Biology subjects

del Pozo, J. C.

Publications and source records attributed to del Pozo, J. C..

3 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↗

bioRxiv2025

DNA Methylation Dynamics Reveal Unique Plant Responses and Transcriptional Reprogramming to Combined Heat and Phosphate Deficiency Stress

Plants adapt to environmental challenges through epigenetic mechanisms that modulate gene expression without altering DNA sequence. Among these, DNA methylation is central to balancing genome stability and transcriptional flexibility. We analyzed methylation dynamics in Arabidopsis thaliana under heat, phosphate deficiency, and their combination--conditions that frequently co-occur in nature--using whole-genome bisulfite sequencing, small RNA-seq and RNA-seq of shoots and roots in a setup closely mimicking field conditions. Stress-specific patterns emerged: heat and combined stress led to CHH hypomethylation in both shoot and root, while phosphate deficiency triggered hypermethylation in shoots but hypomethylation in roots. Importantly, the epigenetic response to combined stress was not a mere additive effect of individual stresses but displayed a distinct methylation signature. While both RdDM and CMT2 pathways contributed to heat-induced changes, CMT2 predominated under phosphate deficiency and combined stress, underscoring mechanistic specificity. Methylation changes concentrated in transposable elements (TEs) and intergenic regions, yet TE methylation shifts showed limited correlation with TE or adjacent gene expression, suggesting methylation does not act as a direct transcriptional switch. Instead, stress-induced methylation may influence chromatin accessibility at regulatory regions, particularly transcription factor binding sites; GATA motifs appeared as especially relevant in our analyses. A striking signature emerged in the nuclear mitochondrial DNA (NUMT) region, where hypomethylation under heat and combined stress correlated with upregulation of oxidative phosphorylation genes, critical for thermotolerance. Our findings highlight DNA methylation as an intricate regulatory layer integrating environmental signals into plant adaptive responses, offering a foundation for strategies to harness epigenetic plasticity for crop resilience under climate change.

plant biology↗

bioRxiv2019

Stem Cell Activity And Regeneration In Roots Require Non-Cell Autonomous Regulation From The Ground Tissue

Stem cells are central to plant development. During root postembryonic development stem cells generating tissues are patterned in layers around a stem cell organizer or quiescent center (QC). How stem cell lineages are initially patterned is unclear. Here, we describe a role for BLUEJAY (BLJ), JACKDAW (JKD) and SCARECROW (SCR) transcription factors in patterning of cell lineages during growth and in patterning reestablishment during regeneration through regulation of number of QC cells and their regenerative capacities. In blj jkd scr mutants, QC cells are progressively lost which results in loss of tissue layers. Upon laser ablation blj jkd scr is impaired in QC division and specification resulting in severe impairment in pattern regeneration. Beyond direct regulation of QC activity by these transcription factors, reduced levels of SHORT-ROOT (SHR) and of PIN auxin transporters were observed in the vasculature of blj jkd scr, leading to strong reduction in the auxin response in the QC. We narrowed down non-cell-autonomous regulation of vascularly expressed genes in blj jkd scr to C-REPEAT BINDING FACTOR 3 (CBF3). cbf3 mutant shows reduced levels of SHR in the vasculature, and in addition QC disorganization and downregulation of the QC regulator WUSCHEL-RELATED HOMEODOMAIN 5 (WOX5). CBF3 gene is primarily expressed in the ground tissue downstream of BLJ, JKD and SCR, while CBF3 protein may move. Targeted-expression of CBF3 to the ground tissue of blj jkd scr recovers radial patterning and regeneration. We propose that BLJ, JKD and SCR regulate QC-mediated patterning, and that part of this regulation involves CBF3.

developmental biology↗