Project description:This study evaluated the transcriptomic profiles of Arabidopsis thaliana (Col-0) plants grown along four SynCom treatments that induced differential primary root growth. Treatments Dropout Variovorax and DropoutVariovoraxBurkholderia induced primary root growth inhibition (RGI), while treatments Full and DropoutBurkholderia mantained a stereotypical long primary root.
Project description:Chemical signaling in the plant microbiome can have drastic effects on microbial community structure, and on host growth and development. Previously, we demonstrated that the auxin metabolic signal interference performed by the bacterial genus Variovorax via a novel auxin degradation locus was essential for maintaining stereotypic root development in an ecologically-relevant bacterial synthetic community. Here, we dissect the Variovorax auxin degradation locus to define the genes necessary and sufficient for indole-3-acetic acid (IAA) degradation and signal interference. We determine the crystal structures and binding properties of the operon’s MarR-family repressor with IAA and other auxins. We identify auxin-degradation operons across the bacterial tree of life and define two distinct types based on gene content and metabolic products: iac-like and iad-like. We solve the structures of MarRs from representatives of each auxin degradation operon type, establishing that each have distinct IAA binding pockets. Comparison of representative IAA degrading strains from diverse bacterial genera show that while all degrade IAA, only strains containing iad-like auxin degrading operons interfere with auxin signaling in a complex synthetic community context. This suggests that iad-like operon containing strains, including Variovorax species, play a key ecological role in modulating auxins in the plant microbiome.
Project description:We identified orthologs of the roX lncRNAs across diverse Drosophilid species, and then mapped the genomic binding sites of roX1 and roX2 in four Drosophila species (D. melanogaster, D. willistoni, D. virilis, and D. busckii) using ChIRP-seq (chromatin isolation by RNA Purification and sequencing), thus revealing the interplay of the evolution of roX1 and roX2 and their genomic binding sites.
Project description:Groupers (Epinephelidae) are ecologically, commercially, and culturally important predatory fishes throughout their global distribution range in tropical, subtropical and occasionally temperate regions. They are key species for modern and ancient fisheries in the Mediterranean which have been heavily overfished in the past century leading to smaller catch sizes, lower CPUE, and decreased biomass. There are four species of grouper native to the Mediterranean within the Epinephelus genus.The abundance and distribution of grouper species prior to the 20th century in the Mediterranean remains poorly known. Using peptide mass fingerprinting, also known as Zooarchaeology by Mass Spectrometry (ZooMS), we investigated if ZooMS is a viable method for identifying intra-genus grouper bones to species level. Due to the lack of publicly available genomic sequences and for validation of ZooMS markers, we reconstructed collagen type I amino acid sequences using LC-MS/MS for four Epinephelus spp. Adequate variation between collagen sequences enabled the production of the best supported phylogenetic tree for Mediterranean Epinephelus spp. to date. We identified 23 previously undescribed ZooMS biomarkers capable of distinguishing groupers to the species level. Our novel biomarkers were applied to a case study of 23 grouper/comber fish bones from the Middle to Late Holocene archaeological site of Kinet Höyük, located along the coast of Iskenderun Bay, Turkey. ZooMS markers enabled species level identification of 19 bones with 18 identified as Epinephelus aeneus and 1 identified as Epinephelus marginatus. Combining ZooMS identifications with catch size reconstructions has revealed that E. aeneus is capable of growing ca. 30 cm larger than previously reported. This abundance and dominance of E. aeneus locally at Kinet Höyük is consistent with E. aeneus being the most prevalent grouper species in Iskenderun Bay today, testifying to several millennia of this species local population persistence despite fishing pressure, habitat degradation, and climatic changes.