An embryo-derived peptide signal directs endosperm polarity in Arabidopsis .

September 3, 2026| Source: Science (New York, N.Y.)

Angiosperm seed formation requires the coordinated development of the products of double fertilization-the embryo and the endosperm. The endosperm mediates efficient nutrient transfer from surrounding maternal tissues to the developing embryo. This function requires a polarized tissue organization, which manifests as early polar gene expression and polar cellularization dynamics. We show that the receptor kinase HAIKU2 (IKU2) acts in coordination with the transcription factor WRKY10/MINISEED3 (MINI3) to ensure robust endosperm polarity establishment through the activity of the homeodomain transcription factors WUSCHEL-RELATED HOMEOBOX 8 (WOX8) and WOX9. This process depends on egg cell fertilization and is mediated through the peptide PATHOGEN-INDUCED PEPTIDE-LIKE 7 (PIPL7), which acts as a potential IKU2 ligand. Our results reveal how a molecular paracrine dialog between the embryo and endosperm ensures optimal seed developmental coordination.

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PLASTID ENVELOPE ION CHANNELS (PEC1/2) link Ca 2+ and jasmonic acid signaling in plant cells.

Plants constantly encounter adverse environmental interactions. One organelle is particularly specialized in stress signaling and phytohormone synthesis: the plastid. Calcium (Ca 2+ ), a key second messenger, is known to intersect with cellular phytohormone signaling networks. While cytosolic Ca 2+ dynamics have been studied extensively, the physiological relevance of stromal Ca 2+ transients and the identity of channels mediating rapid Ca 2+ flux into plastids remain largely unexplored. In this

Health & MedicineSeptember 28, 2026

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Gram-positive bacteria encode a broad array of ABC transporters that mediate substrate translocation across the cell membrane, with some contributing to their survival under environmental stresses such as antimicrobial exposure. While several of these transporters have been shown to exhibit multidrug efflux activity, the functional roles of many others remain unknown. Here, using an efflux pump screen in the opportunistic human pathogen Streptococcus pneumoniae , we identified a previously uncha

Health & MedicineSeptember 26, 2026

Detection of "hidden" mitotic crossovers by long-read DNA sequencing.

Mitotic crossovers in diploid organisms are usually detected by looking for loss of heterozygosity (LOH) for a marker. Assuming the crossover occurs between two duplicated chromatids, a single reciprocal crossover will result in two recombinant chromatids and two nonrecombinant chromatids. LOH will only be observed when a recombinant chromatid cosegregates with a nonrecombinant chromatid. Cells containing both recombinant chromosomes will not result in LOH. Below, we use long-range DNA sequencin

Health & MedicineSeptember 26, 2026

Amino acid homeostasis by CORVET/HOPS: A metabolic and stress resilience checkpoint for T cells.

Amino acid sufficiency is critical for T cell metabolic reprogramming, yet how T cells maintain amino acid homeostasis remains poorly defined. Here, we identify the CORVET and HOPS (CORVET/HOPS) tethering complexes as essential upstream regulators. In activated T cells, they sustain intracellular amino acid levels by promoting macropinocytosis to acquire extracellular nutrients. This function enables dual signaling outcomes: suppression of the integrated stress response (ISR) and activation of m

Health & MedicineSeptember 25, 2026

Bright monomeric fluorescent protein elite-niRFP704 for two-channel near-infrared STED nanoscopy.

The near-infrared (NIR) spectral region is attractive for live-cell imaging, due to low autofluorescence and reduced phototoxicity. Some phytochrome-derived fluorescent proteins absorb and emit fluorescence in the NIR, but have short fluorescence lifetimes and relatively low quantum yields, requiring higher laser powers thus limiting their usefulness for live-cell superresolution microscopy. Using the bacterial phytochrome miRFP703 as a template, we screened for variants with longer fluorescence