Pecial concentrate on their biosynthesis in heterologous hosts.INDUSTRIAL APPLICATIONS OF ISOFLAVONOIDSIsoflavonoids are generally present in low amounts in seeds and roots with the Leguminosae/Fabaceae family which includes a number of frequently consumed plants like barley, broccoli, cauliflower, fava beans, lupine, kudzu, and soy (Prasad et al., 2010; Table 1). Traces of isoflavonoids are also present in red wine and in other plants like alfalfa, red clover and linseed (Pilsakova et al., 2010). Rather interestingly, isoflavonoids have also been identified from at the very least 59 non-leguminous plant families (i.e., Iridaceae, Rosaceae, and Liliaceae), because it is normally believed that isoflavonoids’ biosynthetic machinery is just not widely distributed in plant households except legumes (Lap , 2007). cRole in PlantsWith rising climate and environmental pressures, the potential utilization of isoflavonoids in planta to enhance plant resistance against herbivore insects and to improve the interactions on the plant with all the rhizobiome has resulted in increased interest and research (Dillon et al., 2017). Isoflavonoids produce a spectrum of positive aspects for the host plant (Figure 2). Isoflavonoids play a vital role in plant defense, as they possess a array of antimicrobial activities (usually analyzed in vitro) (Dixon, 1999). They are well-known as plant defensive chemicals and are active against vertebrates, molluscs, herbivorous insects, and microorganisms (Dakora and Phillips, 1996; Nwachukwu et al., 2013). One example is, the wellknown isoflavonoid pterocarpans, maackiain, and pisatin play a vital part as phytoalexins inside the interaction involving Nectria haematococca as well as the host plant Pisum sativum (garden pea) (Wasmann and VanEtten, 1996; Enkerli et al., 1998). Both of those pterocarpans are targets of fungal CYP26 Inhibitor site virulence factors and detoxification enzymes, which indicates their significance for the host plant. Lately, Dillon and colleagues have shown that UV-B-induced accumulation of genistein enhances resistance of field-grown soybean plants against Anticarsia gemmatalis BRD9 Inhibitor site neonates (Dillon et al., 2017). A 30 reduction in survival and 45 reduction in mass achieve of larvae was documented, along with the authors have concluded that UV-B-induced accumulation of isoflavonoids increases the resistance of plants against A. gemmatalis (Dillon et al., 2017). An overview of UV-B-based induction of isoflavonoids is described in section “Regulation of Isoflavonoid Biosynthesis in Plants.” Isoflavonoids are certainly not only active inside the cell but additionally play a beneficial part in the rhizosphere. The part of isoflavonoids inside the induction of nodulation genes and as allelopathic agents has also been documented (Dixon, 1999). Daidzein, secreted by soybean roots, acts as a signaling molecule for nodulation and alters the structure and functioning of rhizosphere communities (Okutani et al., 2020). Along with this, isoflavonoids play a role in theFrontiers in Bioengineering and Biotechnology | www.frontiersin.orgJuly 2021 | Volume 9 | ArticleSajid et al.Current Advances in Isoflavonoid BiosynthesisFIGURE 1 | Simple skeleton of isoflavonoids: isoflavonoids are structurally distinctive to flavonoids, with the B-ring migration from position two to three, which in turn results in the structural similarities to estrogen, e.g., 17-estradiol. Isoflavonoid diversity is regulated by easy functional additions which include hydroxyl, which in turn can generate further rings in to the backbone, e.g., pterocarpan and coum.