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Biology subjects

Hung, F.-Y.

Publications and source records attributed to Hung, F.-Y..

4 recordsLinked to original sources

Prolonged cold exposure enhances regeneration potential in Arabidopsis

Prolonged cold exposure over winter impacts plant growth and development but its role beyond flowering regulation remains underexplored. In this study, we show that extended cold enhances regenerative capacity, promoting both callus formation and shoot regeneration in Arabidopsis. This enhancement is mediated by the cold-induced AP2/ERF transcription factors C-REPEAT/DRE-BINDING FACTOR 1 (CBF1), CBF2 and CBF3 which interact with the histone acetyltransferase HISTONE ACETYLTRANSFERASE OF THE GNAT FAMILY 1 (HAG1). The CBFs recruit HAG1 to the loci of key regeneration regulators, such as WUSCHEL-RELATED HOMEOBOX 5 (WOX5), to promote their expression via histone acetylation. Our findings thus uncover an epigenetic mechanism by which prolonged cold primes plants for enhanced regeneration, highlighting how environmental cues influence developmental plasticity in plants.

plant biology↗

WIND1 controls cell fate transition through histone acetylation and deacetylation during somatic embryogenesis

Regeneration involves large-scale transcriptional reprogramming to drive cell identity transitions. These transcriptional changes are tightly coupled with chromatin remodelling but molecular mechanisms that coordinate these changes remain unclear. Here we show that WOUND INDUCED DEDIFFERENTIATION 1 (WIND1) transcription factor promotes somatic embryogenesis by repressing pre-existing cell fate and activating new cell identity programmes. WIND1 interacts with histone deacetylase HISTONE DEACETYLASE 9 (HDA9) and histone acetyltransferase complex component HOMOLOG OF YEAST ADA1 2a (ADA2a) via conserved N-terminal domain. These interactions enable WIND1 to mediate both H3K27 deacetylation and acetylation at distinct target loci, leading to repression of shoot identity genes such as AINTEGUMENTA (ANT) and activation of embryogenesis regulators including LEAFY COTYLEDON 2 (LEC2). Our findings identify WIND1 as a bifunctional chromatin regulator that integrates opposing histone acetylation dynamics to coordinate transcriptional reprogramming. This mechanism provides a molecular framework for how a transcription factor directs complex cell fate transitions during regeneration

plant biology↗

The HOMEODOMAIN-Like protein HDL mediates chromatin organization and rewires leaf epidermal patterning

The Arabidopsis leaf epidermis is comprised of trichomes, pavement cells, and stomata, originating from versatile precursor cells capable of dividing or differentiating to create unique epidermal patterns. The mechanism governing these transitions and the maintenance of cell heterogeneity remains unclear. In this study, we identified a novel homeodomain-like superfamily protein, HDL, localized in chromocenters and playing a role in chromatin organization. HDL interacts with histone deacetylase 6 (HDA6) and methyltransferases, indicating its function in modulating chromatin accessibility. In hdl mutants, we observed moderately increased chromatin accessibility in the promoter region of protein-coding genes, along with reduced stomatal density and elevated trichome numbers on leaf surfaces. Corresponding to these phenotypes, stomatal-related gene expression decreased, while a transcriptional reporter for GLABRA2, a trichome initiation gene, exhibited higher and more variable expression levels. These findings highlight how HDL-mediated chromatin organization influences epidermal cell fate by modulating gene expression and enhancing cell heterogeneity within the leaf epidermis. One Sentence SummaryA homeodomain-like protein functions with histone modifiers to regulate chromatin and influence cell fate decisions.

plant biology↗

Arabidopsis histone H3 lysine 9 methyltransferases KYP/SUVH5/6 are involved in leaf development by interacting with AS1-AS2 to repress KNAT1 and KNAT2

Arabidopsis KRYPTONITE/SUPPRESSOR OF VARIEGATION 3-9 HOMOLOG 4 (KYP/SUVH4), SUVH5 and SUVH6 are H3K9 methyltransferases and they are redundantly involved in silencing of transposable elements (TEs). A recent study indicated that KYP/SUVH5/6 can directly interact with the histone deacetylase HDA6 to synergistically regulate TE expression. However, the function of KYP/SUVH5/6 in plant development is still unclear. The ASYMMETRIC LEAVES1 (AS1) and AS2 form a transcription complex, which is involved in leaf development by repressing the homeobox genes KNOTTED-LIKE FROM ARABIDOPSIS THALIANA 1 (KNAT1) and KNAT2. In this study, we found that KYP and SUVH5/6 directly interact with AS1-AS2 to repress KNAT1 and KNAT2 by altering histone H3 acetylation and H3K9 dimethylation levels. In addition, KYP can directly target on the promoters of KNAT1 and KNAT2, and the binding of KYP is dependent on AS1. Furthermore, the genome-wide occupancy profile of KYP indicated that KYP is enriched in the promoter regions of coding genes, and the binding of KYP is positively correlated with that of AS1 and HDA6. Together, these results indicate that Arabidopsis H3K9 methyltransferases KYP/SUVH5/6 are involved in leaf development by interacting with AS1-AS2 to alter histone H3 acetylation and H3K9 dimethylation from the KNAT1 and KNAT2 loci.

plant biology↗