Araniti, F. | Search bioRxiv

bioRxiv2025

ARABIDOPSIS Bsister and SEEDSTICK MADS-box transcription factors modulate maternal nutrient flow for seed development in Arabidopsis

Successful seed development in angiosperms depends on the coordinated transport and allocation of sugars from maternal tissues to the developing embryo and endosperm. In Arabidopsis thaliana, ovules function as carbohydrate sink organs, accumulating starch in both gametophytic and sporophytic domains prior to fertilization. This stored starch is later mobilized to support early embryogenesis. Despite extensive knowledge of starch metabolism in photosynthetic tissues, the regulatory mechanisms governing sugar transport in reproductive organs remain poorly understood. Recent studies have identified fertilization-dependent changes in nutrient flow, including callose-mediated modulation of symplastic transport at the phloem unloading site. However, the molecular players orchestrating these transitions are largely unknown. Here, we show that the MIKC MADS domain transcription factors ABS/TT16 and STK play critical roles in regulating maternal nutrient flow during ovule maturation and seed development. We dissect their functional redundancy using omics and genetic approaches, underscoring the importance of different ovule tissues in coordinating sugar transport pathways for post-fertilization development. Our findings reveal a previously underappreciated layer of genetic control over nutrient allocation in reproductive tissues and provide new insights into the metabolic reprogramming required for successful seed formation.

plant biology↗

bioRxiv2024

Ongoing local adaptation to climate change in yarrow (Achillea millefolium L.)

Climate change threatens biodiversity as populations can persist if they migrate or adapt to the rapidly changing conditions of the Anthropocene. However, little is known about the persistence of plant populations under the long-term trends of increasing temperature and drought. We explore whether historical populations of yarrow (Achillea millefolium L.) surveyed in the 1920s have persisted locally or undergone local extinction after 100 years. We resurveyed historical sites spanning a broad climatic gradient (from 1 m to 3,200 m a.s.l.), examined to what extent plant growth signature (height) has changed over time, and analyzed metabolic diversity. Nine out of ten populations persisted locally and showed phenotypic and metabolic differentiation. The only population potentially extirpated is that of the hottest and driest site. Populations from warm sites in coastal and mountain regions had grown taller than 100 years ago. In contrast, populations from dry sites in lowlands and foothills became shorter. Furthermore, we document differentiation in metabolic diversity involving plant defenses and signaling. Ongoing local adaptation is constrained by changing both temperature and precipitation as well as by biotic interactions. Preserving locally adapted populations and metabolic diversity is key for conservation efforts.

evolutionary biology↗