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Abstract Glucosinolates (GSLs) are defensive secondary metabolites produced by Brassicaceae species in response to abiotic and biotic stresses. The biosynthesis of GSL compounds and the expression of GSL-related genes are highly modulated by endogenous signals (i.e. circadian clocks) and environmental cues, such as temperature, light, and pathogens. However, the detailed mechanism by which light signaling influences GSL metabolism remains poorly understood. In this study, we found that a light-signaling factor, ELONGATED HYPOCOTYL 5 (HY5), was involved in the regulation of GSL content under light conditions in Arabidopsis (Arabidopsis thaliana). In hy5-215 mutants, the transcript levels of GSL pathway genes were substantially upregulated compared with those in wild-type (WT) plants. The content of GSL compounds was also substantially increased in hy5-215 mutants, whereas 35S::HY5-GFP/hy5-215 transgenic lines exhibited comparable levels of GSL-related transcripts and GSL content to those in WT plants. HY5 physically interacts with HISTONE DEACETYLASE9 and binds to the proximal promoter region of MYB29 and IMD1 to suppress aliphatic GSL biosynthetic processes. These results demonstrate that HY5 suppresses GSL accumulation during the daytime, thus properly modulating GSL content daily in Arabidopsis plants.
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This content will become publicly available on October 31, 2026
Convergence and constraint in glucosinolate evolution across the Brassicaceae
Abstract Diversity in plant specialized metabolites plays critical roles in plant–environment interactions. In longer evolutionary scales, e.g. between families or orders, this diversity arises from whole-genome and tandem duplication events. Less is known about the evolutionary patterns that shape chemical diversity at shorter scales, e.g. within a family. Utilizing the aliphatic glucosinolate pathway, we explored how the genes encoding the terminal structural modification enzyme GSL-OH evolved across the Brassicaceae and the genomic processes that control presence–absence variation of its products (R)-2-hydroxy-but-3-enyl and (S)-2-hydroxy-but-3-enyl glucosinolate. We implemented a phylo-functional approach to functionally validate GSL-OH orthologs across the Brassicaceae and used that information to map the genomic origin and trajectory of the locus. This uncovered a complex mechanism involving at least 3 ancestral loci with extensive gene loss across all species, creating unequal retention across the phylogenetic relationships. Convergent evolution in enantiomeric specificity was observed, where several independent species had tandem duplicates that diverged toward producing the R or S enantiomers. To explore potential biological differences between the enantiomers, we performed Trichoplusia ni larval choice assays and tested resistance against Botrytis cinerea in a detached leaf assay. We found that plants with the S-enantiomer were more susceptible to B. cinerea infection than to T. ni larval herbivory, while plants with the R-enantiomer seemed more susceptible to T. ni larval herbivory when compared to B. cinerea. Ultimately, we observed recurrent GSL-OH loss, uncovered a complex origin story for the gene, and measured the bioactivity of the enzyme's metabolic products.
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- PAR ID:
- 10651089
- Publisher / Repository:
- The Plant Cell
- Date Published:
- Journal Name:
- The Plant Cell
- Volume:
- 37
- Issue:
- 11
- ISSN:
- 1040-4651
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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