Biology subjects

Loreto, F.

Publications and source records attributed to Loreto, F..

4 recordsLinked to original sources

bioRxiv2025

The transcriptional mechanism behind Mimosa pudica leaf-folding in response to mechanical disturbance

Mimosa pudica is a plant known for its ability to fold leaves in response to mechanical disturbances, which serves as a visible phenotypic stress marker. Leaf folding occurs with a response timing and intensity that varies depending on the stimulus. This adaptive behavior may function as a defense mechanism, helping plant resist herbivores and environmental stressors. However, the molecular and genetic mechanisms that are involved in leaf folding are still not totally understood. In this study, the gene regulatory networks underlying M. pudica leaf closure following single and multiple mechanical disturbances (whole pot drops) were investigated. Chlorophyll fluorescence was measured as fast phenotypic indicator of transient or permanent photochemical damage, and transcriptional responses were measured to identify the key genes regulating phenotypic changes after single or multiple drops. A progressive reduction of the quantum yield of photosystem 2 revealed a lower electron transport rate in leaves subjected to one or more drops, which may indicate the onset of energy shortage, perhaps caused by low ATP availability, limiting both leaf movement and photosynthesis. The transcriptomic profiles revealed larger differences when plants were subjected to multiple drops than to a single drop, with respect to unstressed controls. Interestingly, following a single drop, the majority of up-regulated genes were associated with the flavonoid biosynthetic pathway. After multiple drops, however, genes associated with biotic and abiotic stress resistance pathways were predominantly up-regulated. These results provide a basis for developing a gene regulatory network model of stress-induced movements in M. pudica leaves, which may help design sustainable strategies of plant stress defense. Main ConclusionsRepeated stress in Mimosa pudica reduces photosystem efficiency, alters gene expression, shifting from flavonoid biosynthesis to stress resistance pathways, offering insights for sustainable plant stress defense strategies.

plant biology↗

bioRxiv2024

The effect of constitutive root isoprene emission on root phenotype and physiology under control and salt stress conditions

ABSTRACTIsoprene, a volatile hydrocarbon, is typically emitted from the leaves and other aboveground plant organs; isoprene emission from roots is not well studied. Given its well-known function in plant growth and defense aboveground, isoprene may also be involved in shaping root physiology to resist belowground stress. We used isoprene-emitting transgenic lines (IE) and a non-emitting empty vector and/or wild type lines (NE) of Arabidopsis to elucidate the roles of isoprene in root physiology and salt stress resistance. We assessed root phenotype and metabolic changes, hormone biosynthesis and signaling, and stress-responses under normal and saline conditions of IE and NE lines. We also analyzed the root transcriptome in the presence or absence of salt stress. IE lines emitted isoprene from roots, which was associated with higher primary root growth, root biomass, and root/shoot biomass ratio under both control and salt stress conditions. Transcriptome data indicated that isoprene altered the expression of key genes involved in hormone metabolism and plant responses to stress factors. Our findings reveal that root constitutive isoprene emission sustains root growth also under salinity by regulating and/or priming hormone biosynthesis and signaling mechanisms, amino acids biosynthesis, and expression of key genes relevant to salt stress defense.

plant biology↗

bioRxiv2021

On the capacity of putative plant odorant-binding proteins to bind volatile plant isoprenoids

Plants use odors not only to recruit other organisms for symbioses, but to talk to each other. Volatile organic compounds (VOCs) from "emitting" plants inform the "receiving" (listening) plants of impending stresses or simply of their presence. However, the receptors that allow receivers to perceive the volatile cue are elusive. Most likely, plants (as animals) have odorant bind proteins (OBPs), and in fact few OBPs are known to bind "stress-induced" plant VOCs. We investigated whether OBPs may bind volatile constitutive and stress-induced isoprenoids, the most emitted plant VOCs, with well-established roles in plant communication. First, we performed a data base search that generated a list of candidate plant OBPs. Second, we investigated in silico the ability of the identified candidate plant OBPs to bind VOCs by molecular simulation experiments. Our results show that monoterpenes can bind the same OBPs that were described to bind other stress-induced VOCs. Whereas, the constitutive hemiterpene isoprene does not bind any investigated OBP and may not have an info-chemical role. We conclude that, as for animal, plant OBPs may bind different VOCs. Despite being generalist and not specialized, plant OBPs may play an important role in allowing plants to eavesdrop messages sent by neighboring plants.

plant biology↗

bioRxiv2018

Impact of high phosphorous and sodium on productivity and stress tolerance of Arundo donax plants

Arundo donax L. is an invasive species recently employed for biomass production that emits large amounts of isoprene, a volatile compound having important defensive role. Here, the potential of A. donax to grow in degraded soils, characterized by poor fertility, eutrophication and/or salinization, has been evaluated at morphological, biochemical and transcriptional level. Our results highlight sensitivity of A. donax to P deficiency. Moreover, we show that A. donax response to salt stress (high sodium, Na+), which impaired plant performance causing detrimental effects on leaf cells ultrastructure, is characterized by enhanced biosynthesis of antioxidant carotenoids and sucrose. Differently from Na+, high phosphorous (P) supply did not hamper photosynthesis although it affected carbon metabolism through reduction of starch content and by lowering isoprene emission. In particular, we revealed on salt-stress leaves that high P enhanced the expression of genes involved in abiotic stress tolerance, but further increased diffusive limitations to photosynthesis and slowed-down sugar turnover without modifying isoprene emission. Therefore, despite limiting productivity, high P improved A. donax tolerance to salinity by favouring the accumulation of carbohydrates that protect cells and increase osmotic potential, and by stimulating the synthesis of antioxidants that improves photo-protection and avoids excessive accumulation of reactive oxygen species.\n\nHighlightsArundo donax is sensitive to elevated salinity. High phosphorous supply to salt-stressed A. donax enhances transcriptomic changesthat induce the onset of physiological mechanisms of stress tolerance but limits productivity.

physiology↗