AUTHOR=Li Shijuan , Xu Bingliang , Niu Xiaolei , Lu Xiang , Cheng Jianping , Zhou Meiliang , Hooykaas Paul J. J. 

TITLE=JAZ8 Interacts With VirE3 Attenuating Agrobacterium Mediated Root Tumorigenesis

JOURNAL=Frontiers in Plant Science

VOLUME=12

YEAR=2021

URL=https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2021.685533

DOI=10.3389/fpls.2021.685533

ISSN=1664-462X

ABSTRACT=<p><italic>Agrobacterium tumefaciens</italic> can cause crown gall tumors by transferring both an oncogenic piece of DNA (T-DNA) and several effector proteins into a wide range of host plants. For the translocated effector VirE3 multiple functions have been reported. It acts as a transcription factor in the nucleus binding to the <italic>Arabidopsis thaliana</italic> pBrp TFIIB-like protein to activate the expression of <italic>VBF</italic>, an F-box protein involved in degradation of the VirE2 and VIP1 proteins, facilitating <italic>Agrobacterium</italic>-mediated transformation. Also VirE3 has been found at the plasma membrane, where it could interact with VirE2. Here, we identified AtJAZ8 in a yeast two-hybrid screening with VirE3 as a bait and confirmed the interaction by pull-down and bimolecular fluorescence complementation assays. We also found that the deletion of <italic>virE3</italic> reduced <italic>Agrobacterium</italic> virulence in a root tumor assay. Overexpression of <italic>virE3</italic> in Arabidopsis enhanced tumorigenesis, whereas overexpression of <italic>AtJAZ8</italic> in Arabidopsis significantly decreased the numbers of tumors formed. Further experiments demonstrated that AtJAZ8 inhibited the activity of VirE3 as a plant transcriptional regulator, and overexpression of <italic>AtJAZ8</italic> in Arabidopsis activated <italic>AtPR1</italic> gene expression while it repressed the expression of <italic>AtPDF1.2</italic>. Conversely, overexpression of <italic>virE3</italic> in Arabidopsis suppressed the expression of <italic>AtPR1</italic> whereas activated the expression of <italic>AtPDF1.2</italic>. Our results proposed a novel mechanism of counter defense signaling pathways used by <italic>Agrobacterium</italic>, suggesting that VirE3 and JAZ8 may antagonistically modulate the salicylic acid/jasmonic acid (SA/JA)-mediated plant defense signaling response during <italic>Agrobacterium</italic> infection.</p>