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A sorghum gigantea mutant attenuates florigen gene expression and delays flowering time.

ABSTRACT: GIGANTEA (GI) is a conserved plant-specific gene that modulates a range of environmental responses in multiple plant species, including playing a key role in photoperiodic regulation of flowering time. The C4 grass Sorghum bicolor is an important grain and subsistence crop, animal forage, and cellulosic biofuel feedstock that is tolerant of abiotic stresses and marginal soils. To understand sorghum flowering time regulatory networks, we characterized the sbgi-ems1 nonsense mutant allele of the sorghum GIGANTEA (SbGI) gene from a sequenced M4 EMS-mutagenized BTx623 population. sbgi-ems1 plants flowered later than wild type siblings under both long-day or short-day photoperiods. Delayed flowering in sbgi-ems1 plants accompanied an increase in node number, indicating an extended vegetative growth phase prior to flowering. sbgi-ems1 plants had reduced expression of floral activator genes SbCO and SbEHD1 and downstream FT-like florigen genes SbFT, SbCN8, and SbCN12. Therefore, SbGI plays a role in regulating SbCO and SbEHD1 expression that serves to accelerate flowering. SbGI protein physically interacts with the sorghum FLAVIN-BINDING, KELCH REPEAT, F-BOX1-like (SbFFL) protein, a conserved flowering-associated blue light photoreceptor, and the SbGI-SbFFL interaction is stimulated by blue light. This work demonstrates that SbGI is an activator of sorghum flowering time upstream of florigen genes under short- and long-day photoperiods, likely in association with the activity of the blue light photoreceptor SbFFL. Significance Statement:This study elucidates molecular details of flowering time networks for the adaptable C4 cereal crop Sorghum bicolor, including demonstration of a role for blue light sensing in sorghum GIGANTEA activity. This work validates the utility of a large publicly available sequenced EMS-mutagenized sorghum population to determine gene function.

SUBMITTER: Abdul-Awal SM

PROVIDER: S-EPMC7665845 | biostudies-literature | 2020 Nov

REPOSITORIES: biostudies-literature

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A sorghum gigantea mutant attenuates florigen gene expression and delays flowering time.

Abdul-Awal S M SM Chen Junping J Xin Zhanguo Z Harmon Frank G FG

Plant direct 20201113 11

GIGANTEA (GI) is a conserved plant-specific gene that modulates a range of environmental responses in multiple plant species, including playing a key role in photoperiodic regulation of flowering time. The C4 grass Sorghum bicolor is an important grain and subsistence crop, animal forage, and cellulosic biofuel feedstock that is tolerant of abiotic stresses and marginal soils. To understand sorghum flowering time regulatory networks, we characterized the sbgi-ems1 non ...[more]

PMID: 33210074

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Project description:IntroductionThe APETALA2/ethylene response factor (AP2/ERF) superfamily plays a significant role in regulating plant gene expression in response to growth and development. To date, there have been no studies into whether the ramie AP2/ERF genes are involved in the regulation of flower development.MethodsHere, 84 BnAP2/ERF members were identified from the ramie genome database, and various bioinformatics data on the AP2/ERF gene family, structure, replication, promoters and regulatory networks were analysed. BnAP2-12 was transferred into Arabidopsis through the flower-dipping method.ResultsPhylogenetic analysis classified the 84 BnAP2/ERF members into four subfamilies: AP2 (18), RAV (3), ERF (42), and DREB (21). The functional domain analysis of genes revealed 10 conserved motifs. Genetic mapping localised the 84 members on 14 chromosomes, among which chromosomes 1, 3, 5, and 8 had more members. Collinearity analysis revealed that 43.37% possibly resulted from replication events during the evolution of the ramie genome. Promoter sequence analysis identified classified cis-acting elements associated with plant growth and development, and responses to stress, hormones, and light. Transcriptomic comparison identified 3,635 differentially expressed genes (DEGs) between male and female flowers (1,803 and 1,832 upregulated and downregulated genes, respectively). Kyoto Encyclopaedia of Genes and Genomes pathway analysis categorised DEGs involved in metabolic pathways and biosynthesis of secondary metabolites. Gene Ontology enrichment analysis further identified enriched genes associated with pollen and female gamete formations. Of the 84 BnAP2/ERFs genes, 22 and 8 upregulated and downregulated genes, respectively, were present in female flowers. Co-expression network analysis identified AP2/ERF members associated with flower development, including BnAP2-12. Subcellular localisation analysis showed that the BnAP2-12 protein is localised in the nucleus and cell membrane. Overexpression BnAP2-12 delayed the flowering time of Arabidopsis thaliana.ConclusionThese findings provide insights into the mechanism of ramie flower development.

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A sorghum gigantea mutant attenuates florigen gene expression and delays flowering time.

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A sorghum <i>gigantea</i> mutant attenuates florigen gene expression and delays flowering time.

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