FLA, which encodes a homolog of UBP, is required for chlorophyll accumulation and development of lemma and palea in rice
FLA, the homolog of ubiquitin-specific protease does not have deubiquitination activity, but it is essential for flower and chloroplast development in rice.
Ubiquitin-specific proteases (UBPs) are widely distributed and highly conserved proteins and are also members of the most important family of deubiquitination enzymes. Although the functions and phylogenies of UBPs from yeast, mammals and Arabidopsis have been widely reported, the functions and evolutionary relationships of UBPs in rice remain unclear. In this study, we characterized the rice flower and leaf color aberrant mutant (fla), which exhibited a variety of developmental defects, including abnormal floral organs and pollen development, and leaf bleaching. We isolated FLA by positional cloning and found that it encodes a homolog of ubiquitin-specific protease. FLA is a ubiquitously expressed gene with the highest expression in floral organs. Subcellular localization analysis indicated that FLA is a cell membrane protein. Through searches of the rice genome database (http://rice.plantbiology.msu.edu), we identified 35 UBP family members in the rice genome. These proteins were grouped into 16 subfamilies based on phylogenetic analysis, and FLA was found to belong to the G8 subfamily. In vitro activity assays revealed that FLA does not have deubiquitination activity. Our data suggest that FLA plays an important role in the development of floral organs and chloroplast in rice, but that this role probably does not involve deubiquitination activity, because FLA does not have an active site and deubiquitination activity.
KeywordsLeaf bleaching Phylogenetic analysis Deubiquitination Oryza sativa L.
Meprin and TRAF homology
Zinc-finger ubiquitin-specific protease
Myeloid, Nervy and DEAF1-type zinc finger
Domain in USPs
This work was supported by National Natural Science Foundation of China (No. 31501287), National Key Research and Development Program of China (2016YFD0100101, 2016YFD0100301), National Science and Technology Support Program of China (2015BAD01B01-1), CAAS Science and Technology Innovation Program, National Infrastructure for Crop Germplasm Resources (NICGR2017-01), Protective Program of Crop Germplasm of China (2017NWB 036-01, 2017NWB036-12-2).
Compliance with ethical standards
Conflict of interest
The authors declare that they have no conflict of interest.
- Kawahara Y, de la Bastide M, Hamilton JP, Kanamori H, McCombie WR, Ouyang S, Schwartz DC, Tanaka T, Wu J, Zhou S, Childs KL, Davidson RM, Lin H, Quesada-Ocampo L, Vaillancourt B, Sakai H, Lee SS, Kim J, Numa H, Itoh T, Buell CR, Matsumoto T (2013) Improvement of the Oryza sativa Nipponbare reference genome using next generation sequence and optical map data. Rice 6:4CrossRefGoogle Scholar
- Rao-Naik C, Chandler JS, McArdle B, Callis J (2000) Ubiquitin-specific proteases from Arabidopsis thaliana: cloning of AtUBP5 and analysis of substrate specificity of AtUBP3, AtUBP4, and AtUBP5 using Escherichia coli in vivo and in vitro assays. Arch Biochem Biophys 379:198–208CrossRefGoogle Scholar
- Zhou H, Zhao J, Yang Y, Chen C, Liu Y, Jin X, Chen L, Li X, Deng XW, Schumaker KS, Guo Y (2012) Ubiquitin-specific protease16 modulates salt tolerance in Arabidopsis by regulating Na(+)/H(+) antiport activity and serine hydroxymethyltransferase stability. Plant Cell 24:5106–5122CrossRefGoogle Scholar
- Zhou J, Zhang Y, Qi JX, Chi YJ, Fan BF, Yu JQ, Chen ZX (2014) E3 ubiquitin ligase CHIP and NBR1-mediated selective autophagy protect additively against proteotoxicity in plant stress responses. PLoS Genet 10(1):e1004116. https://doi.org/10.1371/journal.pgen.1004116 CrossRefPubMedPubMedCentralGoogle Scholar