A clock regulatory module is required for salt tolerance and control of heading date in rice

Abstract

The circadian clock plays multiple roles in plant stress responses and developmental transition phases. Nevertheless, the underlying molecular mechanisms and individual clock components that coordinately regulate important agronomic traits of rice such as salt tolerance and heading date remain to be elucidated. Here, we identify a rice ternary repressive protein complex composed of OsELF4a, OsELF3‐1 and OsLUX, which was designated as OsEC1 in analogy to a similar complex in Arabidopsis. OsELF4a physically interacts with OsELF3‐1 and OsELF3‐2 in nucleus, whilst OsELF3‐1 rather than OsELF3‐2 strongly interacts with OsLUX, a Myb‐domain containing transcriptional factor. Phenotypic analyses show a role for this complex in heading and salt tolerance. The loss‐of‐function mutants of OsEC1 exhibit lower survival rate under salt stress and late heading date. Transcriptomic profiling together with biochemical assays identified the GIGANTEA homologue OsGI as a direct transcriptional target of OsEC1. Notably, the osgi‐101 mutant, generated by CRISPR/Cas9, is salt tolerant and exhibits early heading date in long day conditions. Together, our findings characterized a transcriptional module in rice composed by the OsEC1 repressing OsGI, which links the circadian clock with salt tolerance and control of heading date.

Bifunctional regulators of photoperiodic flowering in short day plant rice

“…A null mutant of OsGI by CRISPR/Cas9 method (cv. Nipponbare) flowered about 25 days earlier and confirmed this conclusion only in LD ( Wang et al., 2021a ). Therefore, OsGI might act upstream and control flowering in the same direction as Hd1 ( Figure 5A ).…”

Engineering drought and salinity tolerance traits in crops through CRISPR-mediated genome editing: Targets, tools, challenges, and perspectives

“…Examples of CRISPR-mediated targeting of kinase and phosphatase genes include FLN2 in rice ( Chen et al., 2020 ), BBS1 in rice ( Zeng et al., 2018 ), and ITPK1 in barley ( Vlčko and Ohnoutková, 2020 ); the edited plants showed salt-responsive phenotypes with reduced tolerance. Apart from TFs or kinases, other salt-stress-responsive factors have been studied using CRISPR tools; examples include MIR528 in rice ( Zhou et al., 2017 ), RBOHD in pumpkin ( Huang et al., 2019 ), NCA1a / OsNCA1b in rice ( Liu et al., 2019 ), SAUR41 in Arabidopsis ( Qiu et al., 2020a , 2020b ), the ACQOS gene cluster in Arabidopsis ( Kim et al., 2021 ), BG3 in rice ( Yin et al., 2020 ), three ELF4 homologs in rice ( Wang et al., 2021b ), HAG1 in hexaploid wheat ( Zheng et al., 2021 ), and HVP10 in barley ( Fu et al., 2021 ).…”

Molecular tools, potential frontiers for enhancing salinity tolerance in rice: A critical review and future prospective

“…CRISPR/Cas9 mutated the OsEC1 to investigate its role under salinity stress. The osgi-101 mutant created by CRISPR/Cas9 is salt tolerant and showed an early heading date under salinity stress ( Wang et al, 2021 ). Likewise, OsSPL10 also plays a key role in salinity tolerance in rice.…”