Disruption of the OsWRKY71 Transcription Factor Gene Results in Early Rice Seed Germination Under Normal and Cold Stress Conditions

Authors

Santiago Bataller, University of Nevada, Las VegasFollow
James A. Davis, University of Nevada, Las Vegas
Lingkun Gu, University of Nevada, Las Vegas
Sophia Baca, University of Nevada, Las Vegas
Gaelan Chen, University of Nevada, Las Vegas
Azeem Majid, University of Nevada, Las Vegas
Anne J. Villacastin, University of Nevada, Las Vegas
Dylan Barth, University of Nevada, Las Vegas
Mira V. Han, University of Nevada, Las Vegas
Paul J. Rushton, University of Nevada, Las Vegas
Qingxi J. Shen, University of Nevada, Las VegasFollow

Document Type

Article

Publication Date

11-18-2024

Publication Title

BMC Plant Biology

Volume

24

First page number:

1

Last page number:

19

Abstract

Background

Early seed germination in crops can confer a competitive advantage against weeds and reduce the time to maturation and harvest. WRKY transcription factors regulate many aspects of plant development including seed dormancy and germination. Both positive and negative regulators of seed germination have been reported in many plants such as rice and Arabidopsis. Using a transient expression system, we previously demonstrated that OsWRKY71 is a negative regulator of gibberellin (GA) signaling in aleurone cells and likely forms a “repressosome” complex with other transcriptional repressors. Hence, it has the potential to impact seed germination properties.

Results

In this study, we demonstrate that OsWRKY71, a Group IIa WRKY gene, appeared at the same time as seed-bearing plants. Rice mutants lacking OsWRKY71 have seeds and embryos that germinate earlier than wildtype controls. In oswrky71 aleurone layers, α-amylase activity was hypersensitive to stimulation by GA3 and hyposensitive to inhibition by abscisic acid (ABA). Early germination in oswrky71 intact seeds was also hyposensitive to ABA. Transcriptomic profiling during embryo germination and early post-germination growth demonstrates that OsWRKY71 influences the expression of 9–17% of genes in dry and imbibing embryos. Compared to wildtype embryos, the mutant transcriptomes have large temporal shifts at 4, 8 and 12 h after imbibition (HAI). Importantly, many genes involved in the ABA-dependent inhibition of seed germination were downregulated in oswrky71-1. This mutant also displayed altered expression of multiple ABA receptors (OsPYLs/RCARs) that control ABA signaling and the VP1-SDR4-DOG1L branch of ABA signaling that promotes seed dormancy. Association studies reveal an OsWRKY71-containing quantitative trait locus involved in low-temperature seed germinability, qLTG-2. Indeed, oswrky71 seeds germinated early at 15 °C.

Conclusions

Rice Group-IIa WRKY transcription factor OsWRKY71 is a master regulator of germination that influences the expression of 9–17% of genes in dry and imbibing embryos. It is also most likely the primary candidate of low-temperature seed germinability QTL, qLTG-2. We propose that knockouts of OsWRKY71 can generate rice varieties with improved germination properties under normal or low-temperature conditions.

Keywords

Seed germination; WRKY transcription factors; RNA-sequencing; Oryza sativa, Embryos; Cold temperature; Quantitative trait loci (QTL)

Disciplines

Environmental Microbiology and Microbial Ecology | Genetics | Genomics

File Format

PDF

File Size

5600 KB

Language

English

Rights

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Creative Commons License

This work is licensed under a Creative Commons Attribution 4.0 License.

Repository Citation

Bataller, S., Davis, J. A., Gu, L., Baca, S., Chen, G., Majid, A., Villacastin, A. J., Barth, D., Han, M. V., Rushton, P. J., Shen, Q. J. (2024). Disruption of the OsWRKY71 Transcription Factor Gene Results in Early Rice Seed Germination Under Normal and Cold Stress Conditions. BMC Plant Biology, 24 1-19.
http://dx.doi.org/10.1186/s12870-024-05808-9