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Gema Puebla

@gemapuebla.bsky.social

Science is my passion. Finishing my PhD at Di Pietro's lab, investigating and loving Fusarium oxysporum

Gema Puebla @gemapuebla.bsky.social · 06/10/2026

Ultimately, we demonstrated that insertion of a spok contributes to mitotic stability of the DC10, while deletion of the spok from DC12 triggers its instability, highlighting the role of selfish elements in shaping fungal genomes. Thanks to all the authors for their contribution 😊

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Gema Puebla @gemapuebla.bsky.social · 06/10/2026

We hypothesized that the selfish element may have a role in the maintenance of the DC12. To experimentally test our idea, we designed two complementary approaches: 1) inserting the spok from DC12 of Fol4287 into the unstable DC10 of MRL8996 and 2) removing the spok from DC12 of Fol4287.

The spok element contributes to the mitotic stability of DCs.

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Gema Puebla @gemapuebla.bsky.social · 06/10/2026

So how does Fol4287 never lose its DC12? Genomic alignment shows that DC12 carries a giant 92.5 kb Starship transposon that harbours a Spore Killer (spok) gene. This region is completely absent in MRL8996 DC10.

DC12 of Fol4287 contains a Giant Starship Element absent in DC10 of MRL8996.

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Gema Puebla @gemapuebla.bsky.social · 06/10/2026

So if DC10 is so easily lost, why is it retained in the MRL8996 population? 🤔 Fitness assays demonstrate that DC10 confers a competitive advantage when growing MRL8996 on non-preferred carbon sources and, importantly, on plant tissue 🪴

Loss rate of DC10 of MRL8996 when growing on different carbon sources and competition experiments between MRL8996 wt vs MRL8996 -DC10

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Gema Puebla @gemapuebla.bsky.social · 06/10/2026

Experimental evolution followed by sequencing analysis revealed that the F. oxysporum isolate MRL8996 carries a dispensable chromosome (DC10) that is rapidly lost under non-selective conditions. However, its homolog in Fol4287 (DC12) is highly stable under the same conditions 😱

Different DC stability of two F. oxysporum strains

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Gema Puebla @gemapuebla.bsky.social · 06/10/2026

Starting my bluesky with this super exciting new! New preprint from Di Pietro's Lab www.biorxiv.org/content/10.6... How do fungal pathogens maintain dispensable chromosomes without losing them in clonal evolution? Here's a thread 🧵

biorxiv.org

Killer meiotic driver prevents chromosome loss and enhances fitness in a fungal pathogen

Fungal pathogens often carry dispensable chromosomes (DCs) that confer a selective advantage in adverse environments or during host infection but can be spontaneously lost under non-selective conditio...

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