AGO1 and HSP90 buffer different genetic variants in Arabidopsis thaliana

Argonaute 1 (AGO1), the principal protein component of microRNA-mediated regulation, plays a key role in plant growth and development. AGO1 physically interacts with the chaperone HSP90, which buffers cryptic genetic variation in plants and animals. We sought to determine whether genetic perturbatio...

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Bibliographic Details
Published inbioRxiv
Main Authors Lemus, Tzitziki, Mason, Grace A, Bubb, Kerry L, Alexandre, Cris M, Queitsch, Christine, Cuperus, Josh T
Format Paper
LanguageEnglish
Published Cold Spring Harbor Cold Spring Harbor Laboratory Press 30.09.2022
Subjects
Alleles
Arabidopsis thaliana
Epistasis
Flowering
Gene loci
Gene mapping
Genetic diversity
Hsp90 protein
miRNA
Mutants
Phenotypes
Rosette
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Summary:Argonaute 1 (AGO1), the principal protein component of microRNA-mediated regulation, plays a key role in plant growth and development. AGO1 physically interacts with the chaperone HSP90, which buffers cryptic genetic variation in plants and animals. We sought to determine whether genetic perturbation of AGO1 in Arabidopsis thaliana would also reveal cryptic genetic variation, and if so, whether AGO1-dependent loci overlap with those dependent on HSP90. To address these questions, we introgressed a hypomorphic mutant allele of AGO1 into a set of mapping lines derived from the commonly used Arabidopsis strains Col-0 and Ler. Although we identified several cases in which AGO1 buffered genetic variation, none of the AGO1-dependent loci overlapped with those buffered by HSP90 for the traits assayed. We focused on one buffered locus where AGO1 perturbation uncoupled the traits days to flowering and rosette leaf number, which are otherwise closely correlated. Using a bulk segregant approach, we identified a non-functional Ler hua2 mutant allele as the causal AGO1-buffered polymorphism. Introduction of a non-functional hua2 allele into a Col-0 ago1 mutant background recapitulated the Ler-dependent ago1 phenotype, implying that coupling of these traits involves different molecular players in these closely related strains. Taken together, our findings demonstrate that even though AGO1 and HSP90 buffer genetic variation in the same traits, these robustness regulators interact epistatically with different genetic loci, suggesting that higher-order epistasis is uncommon. Competing Interest Statement The authors have declared no competing interest. Footnotes * Minor changes to the manuscript, primarily in the introduction and discussion
DOI:10.1101/2022.06.27.497824