Abstract
Main conclusion
We generated drooping leaf rice mutants by CRISPR/Cas and identified two novel alleles with specific editing that allow underpinning of the function of the DL protein domain towards midrib and carpel formations.
Abstract
The DROOPING LEAF (DL) gene plays an essential role in regulating midrib formation and carpel specification in rice and other grass species, but the specific function of DL protein domains in different developmental processes is unclear. Analysis of different dl mutant alleles will allow dissecting the function of DL. Here, we generated Nipponbare rice dl mutants using CRISPR/Cas gene editing and identified two novel dl alleles with different effects on midrib formation and carpel development. Phenotypic and genotypic analysis of T0 and segregated T1 edited lines showed that while dl-51S allele (a 3 bp deletion and a serine deletion at position 51) reduces midrib sizes and produces normal carpels, the dl-50LS allele (a 6 bp deletion and a leucine-serine deletion at position 50–51) causes the lack of midribs and abnormal stigma. This result indicates that the 51-serine is important for midrib formation and the 50-leucine is essential for midrib and carpel development. These dl mutant alleles contribute to the DL gene functional analysis and to gain insights into possible modifications of leaf architecture of rice and other grass species.



Data availability
The datasets used and/or analyzed during the current study are available from the corresponding author on reasonable request.
Abbreviations
- ASV:
-
Adaxial small vascular bundle
- CRISPR:
-
Clustered regularly interspaced short palindromic repeats
- DL:
-
Drooping leaf
- sgRNA:
-
Single guide RNA
References
Abiko M, Ohmori Y, Hirano HY (2008) Genome-wide expression profiling and identification of genes under the control of the DROOPING LEAF gene during midrib development in rice. Genes Genet Syst 83(3):237–244
Ikeda T, Tanaka W, Mikami M, Endo M, Hirano HY (2015) Generation of artificial drooping leaf mutants by CRISPR-Cas9 technology in rice. Genes Genet Syst 90(4):231–235
Li H, Liang W, Hu Y, Zhu L, Yin C, Xu J, Dreni L, Kater MM, Zhang D (2011a) Rice MADS6 interacts with the floral homeotic genes SUPERWOMAN1, MADS3, MADS58, MADS13, and DROOPING LEAF in specifying floral organ identities and meristem fate. Plant Cell 23(7):2536–2552
Li H, Liang W, Yin C, Zhu L, Zhang D (2011b) Genetic interaction of OsMADS3, DROOPING LEAF, and OsMADS13 in specifying rice floral organ identities and meristem determinacy. Plant Physiol 156(1):263–274
Li M, Li X, Zhou Z, Wu P, Fang M, Pan X, Lin Q, Luo W, Wu G, Li H (2016) Reassessment of the four yield-related genes Gn1a, DEP1, GS3, and IPA1 in rice using a CRISPR/Cas9 system. Front Plant Sci 7:377
Mathan J, Bhattacharya J, Ranjan A (2016) Enhancing crop yield by optimizing plant developmental features. Development 143(18):3283–3294
Nagasawa N, Miyoshi M, Sano Y, Satoh H, Hirano H, Sakai H, Nagato Y (2003) SUPERWOMAN1 and DROOPING LEAF genes control floral organ identity in rice. Development 130(4):705–718
Ohmori Y, Abiko M, Horibata A, Hirano HY (2008) A transposon, Ping, is integrated into intron 4 of the DROOPING LEAF gene of rice, weakly reducing its expression and causing a mild drooping leaf phenotype. Plant Cell Physiol 49(8):1176–1184
Ohmori Y, Toriba T, Nakamura H, Ichikawa H, Hirano HY (2011) Temporal and spatial regulation of DROOPING LEAF gene expression that promotes midrib formation in rice. Plant J 65(1):77–86
Rogers SO, Bendich AJ (1994) Extraction of total cellular DNA from plants, algae and fungi. In: Schilerpoort RA, Gelvin SB (eds) Plant molecular biology manual. Kluwer Academic Publishers, Dordrecht, pp 183–190
Strable J, Wallace JG, Unger-Wallace E, Briggs S, Bradbury PJ, Buckler ES, Vollbrecht E (2017) Maize YABBY genes drooping leaf1 and drooping leaf2 regulate plant architecture. Plant Cell 29(7):1622–1641
Toki S (1997) Rapid and efficient Agrobacterium-mediated transformation in rice. Plant Mol Biol Rep 15(1):16–21
Toriba T, Hirano HY (2014) The DROOPING LEAF and OsETTIN2 genes promote awn development in rice. Plant J 77(4):616–626
Wang B, Smith SM, Li J (2018) Genetic regulation of shoot architecture. Annu Rev Plant Biol 69:437–468
Xie K, Minkenberg B, Yang Y (2015) Boosting CRISPR/Cas9 multiplex editing capability with the endogenous tRNA-processing system. Proc Natl Acad Sci USA 112(11):3570–3575
Yamaguchi T, Nagasawa N, Kawasaki S, Matsuoka M, Nagato Y, Hirano HY (2004) The YABBY gene DROOPING LEAF regulates carpel specification and midrib development in Oryza sativa. Plant Cell 16(2):500–509
Zhang Y, Pribil M, Palmgren M, Gao C (2020) A CRISPR way for accelerating improvement of food crops. Nat Food 1(4):200–205
Zhao M, Tang S, Zhang H, He M, Liu J, Zhi H, Sui Y, Liu X, Jia G, Zhao Z, Yan J (2020) DROOPY LEAF1 controls leaf architecture by orchestrating early brassinosteroid signaling. Proc Natl Acad Sci USA 117(35):21766–21774
Acknowledgements
This work was supported by the Office of the Ministry of Higher Education, Science, Research and Innovation; and the Thailand Science Research and Innovation through the Kasetsart University Reinventing University Program 2021 and Thailand Science Research and Innovation (TSRI) through Maejo University annual research Grant 2021 (MJ.1-65-008). SV was supported by National Research Council of Thailand: NRCT5-RSA63002-02.
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Janthabut, T., Tristianto, C., Sakulkoo, J. et al. Effects of CRISPR/Cas9 generated drooping leaf (dl) alleles on midrib and carpel formations in Oryza sativa Nipponbare. Planta 256, 61 (2022). https://doi.org/10.1007/s00425-022-03973-5
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DOI: https://doi.org/10.1007/s00425-022-03973-5