Biology subjects

La Monaca, N.

Publications and source records attributed to La Monaca, N..

3 recordsLinked to original sources

bioRxiv2025

A BBX-HY5 photomorphogenic module induces anthocyanin synthesis in purple tomato fruits

Over the last decades, the search for novel nutraceutical foods led to the development of several anthocyanin enriched crops, with the purple tomato being one of the most prominent examples. In non-GM purple tomato, anthocyanin biosynthesis in fruits is conferred by the introgression of specific alleles of Anthocyanin fruit (Aft) and atroviolacea (atv) genes, which allow the pigmentation of the epicarp under optimal environmental conditions. Light induces anthocyanin synthesis through ELONGATED HYPOCOTYL 5 (HY5), whose levels are in turn controlled by CONSTITUTIVE PHOTOMORPHOGENIC 1 (COP1)-targeted destabilization. In recent years, light-related HY5-independent factors have been object of research. In this work, we have identified two novel transcription factors, belonging to the BBX protein family, modulating anthocyanin synthesis in purple tomato fruits at different stages of the pathway, including transcriptional and post-translational levels, and showing both HY5-dependent and independent functions. Our results contribute to expanding the knowledge on the light-induced regulation of anthocyanin synthesis in tomato and may serve for the development of novel anthocyanin enriched lines able to overcome the threat posed by non-optimal light conditions.

plant biology↗

bioRxiv2025

Hydrogen sulfide modulates plant hypoxic responses through the persulfidation of Plant Cysteine Oxidases

Hydrogen sulfide (H2S) is a gaseous molecule historically regarded as toxic. Nevertheless, increasing evidence has brought to light important physiological roles in both animals and plants. In plants, H2S is involved in environmental and developmental responses, such as stomatal closure and seed germination, and in tolerance mechanisms to different stress conditions like salinity, drought and waterlogging. In this study, we report a function of H2S as a modulator of hypoxic responses in Arabidopsis thaliana. A combination of biochemical and genetic evidence demonstrates that H2S inhibits the activity of Plant Cysteine Oxidases, the molecular sensors of oxygen, through protein persulfidation to modulate hypoxia-associated responses. Furthermore, we show that H2S physiology contributes to responses to low oxygen, as disturbing H2S production impaired activation of hypoxia-responsive genes and submergence tolerance. Overall, this work introduces H2S as signalling modulator in plant hypoxic responses and adds a regulatory layer to the plant oxygen-sensing mechanism.

plant biology↗

bioRxiv2025

Severe Fe deficiency promotes hypoxia inducible responses in Arabidopsis thaliana

In plants, Fe homeostasis and O2 metabolism are strictly related, indeed several Fe-requiring enzymes catalyze reactions that also involve oxygen, as a reagent, product, entry or end point of the metabolic pathway in which the enzyme takes part. Oxygen sensing itself relies on Fe-dependent enzymes, the Plant cysteine oxidase (PCO) family of 2-OG independent thiol dioxygenases. PCOs are responsible for the degradation of ERFVII ethylene-responsive factors through a proteasomal N-degron pathway that connects hypoxia-inducible responses to the stabilization of the ERFVII transcription factors. Here, we investigated the interplay between low oxygen and Fe-deficiency stresses in A. thaliana. We used plants expressing a genetically encoded reporter of ERFVII protein stability and measured the expression of anaerobic genes to infer PCO activity in vivo. Our results highlight that Fe deprivation can elicit hypoxia-like responses depending on its severity. To test the involvement the ERFVII factors further, we examined the response of a pentuple erfVII mutant to Fe-deficiency stress, individually or combined with low oxygen. Our data indicate that the ERFVIIs might take part to the acclimation to chronic Fe deficiency by acting as positive regulators of starvation-responsive genes. Moreover, our results suggest that the ERFVIIs fine-tune nutrient mobilization to the shoots of submerged plants growing on moderately Fe-deficient substrates. This work expands the known functions of the ERFVII factors and provides new information to understand plant responses to combined environmental stresses.

plant biology↗