Numerous descriptions of organic molecules present in the Murchison meteorite have improved our understanding of the early interstellar chemistry that operated at or just before the birth of our solar system. However, all molecular analyses were so far targeted toward selected classes of compounds with a particular emphasis on biologically active components in the context of prebiotic chemistry. Here we demonstrate that a nontargeted ultrahigh-resolution molecular analysis of the solvent-accessible organic fraction of Murchison extracted under mild conditions allows one to extend its indigenous chemical diversity to tens of thousands of different molecular compositions and likely millions of diverse structures. This molecular complexity, which provides hints on heteroatoms chronological assembly, suggests that the extraterrestrial chemodiversity is high compared to terrestrial relevant biologicaland biogeochemical-driven chemical space.Fourier transform ion cyclotron resonance mass spectrometry | interstellar chemistry | nuclear magnetic resonance spectroscopy | organic chondrite | soluble organic matter M urchison chondrite is one of the most studied meteorites and became a reference for extraterrestrial organic chemistry (1). The diversity of organic compounds recorded in Murchison and in other carbon-rich carbonaceous chondrites (1-5) has clearly improved our understanding of the early interstellar chemistry that operated at or just before the birth of our solar system. More than 70% of the Murchison carbon content has been classified as (macromolecular) insoluble organic matter (IOM) of high aromaticity, whereas the soluble fraction contains extensive suites of organic molecules with more than 500 structures identified so far (6). These structures basically resemble known biomolecules, but are considered to result from abiotic synthesis because of peculiar occurrence patterns, racemic mixtures, and stable isotope contents and distributions. Most of the 100+ kg fragments of Murchison were collected shortly after it fell in Australia on September 28, 1969, so that neither of these fresh samples suffered from intensive terrestrial weathering (7).As a whole, Murchison is one of the least-altered chondrites (8), recently reclassified by Rubin et al. (9) as CM2.5, where the aqueous alteration index (2.5 petrologic subtype), based on petrographic and mineralogical properties of the meteorite, indicates that the primary lithology of Murchison had experienced a relatively low and uniform degree of aqueous alteration.Nevertheless, all previous molecular analyses were targeted toward selected classes of compounds with a particular emphasis on amino acids in the context of prebiotic chemistry as potential source of life on earth (10), or on compounds obtained in chemical degradation studies (11) releasing both genuine extractable molecules and reaction products (11-15) often difficult to discern unambiguously.Alternative nontargeted investigations of complex organic systems are now feasible using advanced analytical met...

Bacterial intraspecies and interspecies communication in the rhizosphere is mediated by diffusible signal molecules. Many Gram-negative bacteria use N-acyl-homoserine lactones (AHLs) as autoinducers in the quorum sensing response. While bacterial signalling is well described, the fate of AHLs in contact with plants is much less known. Thus, adsorption, uptake and translocation of N-hexanoyl- (C6-HSL), N-octanoyl- (C8-HSL) and N-decanoyl-homoserine lactone (C10-HSL) were studied in axenic systems with barley (Hordeum vulgare L.) and the legume yam bean (Pachyrhizus erosus (L.) Urban) as model plants using ultra-performance liquid chromatography (UPLC), Fourier transform ion cyclotron resonance mass spectrometry (FTICR-MS) and tritium-labelled AHLs. Decreases in AHL concentration due to abiotic adsorption or degradation were tolerable under the experimental conditions. The presence of plants enhanced AHL decline in media depending on the compounds' lipophilicity, whereby the legume caused stronger AHL decrease than barley. All tested AHLs were traceable in root extracts of both plants. While all AHLs except C10-HSL were detectable in barley shoots, only C6-HSL was found in shoots of yam bean. Furthermore, tritium-labelled AHLs were used to determine short-term uptake kinetics. Chiral separation by GC-MS revealed that both plants discriminated D-AHL stereoisomers to different extents. These results indicate substantial differences in uptake and degradation of different AHLs in the plants tested.

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