Biology subjects

Ezquer, I.

Publications and source records attributed to Ezquer, I..

3 recordsLinked to original sources

bioRxiv2025

CLPC2 plays specific roles in CLP complex-mediated regulation of growth, photosynthesis, embryogenesis and response to growth-promoting microbial compounds

In Arabidopsis, exposure to growth-promoting microbial volatile compounds (VCs) enhances CLPC2 levels. This chaperone forms part of the CLP protease complex, which ensures the correct functioning of essential processes in plastids. Previous studies indicated considerable functional redundancy of CLPC2 with its dominant paralogue CLPC1. However, the function and action mechanism of CLPC2 still remain unknown. Here we found that CLPC2-lacking clpc2-2 mutants were unresponsive to microbial VCs, whereas clpc1-1 knockout mutants exhibited a WT-like response to VCs when grown on sucrose-containing medium. Unlike clpc1-1, clpc2-2 plants presented a fully functional photosystem II and lower than WT stomatal conductance. Furthermore, clpc2-2 plants, but not clpc1-1 plants, produced wrinkled seeds with delayed embryonic development and reduced postgerminative establishment rates that resembled those of mutants lacking P and R components of the CLP proteolytic core. Proteomic analyses revealed that knocking out of CLPC2 enhanced the levels of chloroplastic proteins that are essential for growth, embryo development and seedling establishment. These changes differed from those promoted by the lack of CLPC1, but partially resembled those promoted by CLPPR core inactivation. Nearly 40% of the proteins differentially accumulated by the lack of CLPC2 were VC-responsive. Notably, 35S promoter-driven CLPC2 expression promoted changes in the proteome similar to those promoted by the lack of CLPC1. Collectively, our findings highlighted contrasting functional and molecular specificities for CLPC1 and CLPC2, and provided strong evidence that CLPC2 plays specific roles in CLP complex-mediated regulation of plant growth, photosynthesis, embryogenesis, postgerminative seedling establishment and microbial VC responsiveness.

plant biology↗

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

Impact of mutations in the HEADING DATE 1 gene on transcription and cell wall composition of rice

Plants utilize environmental information to modify their developmental trajectories for optimal survival and reproduction. Over a century ago, day length (photoperiod) was identified as a major factor influencing developmental transitions, particularly the shift from vegetative to reproductive growth. In rice, exposure to day lengths shorter than a critical threshold accelerates flowering, while longer days inhibit this process. This response is mediated by HEADING DATE 1 (Hd1), a zinc finger transcription factor that is central in the photoperiodic flowering network. Hd1 acts as a repressor of flowering under long days but functions as a promoter of flowering under short days. However, the transcriptional organization of this dual function is still not fully understood. In this study, we utilized RNA-Seq to analyze the transcriptome of hd1 mutants under both long and short day conditions. We identified genes involved in the phenylpropanoid pathway that are deregulated under long days in the mutant. Quantitative profiling of cell wall components and abiotic stress assays suggest that Hd1 is involved in processes considered unrelated to flowering control. This indicates that day length perception and responses are intertwined with physiological processes beyond flowering.

plant biology↗