TY - JOUR
T1 - The tomato U-box type E3 ligase PUB13 acts with group III ubiquitin E2 enzymes to modulate FLS2-mediated immune signaling
AU - Zhou, Bangjun
AU - Zeng, Lirong
N1 - Funding Information:
This work was supported in part by the University of Nebraska– Lincoln start-up fund to LZ, the U.S. Department of Agriculture National Institute of Food and Agriculture (Grant No. 2012-67014-19449 to LZ), and the National Science Foundation (Grants No. IOS-1460221 and No. IOS-1645659 to LZ).
Funding Information:
This work was supported in part by the University of Nebraska– Lincoln start-up fund to LZ, the U.S. Department of Agriculture National Institute of Food and Agriculture (Grant No. 2012-67014-19449 to LZ), and the National Science Foundation (Grants No. IOS-1460221 and No. IOS-1645659 to LZ). We thank James R. Alfano for sharing the fluorescence microscope for callose diposition assay, Jonathan D. Jones for
Publisher Copyright:
© 2018 Zhou and Zeng.
PY - 2018/5/8
Y1 - 2018/5/8
N2 - In Arabidopsis and rice, the ubiquitin ligase PUB13-mediated protein degradation plays a significant role in plant pattern-triggered immunity (PTI) and flowering time control. The Arabidopsis PUB13 has been shown to attenuate the pattern recognition receptor FLS2-mediated immune signaling by ubiquitinating FLS2 and consequently promoting its degradation by the 26S proteasome. Nevertheless, the cognate ubiquitin-conjugating enzymes (E2) with which PUB13 acts to modulate FLS2-mediated PTI are unknown. To address this question, we investigate here the tomato (Solanum lycopersicum) homolog of PUB13, SlPUB13 by utilizing the recently characterized complete set of tomato E2s. Of the 13 groups of tomato E2s, only members in group III are found to interact and act with SlPUB13. Knocking-down of the group III E2 genes enhances callose deposition and induction of the RbohB gene in the immunity-associated, early oxidative burst after flg22 treatment. The group III E2s are also found to work with SlPUB13 to ubiquitinate FLS2 in vitro and are required for PUB13-mediated degradation of FLS2 in vivo upon flg22 treatment, suggesting an essential role for group III E2s in the modulation of FLS2-mediated immune signaling by PUB13. Additionally, another immunity-associated E3, NtCMPG1 is shown to also work specifically with members of group III E2 in the in vitro ubiquitination assay, which implies the group III E2 enzymes may cooperate with many E3 ligases to regulate different aspects of PTI. Taken together, these data corroborate the notion that group III E2 enzymes play an important role in PTI and build a foundation for further functional and mechanistic characterization of tomato PUB13.
AB - In Arabidopsis and rice, the ubiquitin ligase PUB13-mediated protein degradation plays a significant role in plant pattern-triggered immunity (PTI) and flowering time control. The Arabidopsis PUB13 has been shown to attenuate the pattern recognition receptor FLS2-mediated immune signaling by ubiquitinating FLS2 and consequently promoting its degradation by the 26S proteasome. Nevertheless, the cognate ubiquitin-conjugating enzymes (E2) with which PUB13 acts to modulate FLS2-mediated PTI are unknown. To address this question, we investigate here the tomato (Solanum lycopersicum) homolog of PUB13, SlPUB13 by utilizing the recently characterized complete set of tomato E2s. Of the 13 groups of tomato E2s, only members in group III are found to interact and act with SlPUB13. Knocking-down of the group III E2 genes enhances callose deposition and induction of the RbohB gene in the immunity-associated, early oxidative burst after flg22 treatment. The group III E2s are also found to work with SlPUB13 to ubiquitinate FLS2 in vitro and are required for PUB13-mediated degradation of FLS2 in vivo upon flg22 treatment, suggesting an essential role for group III E2s in the modulation of FLS2-mediated immune signaling by PUB13. Additionally, another immunity-associated E3, NtCMPG1 is shown to also work specifically with members of group III E2 in the in vitro ubiquitination assay, which implies the group III E2 enzymes may cooperate with many E3 ligases to regulate different aspects of PTI. Taken together, these data corroborate the notion that group III E2 enzymes play an important role in PTI and build a foundation for further functional and mechanistic characterization of tomato PUB13.
KW - FLS2
KW - Immune signaling
KW - PUB13
KW - Pattern-triggered immunity
KW - Tomato
KW - U-box
KW - Ubiquitin
KW - Ubiquitin-conjugating enzyme (E2)
UR - http://www.scopus.com/inward/record.url?scp=85046888830&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85046888830&partnerID=8YFLogxK
U2 - 10.3389/fpls.2018.00615
DO - 10.3389/fpls.2018.00615
M3 - Article
C2 - 29868071
AN - SCOPUS:85046888830
SN - 1664-462X
VL - 9
JO - Frontiers in Plant Science
JF - Frontiers in Plant Science
M1 - 615
ER -