With an ever-increasing amount of (meta)genomic data being deposited in sequence databases, (meta)genome mining for natural product biosynthetic pathways occupies a critical role in the discovery of novel pharmaceutical drugs, crop protection agents and biomaterials. The genes that encode these pathways are often organised into biosynthetic gene clusters (BGCs). In 2015, we defined the Minimum Information about a Biosynthetic Gene cluster (MIBiG): a standardised data format that describes the minimally required information to uniquely characterise a BGC. We simultaneously constructed an accompanying online database of BGCs, which has since been widely used by the community as a reference dataset for BGCs and was expanded to 2021 entries in 2019 (MIBiG 2.0). Here, we describe MIBiG 3.0, a database update comprising large-scale validation and re-annotation of existing entries and 661 new entries. Particular attention was paid to the annotation of compound structures and biological activities, as well as protein domain selectivities. Together, these new features keep the database up-to-date, and will provide new opportunities for the scientific community to use its freely available data, e.g. for the training of new machine learning models to predict sequence-structure-function relationships for diverse natural products. MIBiG 3.0 is accessible online at https://mibig.secondarymetabolites.org/.

Microorganisms are found everywhere, and they are closely associated with plants. Because the establishment of any plant-microbe association involves chemical communication, understanding crosstalk processes is fundamental to defining the type of relationship. Although several metabolites from plants and microbes have been fully characterized, their roles in the chemical interplay between these partners are not well understood in most cases, and they require further investigation. In this review, we describe different plant-microbe associations from colonization to microbial establishment processes in plants along with future prospects, including agricultural benefits.

Secondary metabolites produced by endophytic microorganisms can provide benefits to host plants, such as stimulating growth and enhancing the plant's resistance toward biotic and abiotic factors. During its life, a host plant may be inhabited by many species of endophytes within a restrictive environment. This condition can stimulate secondary metabolite production that improves microbial competition and may consequently affect both the neighboring microorganisms and the host plant. The interactions between the endophytes that co-habit the same host plant have been studied. However, the effect of these interactions on the host plant has remained neglected. When using mixed microbial cultures, we found that the endophytic fungus Alternaria tenuissima significantly increased the production of some polyketides, including antifungal stemphyperylenol in response to the endophytic Nigrospora sphaerica. Biological activity assays revealed that stemphyperylenol can cause cytotoxic effects against N. sphaerica, although no phytotoxicity was observed in the host plant Smallanthus sonchifolius, even at concentrations much higher than those toxic to the fungus. The polyketides produced by A. tenuissima may be important for the ecological relationships between endophyte-endophyte and endophytes-host plants in the natural environment.