The study investigates the role of the Arabidopsis transcription factor AtMYB93 in sulfur (S) signaling and root development, revealing that AtMYB93 mutants exhibit altered expression of S transport and metabolism genes and increased shoot S levels, while tomato plants overexpressing SlMYB93 show reduced shoot S. Transcriptomic profiling, elemental analysis, and promoter activity assays indicate that AtMYB93 contributes to root responses to S deprivation, though functional redundancy masks clear phenotypic effects on lateral and adventitious root formation.
The study performed transcriptome profiling of Cryptomeria japonica individuals from different geographic origins grown in three common gardens across Japan, assembling 77,212 transcripts guided by the species' genome. Using SNP-based genetic clustering and weighted gene co‑expression network analysis, they identified gene modules whose expression correlated with genetic differentiation, revealing that defense‑related genes are up‑regulated in Pacific‑side populations while terpenoid metabolism genes are higher in Sea‑of‑Japan populations, indicating local adaptation via regulatory changes.
Arabidopsis REM transcription factors and GDE1 shape the DNA methylation landscape through the recruitment of RNA Polymerase IV transcription complexes.
Authors: Wu, Z., Xue, Y., Wang, S., Shih, Y.-H., Zhong, Z., Feng, S., Draper, J., Lu, A., Sha, J., Li, L., Wohlschlegel, J., Wu, K., Jacobsen, S. E.
The study identifies four Arabidopsis REM transcription factors (VDD, VAL, REM12, REM13) that bind specific DNA sequences and, together with GDE1, recruit RNA polymerase IV to produce 24‑nt siRNAs that direct DNA methylation at designated loci. Loss of GDE1 causes Pol IV complexes to relocalize to sites bound by REM8, indicating that REM proteins provide sequence‑specific cues for epigenetic patterning.
The study reveals that a set of REPRODUCTIVE MERISTEM (REM) transcription factors, termed RIMs, are essential for directing RNA‑directed DNA methylation (RdDM) to CLSY3 targets in a sex‑specific manner in Arabidopsis reproductive tissues. Disruption of RIM DNA‑binding domains or their target motifs abolishes RdDM at these loci, demonstrating that genetic cues can guide de novo methylation patterns.
The study generated two allotriploid Brassica hybrids (ArAnCn) to investigate asymmetric subgenome dominance, finding that the Cn subgenome dominates despite the An subgenome showing highest expression levels. Increased density of accessible chromatin regions (ACRs) in the Cn subgenome correlates with dominant gene expression, while changes in CHH methylation and specific RNA‑directed DNA methylation pathway mutants affect subgenome bias.
Assembly and annotation of Solanum dulcamara and Solanum nigrum plant genomes, two nightshades with different susceptibilities to Ralstonia solanacearum
Authors: Franco Ortega, S., James, S. R., Gilbert, L., Hogg, K., Stevens, H., Daff, J., Friman, V. P., Harper, A. L.
The study generated de‑novo genome assemblies for the resistant wild relative Solanum dulcamara and the susceptible Solanum nigrum using a hybrid Oxford Nanopore and Illumina sequencing strategy. Comparative genomic analyses identified auxin‑transport genes and novel pattern recognition receptor orthogroups unique to resistant species, as well as differential gene‑body methylation that may underlie resistance to Ralstonia solanacearum.