Splicing regulation by RS2Z36 controls ovary patterning and fruit growth in tomato
Authors: Vraggalas, S., Rosenkranz, R. R., Keller, M., Perez-Perez, Y., Bachiri, S., Zehl, K., Bold, J., Simm, S., Ghatak, A., Weckwerth, W., Afjehi-Sadat, L., Chaturvedi, P., Testillano, P. S., Mueller-McNicoll, M., Zarnack, K., Fragkostefanakis, S.
The study identifies the serine/arginine-rich splicing factor RS2Z36 as a key regulator of ovary patterning and early fruit morphology in tomato, with loss‑of‑function mutants producing smaller, ellipsoid fruits and elongated pericarp cells. RNA‑seq and proteomic analyses reveal widespread alternative splicing and altered protein abundance, including novel splice‑variant peptides, while mutant pericarps show increased deposition of LM6‑detected arabinan and AGP epitopes.
The study functionally characterizes a conserved structured RNA motif (45ABC) in Arabidopsis RBP45 pre‑mRNAs, showing that its sequence and pairing elements mediate a negative auto‑ and cross‑regulatory feedback loop through alternative splicing that produces unproductive isoforms and reduces RBP45 expression. Transcriptome‑wide splicing analysis and phenotypic assessment of rbp45 mutants reveal that RBP45B plays a dominant role and that proper regulation of this motif is essential for root growth and flowering time.
The study examined DNA methylation dynamics in Arabidopsis thaliana shoots and roots under heat, phosphate deficiency, and combined stress using whole-genome bisulfite sequencing, small RNA‑seq, and RNA‑seq. Distinct stress‑specific methylation patterns were identified, with heat and combined stress causing CHH hypomethylation, phosphate deficiency causing hyper‑ and hypomethylation in shoots and roots respectively, and the combined stress exhibiting a unique signature independent of additive effects. Methylation changes were concentrated in transposable elements and regulatory regions, implicating RdDM and CMT2 pathways and suggesting a role in chromatin accessibility rather than direct transcriptional control.
The study examines how ectopic accumulation of methionine in Arabidopsis thaliana leaves, driven by a deregulated AtCGS transgene under a seed‑specific promoter, reshapes metabolism, gene expression, and DNA methylation. High‑methionine lines exhibit increased amino acids and sugars, activation of stress‑hormone pathways, and reduced expression of DNA methyltransferases, while low‑methionine lines show heightened non‑CG methylation without major transcriptional changes. Integrated transcriptomic and methylomic analyses reveal a feedback loop linking sulfur‑carbon metabolism, stress adaptation, and epigenetic regulation.
The study mapped the cis‑regulatory landscape of the winter rapeseed cultivar Express617, identifying thousands of novel regulatory elements and characterizing super‑enhancers that are asymmetrically enriched in the Cn subgenome of Brassica napus. An in‑silico pipeline combining population‑level expression data and machine‑learning models revealed that many SE‑associated genes are expressed above predicted levels, and structural variants disrupting SEs lead to reduced gene expression, highlighting their functional importance for gene regulation and breeding.
The study integrated 16 Arabidopsis thaliana whole‑genome bisulfite sequencing datasets from 13 stress experiments using a unified bioinformatic pipeline to map common and stress‑specific DNA methylation changes. Differentially methylated regions varied by stress type and methylation context, with CG DMRs enriched in gene bodies and CHG/CHH DMRs in transposable elements, some of which overlapped loci prone to stable epimutations. Gene ontology and TE enrichment analyses highlighted shared stress pathways and suggest environmental stress can generate heritable epigenetic variation.
A large-scale proteomic study in Arabidopsis thaliana identified over 32,000 isoform-specific peptides, confirming that alternative splicing, particularly intron retention, produces translated protein isoforms. Integrated proteogenomic analysis, SUPPA classification, and AlphaFold modeling revealed structural impacts and a non-linear regulation of transcript and protein abundance, with mutant phenotypes linking splicing to growth, chlorophyll content, and anthocyanin accumulation.
Drought-Induced Epigenetic Memory in the cambium of Poplar Trees persists and primes future stress responses
Authors: DUPLAN, A., FENG, Y. Q., LASKAR, G., CAI, B. D., SEGURA, V., DELAUNAY, A., LE JAN, I., DAVIAUD, C., TOUMI, A., LAURANS, F., SOW, M. D., ROGIER, O., POURSAT, P., DURUFLE, H., JORGE, V., SANCHEZ, L., COCHARD, H., ALLONA, I., TOST, J., FICHOT, R., MAURY, S.
The study examined short‑term and transannual drought memory in cambium tissues of two Populus genotypes and four epitypes with modified DNA‑methylation machinery, revealing persistent hormone, transcript, and methylation changes one week after stress relief. Trees previously stressed in Year 1 displayed distinct physiological and molecular responses to a second drought in Year 2, indicating long‑term memory linked to stable CG‑context DNA methylation, with genotype‑dependent differences in plasticity and stability. These findings position the cambium as a reservoir for epigenetic stress memory and suggest exploitable epigenetic variation for tree breeding under drought.
The study investigated metabolic responses of kale (Brassica oleracea) grown under simulated microgravity using a 2-D clinostat versus normal gravity conditions. LC‑MS data were analyzed with multivariate tools such as PCA and volcano plots to identify gravity‑related metabolic adaptations and potential molecular markers for spaceflight crop health.
Using genome‑wide association studies in Arabidopsis thaliana, the authors identified the chromatin‑associated protein CDCA7 as a trans‑regulator that specifically controls CG methylation (mCG) and TE silencing. CDCA7 and its paralog CDCA7β bind the remodeler DDM1, modulating its activity without broadly affecting non‑CG methylation or histone variant deposition, and natural variation in CDCA7 regulatory sequences correlates with local ecological adaptation.