A homologous gene of OsREL2/ASP1, ASP-LSL regulates pleiotropic phenotype including long sterile lemma in rice

• Published in: BMC plant biology 2021-08, Vol.21 (1), p.1-390, Article 390
• Main Authors: Wu, Tingkai, Ali, Asif, Wang, Jinhao, Song, Jiahe, Fang, Yongqiong, Zhou, Tingting, Luo, Yi, Zhang, Hongyu, Chen, Xiaoqiong, Liao, Yongxiang, Liu, Yutong, Xu, Peizhou, Wu, Xianjun
• Format: Article
• Language: English
• Subjects: Aberrant spikelet; Agricultural production; Amino acid substitution; Amino acids; Analysis; Cell size; Chromosome 8; Cloning; CRISPR; Crop yield; Cultivars; Dwarfism; Fertility; Gene cloning; Gene mapping; Gene mutations; Genes; Genetic analysis; Genetic aspects; Genotype & phenotype; Grain; Homology; Identification and classification; Localization; Long sterile lemma; Morphology; Mutants; Mutation; Phenotype; Phenotypes; Phylogeny; Physiological aspects; Pleiotropic phenotype; Proteins; Relative expression; Rice; Seeds; Sorghum; Tillers; Transcription factors; Varieties
• ISSN: 1471-2229; 1471-2229
• DOI: 10.1186/s12870-021-03163-7

Panicle is a harvesting organ of rice, and its morphology and development are closely associated with grain yield. The current study was carried on a mutant screened through an EMS (ethyl-methane sulphonate) mutagenized population of a Japonica cultivar Kitaake (WT). A mutant, named as asp-lsl (aberrant spikelet-long sterile lemma), showed a significant decrease in plant height, number of tillers, thousand-grains weight, seed setting rate, spikelet length, kernel length and effective number of grains per panicle as compared to WT. Asp-lsl showed a pleiotropic phenotype coupled with the obvious presence of a long sterile lemma. Cross-sections of lemma showed an increase in the cell volume rather than the number of cells. Genetic segregation analysis revealed its phenotypic trait is controlled by a single recessive nuclear gene. Primary and fine mapping indicated that candidate gene controlling the phenotype of asp-lsl was located in an interval of 212 kb on the short arm of chromosome 8 between RM22445 and RM22453. Further sequencing and indels markers analysis revealed LOC_Os08g06480 harbors a single base substitution (G[right arrow]A), resulting in a change of 521st amino acid(Gly[right arrow]Glu. The homology comparison and phylogenetic tree analysis revealed mutation was occurred in a highly conserved domain and had a high degree of similarity in Arabidopsis, corn, and sorghum. The CRISPR/Cas9 mutant line of ASP-LSL produced a similar phenotype as that of asp-lsl. Subcellular localization of ASP-LSL revealed that its protein is localized in the nucleus. Relative expression analysis revealed ASP-LSL was preferentially expressed in panicle, stem, and leaves. The endogenous contents of GA, CTK, and IAA were found significantly decreased in asp-lsl as compared to WT. Current study presents the novel phenotype of asp-lsl and also validate the previously reported function of OsREL2 (ROMOSA ENHANCER LOCI2), / ASP1(ABERRANT SPIKELET AND PANICLE 1).