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Rice SUMO protease Overly Tolerant to Salt 1 targets the transcription factor, Osb ZIP 23 to promote drought tolerance in rice
Author(s) -
Srivastava Anjil Kumar,
Zhang Cunjin,
Caine Robert S,
Gray Julie,
Sadanandom Ari
Publication year - 2017
Publication title -
the plant journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.058
H-Index - 269
eISSN - 1365-313X
pISSN - 0960-7412
DOI - 10.1111/tpj.13739
Subject(s) - proteases , protease , transcription factor , drought tolerance , transgene , gene expression , microbiology and biotechnology , genetically modified crops , gene , chemistry , biochemistry , biology , enzyme , botany
Summary Conjugation of SUMO (Small Ubiquitin‐like Modifier) protein to cellular targets is emerging as a very influential protein modification system. Once covalently bound, SUMO conjugation can change the stability or functionality of its cognate target proteins. SUMO protease can rapidly reverse SUMO conjugation making this modification system highly dynamic. A major factor in the variation of SUMO ‐target function is the balance between the conjugated/de‐conjugated forms. The mechanistic role of these regulatory SUMO proteases in mediating stress responses has not been defined in any crops. In this study, we reveal the role of the SUMO protease, Os OTS 1 in mediating tolerance to drought in rice. Os OTS 1 depleted transgenic plants accumulate more ABA and exhibit more productive agronomic traits during drought while Os OTS 1 overexpressing lines are drought sensitive but ABA insensitive. Drought and ABA treatment stimulates the degradation of Os OTS 1 protein indicating that SUMO conjugation is an important response to drought stress in rice achieved through down‐regulation of OTS 1/2 activity. We reveal that Os OTS 1 SUMO protease directly targets the ABA and drought responsive transcription factor Osb ZIP 23 for de‐ SUMO ylation affecting its stability. Os OTS ‐ RNA i lines show increased abundance of Osb ZIP 23 and increased drought responsive gene expression while Os OTS 1 overexpressing lines show reduced levels of Osb ZIP 23 leading to suppressed drought responsive gene expression. Our data reveal a mechanism in which rice plants govern ABA ‐dependant drought responsive gene expression by controlling the stability of Osb ZIP 23 by SUMO conjugation through manipulating specific SUMO protease levels.