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Apple SUMO E3 ligase MdSIZ1 facilitates SUMOylation of MdARF8 to regulate lateral root formation
Author(s) -
Zhang ChunLing,
Wang GuiLuan,
Zhang YaLi,
Hu Xing,
Zhou LiJie,
You ChunXiang,
Li YuanYuan,
Hao YuJin
Publication year - 2021
Publication title -
new phytologist
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.742
H-Index - 244
eISSN - 1469-8137
pISSN - 0028-646X
DOI - 10.1111/nph.16978
Subject(s) - sumo protein , arabidopsis , ubiquitin ligase , microbiology and biotechnology , biology , ubiquitin , mutant , immunoprecipitation , root hair , lateral root , arabidopsis thaliana , bimolecular fluorescence complementation , ubiquitin protein ligases , auxin , biochemistry , yeast , gene
Summary Post‐translational modification of proteins mediated by SIZ1, a small ubiquitin‐like modifier (SUMO) E3 ligase, regulates multiple biological processes in plants. However, its role in the regulation of lateral root formation remains unclear. Here, we demonstrate that the apple SUMO E3 ligase MdSIZ1 promotes lateral root formation. Using a yeast‐two‐hybrid (Y2H) system, the auxin response factor MdARF8 was screened out as a protein–protein interaction partner of the SUMO‐conjugating E2 enzyme MdSCE1, indicating that MdARF8 may be a substrate for MdSIZ1. The interaction between MdARF8 and MdSCE1 was confirmed by pull‐down, Y2H and Co‐immunoprecipitation assays. MdSIZ1 enhanced the conjugating enzyme activity of MdSCE1 to form a MdSCE1–MdSIZ1–MdARF8 complex, thereby facilitating SUMO modification. We identified two arginine substitution mutations at K342 and K380 in MdARF8 that blocked MdSIZ1‐mediated SUMOylation, indicating that K342 and K380 are the principal SUMOylation sites of the MdARF8 protein. Moreover, MdARF8 promoted lateral root formation in transgenic apple plants, and the phenotype of reduced lateral roots in the Arabidopsis siz1‐2 mutant was restored in siz1‐2/MdARF8 complementary plants. Our findings reveal an important role for sumoylation in the regulation of lateral root formation in plants.