The small mustard plant ( Arabidopsis thaliana ) produces specialized metabolites capable of selectively altering the microbial communities of the soil surrounding its roots to suit its own purposes. While the findings may be useful in engineering beneficial root microbiota for sustainable agriculture, they may also, in part, explain why plants have evolved such vast metabolic diversification. Plants can produce an enormous variety of specialized metabolites, which has allowed them to adapt to nearly boundless ecological niches. An important environmental factor in their ability to thrive in a place is the microbiotic neighbors residing in the soil surrounding their roots. While it is estimated that a significant part of a plant's photosynthetic energy is used to make root-derived molecules thought to be important in promoting the formation of distinctive root microbiota from surrounding soil, the underlying mechanisms concerning the establishment of these communities remains elusive. Triterpenes, a large family of specialized plant metabolites with important functions in defense and signaling, have been shown to possess antifungal and antibacterial functions, which suggests a possible role for them in cultivating specific root microbiota. However, a substantial number of known root-expressed biosynthetic genes in plant genomes are uncharacterized and it's unknown whether and which metabolites are used in forging favorable root microbiota. Ancheng Huang and colleagues used metabolomic analysis and whole-genome sequencing to reveal a previously unknown triterpene biosynthetic network in the roots of A. thaliana. According to the results, the biosynthetic pathways of the network can synthesize a wide variety of triterpene compounds, including three - arabidin, thalianin and TFAE - that were shown to impact Arabidopsis root microbiota. According to Huang et al., In vitro bioassays showed growth-promoting and antibiotic activities towards different microbiome taxa, thus supporting this biosynthetic network's role in shaping A. thaliana-specific root microbiota.
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Science