Heterotrimeric G protein are involved in the regulation of multiple agronomic traits and stress tolerance in rice

Abstract

Background: The heterotrimeric G protein complex, consisting of Gα, Gβ, and Gγ subunits, are conserved signal transduction mechanism in eukaryotes. Recent molecular researches had demonstrated that G protein signaling participates in the regulation of yield related traits. However, the effects of G protein genes on yield components and stress tolerance are not well characterized. Results: In this study, we generated heterotrimeric G protein mutants in rice using CRISPR/Cas9 (Clustered Regularly Interspaced Short Palindromic Repeats) gene-editing technology. The effects of heterotrimeric G proteins on the regulation of yield components and stress tolerance were investigated. The mutants of gs3 and dep1 generated preferable agronomic traits compared to the wild-type, whereas the mutants of rga1 showed an extreme dwarf phenotype, which led to a dramatic decrease in grain production. The mutants showed improved stress tolerance, especially under salinity treatment. We found four putative extra-large G proteins (PXLG)1-4 that also participate in the regulation of yield components and stress tolerance. A yeast two hybrid showed that the RGB1 might interact with PXLG2 but not with PXLG1, PXLG3 or PXLG4. Conclusion: These findings will not only improve our understanding of the repertoire of heterotrimeric G proteins in rice but also contribute to the application of heterotrimeric G proteins in rice breeding.

Novel Mutant Alleles Reveal a Role of the Extra-Large G Protein in Rice Grain Filling, Panicle Architecture, Plant Growth, and Disease Resistance

“…In the presence of sodium chloride, Arabidopsis the xlg123 triple null mutant had reduced leaf growth (Urano et al, 2016). Based on this report and an earlier study, our results provide solid evidence that XLG2 independently and in combination with XLG4 promotes salt resistance in rice (Urano et al, 2016;Cui et al, 2020).…”

“…When treated with rice blast spores as described in section "Materials and Methods, " Osxlg1-2 and Osxlg2-5 had significantly more lesions than the WT (Figure 5G). Null mutations in individual OsXLG genes did not confer a reduction in plant height at the juvenile stage (35 days) compared to its landrace NIP consistent with the alleles described by Cui et al (2020) (Figures 5D,E). In contrast, substantial morphological differences were observed between the WT (NIP) and combinatorial Osxlg mutants (Figure 5).…”

CRISPR/Cas: A powerful tool for gene function study and crop improvement

“…Knockdown and knockout of ARF4 transcription factor gene improved the water usage efficiency in tomato and allow the editing plants more tolerance to salinity and osmotic stress [100] . CRISPR/Cas-generated mutants of G protein genes gs3 and dep1 enhanced rice tolerance to various abiotic stresses, especially for salinity stress [101] . Knockout of ppa6 gene enhanced rice tolerance to alkaline stress [102] .…”

“…In rice, CRISPR/Cas9-edited variants at the 3′-end of OsLOGL5′s coding sequence (CDS) significantly increased grain yield under drought and low nitrogen treatment as well as well-watered and normal nitrogen control condition, this increase was consistence at multiple geographical locations [119] . Knockout of G protein genes gs3 and dep1 allowed rice to grow more preferable agronomic traits, including grain size and number per panicle [101] . This suggests that CRISPR/Cas genome editing is becoming a new approach for precision breeding for improving crop yield.…”

CRISPR/Cas: a Nobel Prize award-winning precise genome editing technology for gene therapy and crop improvement

“…Knock-out of the G protein genes, gs3 and dep1 , significantly improved rice tolerance to different abiotic stresses, including drought, chilling, and salinity stresses. Under salinity treatment, all tested genome-edited lines showed enhanced tolerance compared to the controls ( Cui et al, 2020 ). Abiotic stresses induced aberrant expression of many transcription factors and non-coding RNAs that play important roles in the plant's response to these environmental stresses.…”