6 and RSL1 transcription factor activities to negatively regulate jasmonate-stimulated root hair development (PubMed:31988260). Interacts with TPL and weakly with COI1, but not with AFPH2/NINJA (PubMed:22327740). Interacts with MYC2, MYB21, MYB24, TIFY10A/JAZ1, TIFY10B/JAZ2, TIFY6B/JAZ3, TIFY6A/JAZ4, TIFY11A/JAZ5, TIFY11B/JAZ6, TIFY7/JAZ9, TIFY9/JAZ10 and TIFY3B/JAZ12 (PubMed:19151223, PubMed:19309455, PubMed:21447791, PubMed:22327740). Interacts with RHD6 and RSL1 (PubMed:31988260). (Microbial infection) Interacts with the pathogenic Pseudomonas syringae HopZ1a protein. (Microbial infection) Triggered to degradation by the pathogenic Pseudomonas syringae HopZ1a protein in a COI1-dependent manner, thereby activating host jasmonate signaling. Up-regulated by jasmonate, wounding and herbivory. The jas domain (105-127) lacks the canonical jasmonoyl-isoleucine (JA-Ile) degron LPIARR that strongly interact with COI1 in the presence of JA-Ile in other TIFY/JAZ proteins (PubMed:22327740). The LxLxL-type EAR (ERF-associated amphiphilic repression) motif (9-13) is required for the interaction with the corepressor TOPLESS (PubMed:22327740). The jas domain (105-127) is required for interaction with Pseudomonas syringae HopZ1a (By similarity). (Microbial infection) Acetylated by Pseudomonas syringae HopZ1a. Ubiquitinated. TIFY5A/JAZ8-mediated repression does not require the tify domain, which, in other TIFY/JAZ proteins, recruits the corepressor TOPLESS through the adapter protein AFPH2/NINJA. Belongs to the TIFY/JAZ family.