Natural variation in the ORL4 promoter regulates rice leaf rolling to modulate leaf architecture and yield.
Wang X, Xu B, Hu Q, Zhao Y, Zhang Q
Summary
PubMedScientists identified a gene variant that controls how rice leaves roll, and found that editing this variant in elite cultivars significantly increases crop yields by improving leaf architecture and light capture for photosynthesis.
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Key Findings
Genome-wide association study of 802 rice accessions identified 32 loci associated with leaf rolling; ORL4 characterized as a key regulatory gene through CRISPR knockout studies
A single promoter variant (Chr04_19562737-C/T) in ORL4 modulates leaf rolling by altering binding of transcription factor ROC8, with ORL4C allele carriers showing adaxially rolled leaves and ORL4T carriers showing abaxially rolled leaves
Promoter editing of ORL4 in elite cultivar 'Shennong 89-366' generated lines with enhanced leaf rolling and achieved significant yield increases in field trials
Original Abstract
Rice (Oryza sativa L.) leaf rolling enhances canopy architecture and photosynthetic efficiency, thereby improving yield potential. Through genome-wide association studies (GWAS) of 802 Xian and Geng rice accessions, we identified 32 loci associated with the leaf rolling index (LRI) and characterized OUTWARD ROLLED LEAF 4 (ORL4) as a regulatory gene from natural germplasm. CRISPR/Cas9-mediated knockout of ORL4 resulted in abaxially rolled leaves, driven by excessive bulliform cell proliferation and disrupted vascular patterning. A promoter variant (Chr04_19562737-C/T) modulates ORL4 expression by altering the binding affinity of the transcription factor RICE OUTERMOST CELL-SPECIFIC 8 (ROC8). Carriers of the ORL4C allele exhibit stronger ROC8 binding, higher ORL4 expression, and adaxially rolled or flat leaves; ORL4T carriers show the opposite phenotype. ORL4 forms a ternary complex with ROC8 and TOPLESS-RELATED PROTEIN 2(TPL2) to suppress ABAXIALLY CURLED LEAF 1(ACL1), a positive regulator of bulliform cell differentiation. Evolutionary analyses indicated that the ORL4C and ORL4T alleles originated from O. nivara and O. rufipogon, with ORL4C favored in Geng and ORL4T in Xian during domestication. Promoter editing of ORL4 in the elite cultivar 'Shennong 89-366' generated lines with enhanced LRI, achieving a significant yield increase in field trials. This study elucidates the genetic and molecular basis of leaf rolling and provides a promising strategy for rice yield improvement via precise promoter editing.
This connects to 9 other discoveries — 1 species, 3 topics, 5 related articles
Species Mentioned
Rice is a cereal grain and in its domesticated form is the staple food of over half of the world's population, particularly in Asia and Africa. Rice is the seed of the grass species Oryza sativa —or, much less commonly, Oryza glaberrima. Asian rice was domesticated in China some 13,500 to 8,200 y...
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