Biology subjects

Diaz-Gonzalez, S.

Publications and source records attributed to Diaz-Gonzalez, S..

5 recordsLinked to original sources

bioRxiv2026

Reduced benzoxazinoid defences favour maize beneficial colonisation by Colletotrichum tofieldiae

O_LISpecialised defence metabolites mediate plant-microbe interactions, but their regulation during beneficial associations in cereals remains poorly understood. Here we investigate how maize (Zea mays) chemical defences are modulated during interaction with the beneficial fungal endophyte Colletotrichum tofieldiae (strain Ct0861) to promote host growth. C_LIO_LITo elucidate the molecular basis of this interaction, we combined transcriptomics, metabolite analyses and functional assays. To assess benzoxazinoids (BXs) roles at the plant-fungus interface, we compared Ct0861 colonisation and growth-promotion in wild-type maize and the BX-deficient bx1::DS mutant, using the pathogen Colletotrichum graminicola (CgM1.001) as reference. C_LIO_LITranscriptomic analyses revealed coordinated regulation of specialised defence pathways during the initial stages of Ct0861 colonisation, featuring systemic induction of terpenoid phytoalexin biosynthesis alongside localised suppression of roots BXs. Metabolomic analyses showed reduced apoplastic MBOA in Ct0861-colonised roots. Toxicity assays evidenced that Ct0861, unlike CgM1.001, is highly sensitive to MBOA. Accordingly, Ct0861 accumulation and growth-promoting effects were significantly enhanced in the bx1::DS mutant without causing disease symptoms. C_LIO_LIOur findings indicate that BXs restrict Ct0861 maize colonisation, where BX deficiency increases fungal biomass and enhances growth promotion. Understanding how crops fine tune specialised metabolism to balance microbial restriction with beneficial accommodation provides valuable insights for sustainable agriculture. C_LI

plant biology↗

bioRxiv2025

Plant Growth Promoting fungal endophyte Colletotrichum tofieldiae Ct0861 reduces mycotoxigenic Aspergillus fungi in maize grains

1.BackgroundMaize (Zea mays L.) is a globally critical crop that faces numerous challenges, including contamination by mycotoxigenic fungi such as Aspergillus spp., which threaten food safety and marketability. This study evaluates the potential of the fungal endophyte Colletotrichum tofieldiae strain Ct0861 as a bioinoculant to enhance maize productivity and investigates its impact on the maize-associated bacterial and fungal microbiomes. ResultsField trials showed that Ct0861 treatment enhances biomass and yield compared to controls, irrespective of the application method assayed (seed or spray application). Comprehensive microbiome profiling across soil, rhizosphere, roots, leaves, and grains revealed that Ct0861 inoculation induced subtle, compartment-specific effects on microbial diversity and composition, with similar effects for the two application methods used. Fungal alpha-diversity in grains was significantly reduced, while beta-diversity analyses showed localized shifts, particularly in soil and grain-associated microbial communities. Despite these changes, the core microbiome assemblages remained stable, indicating minimal alteration to the broader microbiome structure. Remarkably, Ct0861 significantly reduced the prevalence of Aspergillus spp. in maize grains, as confirmed by controlled infection assays. This reduction resulted in lower aflatoxin levels, demonstrating the biocontrol potential of Ct0861. ConclusionThese findings underscore Ct0861s dual benefits in enhancing crop yield and safety reducing fungal mycotoxin contamination. Further studies are necessary to elucidate the underlying mechanisms and expand its application across diverse agroecosystems.

microbiology↗

bioRxiv2025

Nematicidal and insecticidal activity of ethyl acetate extracts from culture filtrates of Arabidopsis thaliana fungal endophytes

Endophytic fungi produce a diverse range of bioactive secondary metabolites with potential applications in biopesticide development. This study investigates the nematicidal and antifeedant properties of ethyl acetate extracts from endophytic fungi isolated from wild Arabidopsis thaliana populations in Spain. The extracts were tested against the plant-parasitic nematode Meloidogyne javanica, and two common insect pests, Myzus persicae and Spodoptera littoralis. Nine of the 13 extracts demonstrated significant nematicidal and/or antifeedant activity, indicating their potential as biopesticides. The active extracts were derived from six genera: Alternaria (3 isolates), Dydimella (1), Dothiora (1), Pleiochaeta (1), Penicillium (1), and Fusarium (2). Five extracts exhibited nematicidal activity above 90%, with three reducing the total number of M. javanica second-stage juveniles hatched from egg masses by 22-37%. Four extracts showed strong settling inhibition (>70%) against M. persicae, and three exhibited feeding inhibition against S. littoralis. Chemical analysis by GC-MS and LC-MS revealed a wide array of unique secondary metabolites in the active extracts, reflecting substantial chemical diversity, regardless of the fungal origin. This study highlights the potential of fungal endophytes from A. thaliana as sources of novel biopesticides, paving the way for future research focused on harnessing these fungi for biopesticide development.

microbiology↗

bioRxiv2024

Maize associated bacterial and fungal microbiomes show contrasting conformation patterns that are resilient to water availability

Plant-associated microorganisms can help crops to alleviate water stress and increase the resilience of agricultural ecosystems to climate change. However, we still lack knowledge on the dynamics of bacterial and fungal microbial kingdoms within the soil and plant microbiomes and the response of these communities to different conditions such us, for example, water restrictions. This information is essential for the development of microbiome-based solutions to improve crop resilience to stressors associated to climate change. In this work, we explored: i) the conformation of the bacterial and fungal assemblages of different soil and plant compartments (bulk soil, rhizosphere, roots, leaves and grains) along the crop cycle of maize in an open field trial; and ii) the effect of water restriction on the maize microbiome comparing optimal irrigation with a 30% reduction of water supply. Our results show that microbial communities are highly structured along soil and plant compartments, with contrasting patterns for bacteria and fungi that were intensified towards the end of the plant cycle. Root showed the most differentiated bacterial assemblage while fungi conformed a very distinct community in the leaf, suggesting a relevant contribution of aerial fungal propagules to the microbiome of this plant organ. Despite the reductions in plant growth and yield, the microbiome of limited-watered plants did not show severe alterations. Still, significant impacts were observed within compartments, being fungi more responsive to limited watering than bacteria. Network analysis suggest that bacteria and fungi may play different roles in the shifts observed under water stress.

microbiology↗

bioRxiv2019

SIPA1L2 controls trafficking and signaling of TrkB-containing amphisomes at presynaptic terminals

Amphisomes are transient organelles that derive from fusion of autophagosomes with late endosomes. They rapidly transform into degradative autolysosomes, whereas non-degradative roles of the autophagic pathway have been barely described. Here we show that in neurons BDNF/TrkB receptor bearing Rab7 / Light chain 3 (LC3) - positive amphisomes signal at presynaptic boutons during retrograde trafficking to the soma. Local signaling and inward transport essentially require the Rap GTPase-activating (RapGAP) protein SIPA1L2, which directly binds to TrkB and Snapin to connect TrkB-containing amphisomes to dynein. Association with LC3 regulates the RapGAP activity of SIPA1L2 and thereby retrograde trafficking. Following induction of presynaptic plasticity amphisomes dissociate from dynein at boutons, and this enables local signaling and promotes transmitter release. Accordingly, sipa1l2 knockout mice show impaired BDNF-dependent presynaptic plasticity. Collectively, the data suggest that TrkB-signaling endosomes are in fact amphisomes that during retrograde transport have local signaling capacity in the context of presynaptic plasticity.

neuroscience↗