“…Otherwise, AVG and rhizobitoxine belong to the enol ether family and are a subclass of naturally occurring α-vinylic amino acids (Berkowitz et al, 2006; Boibessot et al, 2016) that are secreted by symbiotic rhizobacteria and pathogenic bacteria (Pruess et al, 1974; Owens et al, 1968; Mitchell et al, 1986; Yasuta et al, 2001). If these two natural compounds at low concentrations (< 5 μM) are known as inhibitors of two enzymes of methionine pathway involved in ethylene biosynthesis: cystathionine β-lyase and ACC synthase (Clausen et al, 1997; Yasuta et al, 1999; Rahman et al, 2000; Berkowitz et al, 2006), the role of their wide inhibitory spectrum on aminotransferases of N metabolism has been neglected in establishing symbiosis and increasing the nodule number (Peters and Crist-Estes, 1989; Xia et al, 2017).…”