Biology subjects

Reguera, M.

Publications and source records attributed to Reguera, M..

5 recordsLinked to original sources

bioRxiv2025

Root growth promotion by Penicillium melinii: mechanistic insights and agricultural applications

O_LIThis study characterizes Penicillium melinii, an endophytic fungus isolated from Arabidopsis thaliana roots, as a plant growth-promoting fungus with potential use as a model to study root development and as a biostimulant for sustainable agriculture. Although endophytes are known to promote plant growth, the underlying molecular mechanisms often remain poorly understood. Here, we aimed to elucidate how P. melinii enhances root system development and to assess its applicability across different crops. C_LIO_LIPhenotypic assays were conducted in Arabidopsis, quinoa and tomato under in vitro, greenhouse and field conditions. Root architecture and biomass were quantified using image-based phenotyping. Transcriptomic and phytohormone profiling assessed plant responses, and fungal genome sequencing coupled with secretome analysis was used to identify candidate effectors and metabolic traits. C_LIO_LIP. melinii consistently promoted root growth and increased plant biomass across species and environments, both in vitro and in the greenhouse. In tomato field trials, this translated into a significant increase in yield. The fungus colonized root surfaces without vascular penetration and triggered a mild transcriptomic response: early activation of stress-response genes followed by their attenuation and sustained upregulation of auxin-related pathways. Notably, the interaction modulates the SLR-ARF-LBD pathway and the number of pre-branch sites probably through increased auxin signalling in the oscillation zone. Additional hormonal changes were limited and mainly associated with the attenuation of the plant response to microorganisms. C_LIO_LIP. melinii enhances lateral root formation through a subtle molecular and metabolic dialogue with the host plant, underscoring its relevance as a model for studying root developmental plasticity. Its strong and reproducible growth-promoting effect, demonstrated with different fungal strains and under controlled and field conditions, supports its potential as a biostimulant for sustainable crop production. C_LI

plant biology↗

bioRxiv2022

Genotype-dependent responses to long-term water stress in Chenopodium quinoa Willd

Within the current climate context, freshwater resources have become scarce. Agriculture, especially in rain-fed conditions, should deal with the need for increasing yields to contribute to food security under limiting water availability. Exploring underutilized crops such as Chenopodium quinoa (quinoa) has become a unique opportunity as some of these crops possess the ability to tolerate several abiotic stresses, including drought. In line with this, this work aimed at evaluating the genotype-dependent response to drought by comparing the performance of different European-adapted cultivars (F14, F15, F16, and Titicaca). The results show that the cultivars here evaluated presented different mechanisms to cope with long-term water stress, including changes in phenology, morphology, or physiology. Among them, the cultivar F16 might be the most promising genotype to grow under water-limiting conditions as it was able to increase Water Use Efficiency (WUE), reducing the stomatal conductance and keeping CO2 assimilation rates similar to well-watered conditions, maintaining seed yield and increasing harvest index (HI) under water deficit conditions. Furthermore, based on these results, we propose a model in which differences between a tolerant and a sensitive genotype are presented. Altogether, we believe that this work will significantly contribute to broadening our understanding regarding how quinoa responds to long-term water stress highlighting genotype-related differences that will allow the selection of the best adapted genotypes for water-limiting environments. HighlightQuinoa physiological, phenological, and morphological distinct responses to long-term water stress depending on the genotype.

plant biology↗

bioRxiv2020

Soybean Yellow Stripe-like7 is a symbiosome membrane peptide transporter essential for nitrogen fixation

Legumes form a symbiosis with rhizobia that convert atmospheric nitrogen (N2) to ammonia which they provide to the plant in return for a carbon and nutrient supply. Nodules, developed as part of the symbiosis, harbor rhizobia which are enclosed in the plant-derived symbiosome membrane (SM), to form a symbiosome. In the mature nodule all exchanges between the symbionts occur across the SM. Here we characterize GmYSL7, a member of Yellow stripe-like family which is localized to the SM in soybean nodules. It is expressed specifically in nodule infected cells with expression peaking soon after nitrogenase becomes active. Although most members of the family transport metal complexed with phytosiderophores, GmYSL7 does not. It transports oligopeptides of between four and 12 amino acids. Silencing of GmYSL7 reduces nitrogenase activity and blocks development when symbiosomes contain a single bacteroid. RNAseq of nodules in which GmYSL7 is silenced suggests that the plant initiates a defense response against the rhizobia. There is some evidence that metal transport in the nodules is dysregulated, with upregulation of genes encoding ferritin and vacuolar iron transporter family and downregulation of a gene encoding nicotianamine synthase. However, it is not clear whether the changes are a result of the reduction of nitrogen fixation and the requirement to store excess iron or an indication of a role of GmYSL7 in regulation of metal transport in the nodules. Further work to identify the physiological substrate for GmYSL7 will allow clarification of this role. One sentence summaryGmYSL7 is a symbiosome membrane peptide transporter that is essential for symbiotic nitrogen fixation that when silenced blocks symbiosome development.

plant biology↗

bioRxiv2020

Medicago truncatula Yellow Stripe-Like7 encodes a peptide transporter required for symbiotic nitrogen fixation

Yellow Stripe-Like (YSL) proteins are a family of plant transporters typically involved in transition metal homeostasis. The substrate of three of the four YSL clades (clades I, II, and IV) are metal complexes with non-proteinogenic amino acid nicotianamine or its derivatives. No such transport capabilities have been shown for any member of the remaining clade (clade III), which is able to translocate short peptides across the membranes instead. The connection between clade III YSL members and metal homeostasis might have been masked by the functional redundancy characteristic of this family. This might have been circumvented in legumes through neofunctionalization of YSLs to ensure a steady supply of transition metals for symbiotic nitrogen fixation in root nodules. To test this possibility, Medicago truncatula clade III transporter MtYSL7 has been studied both when the plant was fertilized with ammonium nitrate or when nitrogen had to be provided by endosymbiotic rhizobia within the root nodules. MtYSL7 is a plasma membrane protein expressed in the vasculature and in the nodule cortex. This protein is able to transport short peptides into the cytosol, although none with known metal homeostasis roles. Reducing MtYSL7 expression levels resulted in diminished nitrogen fixation rates. In addition, nodules of mutant lines lacking YSL7 accumulated more copper and iron, the later the likely result of increased expression in roots of iron uptake and delivery genes. The available data is indicative of a role of MtYSL7, and likely other clade III YSLs, in transition metal homeostasis. ONE SENTENCE SUMMARYMedicago truncatula YSL7 is a peptide transporter required for symbiotic nitrogen fixation in legume nodules, likely controlling transition metal allocation to these organs.

plant biology↗

bioRxiv2019

Medicago truncatula Yellow Stripe1-Like3 gene is involved in symbiotic nitrogen fixation

Symbiotic nitrogen fixation carried out in legume root nodules requires transition metals. These nutrients are delivered by the host plant to the endosymbiotic nitrogen-fixing bacteria living with the nodule cells, a process in which vascular transport is essential. As occurs in root-to-shoot transport, members of the Yellow Stripe-Like (YSL) family of metal transporters should also be required for root-to-nodule metal delivery. The genome of the model legume Medicago truncatula encodes for eight YSL proteins, four of them with a high degree of similarity to Arabidopsis thaliana YSLs involved in long-distance metal trafficking. Among them, MtYSL3 is a plasma membrane protein expressed by vascular cells in roots and nodules, and by cortical nodule cells. Reducing expression levels of this gene had no major effect on plant physiology when assimilable nitrogen was provided in the nutrient solution. However, nodule functioning was severely impaired, with a significant reduction of nitrogen fixation capabilities. Further, iron and zinc accumulation and distribution changed. Iron was retained in the apical region of the nodule, while zinc became strongly accumulated in the nodule veins in the ysl3 mutant. These data suggest a role of MtYSL3 in vascular delivery of iron and zinc to symbiotic nitrogen fixation. HighlightMedicago truncatula YSL3 transporter is required for optimal nitrogen fixation in root nodules, mediating iron and zinc distribution in these organs.

plant biology↗