Biology subjects

Martinez-Martinez, A.

Publications and source records attributed to Martinez-Martinez, A..

3 recordsLinked to original sources

bioRxiv2026

SlCIPK26 enhances tomato fertility by activating the K+ transporter SlHAK5 in reproductive tissues

In tomato plants, the potassium (K) transporter SlHAK5 is integral to root K uptake and overall plant fertility. Under K deficiency, SlHAK5 expression is induced in roots and the encoded transporter is activated via the Ca{superscript 2}-sensing CIPK/CBL complex SlCIPK23/SlCBL1-9. In Arabidopsis, multiple CIPK/CBL complexes can activate AtHAK5, providing alternative regulatory pathways that enhance K uptake. However, the architecture of CIPK/CBL signaling networks has diverged among plant species, necessitating species-specific identification of novel regulatory components. Accordingly, we screened additional tomato CIPK proteins for their capacity to modulate SlHAK5 activity in yeast. SlCIPK15 and SlCIPK26 emerged as potent activators of SlHAK5, acting in concert with SlCBL9. Functional characterization of slcipk15 and slcipk26 mutants revealed that neither contributed significantly to SlHAK5-mediated K uptake in roots. Conversely, both mutants exhibited impaired pollen tube elongation, correlating with reduced K content in pollen relative to wild type. Notably, slcipk26 mutants displayed more severe pollen defects, phenocopying the slhak5 mutant. Further analyses demonstrated that slcipk26 plants suffered compromised seed set and pistil function, paralleling the reproductive deficiencies observed in slhak5 mutants. These findings implicate SlCIPK26 as the principal regulator of SlHAK5 in reproductive tissues. Collectively, our data underscore the role of CIPK paralogs in orchestrating tissue-specific regulation of target proteins, thereby enabling fine-tuned modulation of K transport essential for both vegetative and reproductive development.

plant biology↗

bioRxiv2025

Single-Cell Dissection of Immunometabolic Rewiring in the Porcine Ileum during Salmonella Typhimurium Infection

Salmonella Typhimurium is a major zoonotic pathogen, with pigs acting as important subclinical carriers. To explore the specific intestinal immune response at the cellular level, we used Single-cell RNA sequencing (scRNA-seq), enabling detailed analysis of immune cell types and gene expression profiles during infection. In addition to enterocytes, our results revealed the presence of diverse immune populations, including monocytes/macrophages, dendritic cells, innate lymphoid cells (ILCs), thirteen T cell subtypes and five B cell populations were identified, revealing pronounced infection-driven alterations in cellular composition and transcriptional states. Among T cells, naive and follicular CD4+/CD8+ {beta} T cells and NK T cells were expanded, whereas effector CD8+ T cells and CD2- and SELLhi {gamma}{delta} T cells were decreased. B-cell populations shifted toward activated and cycling states, with decreased antibody-secreting, resting, and transitioning cells. Dendritic cells and monocyte/macrophage populations were expanded, and group 3 ILCs and enterocytes were markedly reduced. Pathway analyses revealed robust cell type-specific immunometabolic remodeling, including enhanced protein-folding and stress-adaptive pathways in T and B cells, heightened inflammatory, interferon, and cytokine signaling in myeloid populations, and coordinated metabolic and immune adjustments in epithelial cells, highlighting the complexity of host responses to Salmonella infection. This study provides the first scRNA-seq landscape of the porcine ileum during S. Typhimurium infection, offering insight into host immune cell dynamics and immunometabolic responses.

genomics↗

bioRxiv2025

Genome dynamics across the radiation of a mega-diverse genus

Understanding the drivers of species diversity and rapid radiations is a major goal in evolutionary biology. Begonia is one of the most species-rich angiosperm genera with 2,164 species currently identified. This genus exhibits considerable variation in chromosome number and a wide range of genome sizes, allowing us to associate genome dynamics with divergence and speciation at a range of temporal scales. We investigate all main radiations within the Begoniaceae family using five previously published Begonia genomes and seven new genome assemblies. We show that Begonia species show more complex, repetitive and dynamic genomes overall than their close relative, the monotypic Hillebrandia sandwicensis. We identify families of repetitive elements that have recently expanded in species from two different highly speciose Southeast Asian sections and two large Neotropical radiations. Detailed characterisation of genomes from species belonging to two parallel radiations, one in Southeast Asia (Begonia section Coelocentrum) and the other in the Neotropics (Begonia section Gireoudia), revealed recent expansion in LTR retrotransposons (LTR-RTs) and satellite DNA, in contrast to more species-poor closely related clades. We further investigate variation in repetitive elements within species, finding that accessions from a population of the widespread Begonia heracleifolia with unusually large genomes show a markedly higher satellite repeat and Ty3/Gypsy LTR-RT content associated with the expansion of a few abundant repeat lineages. We find that accessions derived from this population show lower seed viability in crosses with other conspecific populations, and thus identify a direct link between expansions of repetitive DNA and the process of genetic isolation. These results show how genome dynamics may promote speciation in one of the most diverse flowering plant genera.

genomics↗