Biology subjects

Escola, G.

Publications and source records attributed to Escola, G..

3 recordsLinked to original sources

bioRxiv2026

Integrative genomic and regulatory network analysis reveals adaptive mechanisms to salt-alkalinity stress in Brassica fruticulosa

Salinity poses a widespread and increasing threat to plant fitness, ultimately constraining agricultural productivity worldwide. An inherent roadblock to understanding the precise physiological impacts of high-salinity soils is the frequent co-occurrence of multiple stressors. In calcareous soils, salinity typically coincides with alkalinity. To address this realistic combinatorial stress scenario, we deconstructed the enhanced performance of the coastally distributed, salt-tolerant Brassica fruticulosa under salt-alkaline conditions using comparative physiological, transcriptomic, and genomic analyses across major brassica crops. First, to gain a high-resolution genomic view, we generated phased, chromosome-level genome assemblies of B. fruticulosa and performed cross-species comparisons of transcriptome-derived Gene Regulatory Networks (GRNs) among important related crop models with contrasting salt tolerances. These results revealed that B. fruticulosa mounts predominantly root-centered transcriptional responses to cope with high salinity, whereas salt-sensitive species rely largely on shoot-level mechanisms to mitigate salt toxicity. Consistently, regulatory modules within GRNs diverged substantially between organs and among species, reflecting distinct adaptive programmes of varying efficacy. Functional categorisation of transcription factors with high centrality in B. fruticulosa shoot GRNs highlighted processes related to iron (Fe) homeostasis, suggesting that effective maintenance of Fe allocation to aerial tissues supports biomass retention under combined salt and alkalinity stress. Collectively, these findings establish B. fruticulosa as a valuable new model for dissecting adaptation to salinity in natural environments and provide mechanistic insight into the regulatory architecture underlying salt-alkaline tolerance.

plant biology↗

bioRxiv2024

Local cryptic diversity in salinity adaptation mechanisms in a wild outcrossing Brassica

It is generally assumed that populations of the same species should evolve shared mechanisms of adaptation to common stressors due to evolutionary constraint. Here, we describe a novel system of within-species local adaptation to coastal habitats, Brassica fruticulosa, and detail surprising mechanistic variability in adaptive responses to extreme salinity. These radically different adaptive responses in neighbouring populations are evidenced by transcriptomes, diverse physiological outputs, and completely distinct genomic selective landscapes. In response to high salinity Northern Catalonian populations restrict root-to-shoot Na+ transport, favouring K+ uptake. Contrastingly, Central Catalonian populations accumulate Na+ in leaves and compensate for the osmotic imbalance with compatible solutes such as proline and elevated Ca2+. Despite contrasting responses, both metapopulations were salinity tolerant relative to all inland accessions. To characterise the genomic basis of these two divergent adaptive strategies in an otherwise non-saline-tolerant endemic, we generate a long-read-based genome and population sequencing of 18 populations (9 inland, 9 coastal) across the B. fruticulosa species range. Results of genomic and transcriptomic approaches confirm the physiological observations of completely distinct underlying mechanisms of adaptation to extreme salinity and reveal potential genetic targets of these two recently evolved salinity adaptations. We therefore provide a new model of within-species salinity adaptation and reveal cryptic variation in neighbouring plant populations in the mechanisms of adaptation to an important natural stressor highly relevant to agriculture. SignificanceIts usually expected that closely related populations of a given species should adapt to the same environmental stressor in the same way due to genetic or physiological constraints. However, this is not commonly tested due to practical constraints. Here we show that, even at the level of neighbouring populations, contrasting adaptive mechanisms control adaptive responses to extreme coastal salinity in a new plant model, Brassica fruticulosa, a close wild relative of many crops of worldwide importance. This indicates multiple options for engineering an agriculturally crucial adaptation: soil salinization. These results will be of great interest to not only those studying fundamental mechanisms of adaptation, but also resilience improvement in Brassica species.

evolutionary biology↗

bioRxiv2023

At the core of salinity: convergent and divergent transcriptome response pathways to neutral and alkaline salinity in natural populations of Arabidopsis thaliana

More than 70% of lands cultivated area is affected by alkaline salinity stress. As 98% of plants are glycophytes - unable to successfully reproduce under salinity - our previous research focused on comparative studies of Arabidopsis thaliana demes with differential performance under neutral and alkaline salinity (neuSAL and alkSAL) due to local adaptation processes. Here, an integrated analysis on leaf tissue was performed, including physiological indicators, nutritional status, endogenous phytohormonal concentration and transcriptome profiling, to further understand differences in molecular mechanisms underlying neuSAL and alkSAL responses. The results support that alkSAL is more detrimental to plant performance than neuSAL and indicate higher sensitivity to alkSAL in demes locally adapted to coastal siliceous soils. A decreased internal Fe use efficiency in coastal demes under alkSAL is proposed to be the driver of their enhanced sensitivity, and sequence variation at {beta}-CA1 and -CA1 locus is hypothesized to contribute to the imbalance of Fe homeostasis. Dissection on the down-regulated transcripts shared by neuSAL and alkSAL confirmed enhanced inhibition of central features on primary and secondary metabolism in coastal individuals under alkSAL. The cell wall and vacuolar {beta}-galactosidase BGAL4 was revealed as a candidate for conferring tolerance to neuSAL by favoring stress-regulated cell wall rearrangement, but not to alkSAL, probably due to pH-restricted enzymatic activity. In addition, differential modulation of endogenous phytohormonal cues was reported among salinity types and demes, by which higher alteration of the auxinic, ethylene and jasmonic acid signaling pathways was exerted by alkSAL but sustained ABA biosynthesis was detected only in coastal plants under neuSAL. Weighted correlation network analysis (WGCNA) confirmed the involvement of the identified candidate genes in co-expression modules significantly correlating with favorable responses to neuSAL and alkSAL. Overall, the present study provides useful insights into key targets for breeding improvement in alkaline saline soils.

molecular biology↗