Trends in Plant Science
SpotlightBoosting Rice Yield by Fine-Tuning SPL Gene Expression
Section snippets
SPL Genes Play Major Roles in Plant Development
IPA1 encodes Oryza sativa (Os)SPL14, a member of the SQUAMOSA PROMOTER BINDING PROTEIN (SBP)-like (SPL) family of plant-specific transcription factors that all contain a highly conserved DNA-binding domain (SBP domain) of ∼76 amino acids in length [4]. Since the identification of the first two members AmSBP1 and AmSBP2 in snapdragon (Antirrhinum majus), SPL genes have been found in nearly all plant species including algae and moss [4].
It is now known that some SPL genes are regulated by
SPL Genes Have Multiple Roles in Rice Yield
In 2010, two groups from China and Japan independently reported the function of OsSPL14 identified by quantitative trait locus (QTL) cloning, and named the locus IPA1 and WFP (Wealthy Farmer’s Panicle), respectively. The variants of OsSPL14 dampened tiller branching, but increased panicle branching and grain weight together with stronger culms 6, 7. Functional analysis showed that IPA1 had a point mutation in the recognition site for miR156/157/529, while WFP changed epigenetic modification in
Exploring the Expression Dosage Effects of SPL Genes for Crop Improvement
Wang et al. proposed that fine-tuning SPL gene expression may provide a strategy for increasing rice productivity in breeding [5]. The available data from functional tests of SPL genes are in agreement with the idea of fine-tuning strategy (Figure 1B–E).
For example, compared to the previously reported IPA1 allele (renamed ipa1-1D) [6], ipa1-2D is weaker in promoting OsSPL14 expression. However, such weaker expression results in plants with an optimal combination of tiller number and panicle
Concluding Remarks
While the functions of other SPL genes still need to be tested, the findings so far have important implications in breeding applications in rice. The desirable alleles can be used directly to improve rice yield by traditional crossing approach, with or without marker-assisted selection. Gene-editing technology such as CRISPR/Cas9 can be used to modify the regulatory regions or miRNA recognition sites of SPL genes to modify their expression patterns/levels to create novel mutations for desirable
Acknowledgments
L.W. is supported by a grant from the China Postdoctoral Science Foundation (2016M590699); Q.Z. is supported by a grant from the National Key Research and Development Program (2016YFD0100903).
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2022, Biotechnology AdvancesCitation Excerpt :SPL genes regulate plant architecture and grain size in rice. Fine-tuning corresponding SPL expression provides a strategy for modulating grain size, shape, and yield (Wang and Zhang, 2017). GW8 encodes OsSPL16.