Plant growth and development are governed by selective protein synthesis and degradation. Ubiquitination mediated protein degradation is governed by activating enzyme E1 followed by conjugating enzyme E2 and E3 ligase. Plant Armadillo (ARM) repeat/U-box (PUB) protein family is one of the important classes of E3 ligase. We studied the function of AtPUB2 by loss-of-function (knockout and knock down mutants) and gain-of-function (CaMV 35S promoter driven overexpression lines) approach in Arabidopsis. Under normal growth condition, we observed that loss-of-function mutant plants did not show any significance difference in growth when compared to wild-type possibly due to functional redundancy between PUB2 and PUB4. However, AtPUB2-OE lines exhibits early flowering and improved vegetative growth. Also, AtPUB2-OE seedlings showed sensitive phenotype in the presence of exogenous cytokinin. We found that AtPUB2 expression is induced under oxidative stress. Subcellular localization analysis shows that AtPUB2 is predominantly localized in the nucleus. We performed the phenotypic analysis under oxidative stress condition induced by methyl viologen (MV) and observed that overexpression lines display tolerance to oxidative stress in light and dark conditions. Further, we found less amount of ROS accumulation, enhanced proline accumulation and decreased levels of MDA after MV treatment in AtPUB2-OE lines. PUB2-OE lines showed enhanced oxidative stress marker genes expression. By in-vitro auto-ubiquitination assay, we also show that it possesses the E3 ligase activity. Our findings suggest the possible role of AtPUB2 in plants ability to tolerate oxidative stress by enhancing the activity of antioxidant enzymes, which in turn improves ROS scavenging activity and homeostasis.
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Research Article|
March 14 2023
Overexpression of ARM repeat/U-box containing E3 ligase, PUB2 positively regulates growth and oxidative stress response in Arabidopsis
Lokesh Kumar Saini;
Lokesh Kumar Saini
Delhi University South Campus, New Delhi, India
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Manisha Sharma;
Manisha Sharma
Delhi University South Campus, New Delhi, India
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Barkha Ravi;
Barkha Ravi
Delhi University South Campus, New Delhi, India
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Soma Ghosh;
Soma Ghosh
Delhi University South Campus, New Delhi, India
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Sonam Pahuja;
Sonam Pahuja
Delhi University South Campus, New Delhi, India
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Nidhi Singh;
Nidhi Singh
Delhi University South Campus, New Delhi, India
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Girdhar K. Pandey
Delhi University South Campus, New Delhi, India
* Corresponding Author; email: gkpandey@south.du.ac.in
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Biochem J (2023) BCJ20230026.
Article history
Received:
January 29 2023
Revision Received:
March 08 2023
Accepted:
March 13 2023
Citation
Lokesh Kumar Saini, Manisha Sharma, Barkha Ravi, Soma Ghosh, Sonam Pahuja, Nidhi Singh, Girdhar K. Pandey; Overexpression of ARM repeat/U-box containing E3 ligase, PUB2 positively regulates growth and oxidative stress response in Arabidopsis
. Biochem J 2023; BCJ20230026. doi: https://doi.org/10.1042/BCJ20230026Download citation file:
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