Biology subjects

Makhon, A.

Publications and source records attributed to Makhon, A..

3 recordsLinked to original sources

bioRxiv2026

Conserved inhibitory mechanisms of root-associated bacteria towardsArabidopsis thaliana and Chlamydomonas reinhardtii

Soil bacteria colonize plants without causing visible disease, yet many suppress host growth. The prevalence and evolutionary reach of this cryptic inhibition are unknown, because phenotyping hundreds of isolates in plants is prohibitively slow. Here we use the unicellular algae Chlamydomonas reinhardtii as a scalable proxy for the green lineage. We screened 148 plant-associated bacteria on Chlamydomonas lawns. Seven of eight Chlamydomonas inhibitors also inhibited the vascular model plant Arabidopsis thaliana. In one of these dual inhibitors, Burkholderia sola MF6, transposon screening and proteomics implicated type VI secretion and tight-adherence pili, and over half the non-inhibitory mutants also failed against Arabidopsis. In the algae, infection triggers rapid deflagellation, then non-lytic regulated cell death. The algal zinc/iron transporter ZIP3 promotes inhibition, whereas the cathepsin X protease CEP12 restrains it, and ZIP3 is epistatic to CEP12. Cryptic inhibition is thus ancient and widespread, and a unicellular algae uncovers it at scale.

plant biology↗

bioRxiv2026

The ribosome-associated quality control factor Vms1 protects mitochondrial import and homeostasis during translation stress

Mitochondrial protein synthesis and import are tightly coordinated to maintain cellular proteostasis, yet how cytosolic translation stress affects mitochondrial homeostasis remains poorly understood. Here, we investigated the cellular consequences of general translation stress using low-dose translation inhibitors in Saccharomyces cerevisiae. Genome-wide phenotypic screening revealed that the deletion of tRNA-hydrolase VMS1 involved in mitochondria-associated ribosomal quality control (mitoRQC) causes a unique hypersensitivity to low-dose cycloheximide. Quantitative proteomics demonstrated that translation stress triggers specific depletion of mitochondrial proteins, reduced respiratory capacity, and impaired mitochondrial membrane potential. Most notably, cytosolic translation stress strongly inhibited mitochondrial protein import, an effect that was substantially exacerbated in vms1{Delta} cells. We further identify the mitochondrial AAA-ATPase Msp1 as a protective factor during translation stress. Msp1 expression increased in vms1{Delta} cells, and its overexpression restored growth under stress, linking co-translational quality control to mitochondrial protein import surveillance. Together, our findings reveal mitochondrial protein import as a major target of cytosolic translation stress and uncover functional cooperation between mitoRQC and Msp1 in safeguarding mitochondrial proteostasis and cell survival.

cell biology↗

bioRxiv2026

Expanding The Algal Hydrogen Toolbox: A Non-GMO Platform Reveals Multiple Physiological Routes To Sustained Hydrogen Production Across Microalgae

Sustainable hydrogen production from microalgae remains limited by intrinsic physiological constraints and the need to preserve biomass value for food and feed applications. Transgenic approaches to overcome these limitations were proven successful, yet result in genetically modified (GMO) strains that face major regulatory and deployment barriers. Here, we present a non-GMO experimental platform that enables systematic isolation of hydrogen-producing phenotypes through high-throughput UV mutagenesis pipline coupled with targeted physiological screening. Applying this approach across phylogenetically distinct algal species, including the industrial strain Chlorella vulgaris and the extremophile Chlorella ohadii, we achieve high discovery efficiency, recovering 0.4-0.6% validated hydrogen-producing mutants and achieving 6.7-25% validation rates among screen-positive candidates, indicating strong enrichment at the primary screening stage. We show that sustained hydrogen production represents a physiologically accessible state emerging across diverse genetic backgrounds. This state is consistently associated with reorganization of photosynthetic electron partitioning, yet arises through multiple distinct configurations that differentially balance hydrogen production, oxygen metabolism, and carbon fixation. This framework provides a scalable route to identify hydrogen-producing strains in industrially relevant algae without introducing foreign DNA and expands the accessible design space for photobiological hydrogen production.

plant biology↗