Biology subjects

Martinez-Lopez, M.

Publications and source records attributed to Martinez-Lopez, M..

3 recordsLinked to original sources

bioRxiv2026

CRISPR/Cas12a-mediated allele engineering of SmAPRR2 and SmGLK2 reveals complementary control of fruit peel and flesh chlorophyll pigmentation in eggplant

Eggplant (Solanum melongena L.) displays extensive fruit color diversity, in which chlorophyll-related pigmentation contributes to both external appearance and market value. Previous genetic studies identified SmAPRR2 and SmGLK2 as major candidate genes controlling uniform green pigmentation and green netting in fruit, respectively, but their individual and combined functional contributions had not been validated through targeted mutagenesis in a common genetic background. Here, we established a multiplex CRISPR/Cas12a system in eggplant accession MEL3, representing, to our knowledge, the first application of this nuclease for genome editing in eggplant. Transformation efficiency was 2.0%, but all 15 genotyped regenerants were edited, yielding four SmAPRR2 and six SmGLK2 alleles. Segregation and crossing enabled the recovery of six transgene-free lines carrying single or combined edited alleles. Disruption of SmGLK2 abolished the reticulated green netting pattern while preserving a uniformly green peel and the internal green ring. Conversely, disruption of SmAPRR2 reduced the background uniform peel pigmentation and eliminated the green ring while retaining green netting. Double mutants carrying disruptive alleles at both loci produced white fruits lacking internal green pigmentation, whereas putatively hypomorphic SmAPRR2 and SmGLK2 alleles generated intermediate phenotypes. Whole-genome resequencing identified only two predicted off-target sites under a canonical TTTV PAM search allowing up to four mismatches. Both were fully covered, and no edited-line-specific candidate variants were detected. These findings establish complementary and partially separable roles for SmAPRR2 and SmGLK2 in fruit peel and flesh chlorophyll pigmentation and demonstrate the potential of Cas12a for functional genomics, allele engineering, and precision breeding in eggplant.

plant biology↗

bioRxiv2025

Micro-Mel and Mini-Mel short life cycle dwarf lines with Solanum anguivi introgressions as the first model varieties for eggplant research and breeding

Eggplant (Solanum melongena) research has been hindered by the lack of suitable model plants. The development of Micro-Mel and Mini-Mel, two short-cycle dwarf model lines with introgressions from the wild relative S. anguivi, represents a breakthrough in eggplant research. Both lines were characterized with 30 phenotypic descriptors and compared to their parental lines and the Micro-Tom tomato. Micro-Mel has determinate growth, early flowering (41.0 days post-transplantation), and physiological fruit maturity at 103.7 days. Mini-Mel exhibits indeterminate growth, later flowering (57.2 days) and fruit maturity (114.7 days), with a more conventional architecture. Micro-Mel and Mini-Mel complete 3.5 and 3.0 full seed-to-seed cycles per year, respectively. Their compact size makes them ideal for space-limited environments, controlled growth chambers, speed breeding, ornamental horticulture, and urban horticulture. To validate their potential for gene editing, in vitro regeneration experiments were performed on a medium containing zeatin riboside. Regeneration was similar to parental S. melongena (1.2 shoots/explant), with Micro-Mel developing 1.0 and Mini-Mel 0.8. Whole-genome sequencing (23X coverage) identified 179,653 SNPs between the parental lines, revealing heterozygosity rates of 0.00098% for Micro-Mel and 0.00123% in Mini-Mel. Approximately 8.50% and 10.79% of their genomes were introgressed from S. anguivi, respectively. Analysis identified 18 shared introgressions from S. anguivi among Micro-Mel, Mini-Mel, and four backcross dwarf materials derived from the same original plant. Notably, three orthologues of genes associated with dwarfism in tomato (SlDREB1, SlER, and SlSERK1) were identified within these introgressions. Micro-Mel and Mini-Mel represent transformative tools for eggplant research, accelerating genetic, physiological, and breeding studies.

plant biology↗

bioRxiv2024

Macrophages drive the earliest anti-tumoral response to BCG therapy by directly killing bladder cancer through TNF signaling

The Bacillus Calmette-Guerin (BCG) vaccine is the cancer immunotherapy longest in use. Despite its effectiveness in bladder cancer (BC), its initial mechanisms of action remain largely unknown. Therefore, proper diagnostic assessments to identify patients who will not respond to treatment or develop resistance are lacking. Here, we set-out to unravel the earliest innate cellular mechanisms involved in BCG-induced clearance of tumors. We show that BCG induces a massive recruitment of macrophages to the tumor microenvironment and modulates their morphology and behavior towards a proinflammatory phenotype, while also promoting macrophage fusion-like events. We demonstrate that macrophages directly induce apoptosis and clearance of cancer cells through TNF-signaling and that they are indispensable for this antitumoral response since their depletion completely abrogates the BCG-anti tumor effect. Contrary to the general concept that macrophage antitumoral activities uniquely rely on stimulating an effective adaptive response, we demonstrate that macrophages alone can directly induce tumor killing and clearance; revealing an additional step to the BCG-induced tumor immunity model, that was not previously considered. In addition, we also provide proof-of-concept experiments demonstrating the potential of this unique in vivo preclinical model to test new innate immunomodulators.

cancer biology↗