Saponin synthesis in Medicago truncatula plants: CYP450 ‐mediated formation of sapogenins in the different plant organs

CRISPR/Cas9-Mediated Targeted Mutagenesis of CYP93E2 Modulates the Triterpene Saponin Biosynthesis in Medicago truncatula

“…The major requirement for the successful engineering of specific saponins is the knowledge of the genes/enzymes involved in their biosynthesis. Over recent years, the economic relevance of these valuable natural compounds led to a substantial understanding of the biosynthetic routes of triterpene saponins, in particular in M. truncatula , a rich source of different saponins and a model plant species for legumes (Pateraki et al, 2015 ; Carelli et al, 2020 ). Several members of P450 families have been characterized to be involved in saponin biosynthesis of M. truncatula (Carelli et al, 2011 ; Fukushima et al, 2011 , 2013 ; Biazzi et al, 2015 ; Ribeiro et al, 2020 ) but the in planta function of a limited number of these P450s was determined.…”

“…Saponins are a large group of triterpene or steroid glycosides common to many plant species (Haralampidisis et al, 2002 ) exhibiting a wide spectrum of biological and pharmacological activities (Sparg et al, 2004 ; Tava and Avato, 2006 ; Augustin et al, 2011 ; Moses et al, 2014a ). These properties have, in the last decades, stimulated research on triterpene saponin biosynthetic pathways using Medicago truncatula (barrel medic) as model plant species (Carelli et al, 2020 ). In the Medicago genus, saponins are a complex mixture of olean-type glycosides with medicagenic acid, zanhic acid, hederagenin, bayogenin and soyasapogenols A and B as aglycones (Tava and Avato, 2006 ).…”

“…: soyasapogenols are characterized by a hydroxyl group at the C-24 position and are defined non-hemolytic sapogenins while hemolytic sapogenins have a hydroxyl or carboxyl group at C-23 and a carboxyl group at C-28 (Tava et al, 2011 ) ( Figure 1 ). The hemolytic and non-hemolytic sapogenins are synthesized through independent biosynthetic pathways, and have different chemical structures, biological activity and distribution in plant organs (Tava et al, 2011 ; Carelli et al, 2020 ). In particular, hemolytic sapogenins such as bayogenin, hederagenin, medicagenic acid, zanhic acid and their glycosides, which represent the most abundant saponins in the Medicago genus, showed significant biological and pharmacological properties, including fungistatic, insecticidal, antimicrobial, antifeeding, apoptotic, nematocidal, anthelmintic, cytotoxic, hypocholesterolemic, antiatherosclerotic, neuroprotective and anticarcinogenic activities (Avato et al, 2006 , 2017 ; Tava and Avato, 2006 ; Argentieri et al, 2008 ; Balestrazzi et al, 2011 ; Rafińska et al, 2017 ; Maestrini et al, 2019 , 2020 ; D'Addabbo et al, 2020 ).…”

“…In particular, hemolytic sapogenins such as bayogenin, hederagenin, medicagenic acid, zanhic acid and their glycosides, which represent the most abundant saponins in the Medicago genus, showed significant biological and pharmacological properties, including fungistatic, insecticidal, antimicrobial, antifeeding, apoptotic, nematocidal, anthelmintic, cytotoxic, hypocholesterolemic, antiatherosclerotic, neuroprotective and anticarcinogenic activities (Avato et al, 2006 , 2017 ; Tava and Avato, 2006 ; Argentieri et al, 2008 ; Balestrazzi et al, 2011 ; Rafińska et al, 2017 ; Maestrini et al, 2019 , 2020 ; D'Addabbo et al, 2020 ). On the other hand, the soyasapogenol saponins are lacking of hemolytic characteristics and for this reason they have a low biological and pharmacological activity (Tava and Avato, 2006 ; Argentieri et al, 2008 ; Rafińska et al, 2017 ; Carelli et al, 2020 ). Due to their properties, hemolytic saponins from Medicago spp.…”

Genome-Wide Identification and Analyses of Drought/Salt-Responsive Cytochrome P450 Genes in Medicago truncatula

“…In vitro drought stress via PEG treatment increased saponin content and antioxidant activity in Agave salmiana plants [30]. In the genus Medicago, saponins are a complex mixture of oleanane-type triterpenic glycosides were both constitutively synthesized and induced in response to biotic/abiotic stresses [31]. In the present study, the expression level of CYP72A59v1 was increased under drought stress and extremely significant increased under PEG treated at 24 h,48 h and 72h, and the expression level of CYP72A66 was significantly increased from 24 h under NaCl treatment, suggesting that both CYP72A59v1 and CYP72A66 are involved in saponin biosynthesis in response to drought/salt stress in M. truncatula.…”