Meyerozyma guilliermondii promoted the deposition of GSH type lignin by activating the biosynthesis and polymerization of monolignols at the wounds of potato tubers

•M. guilliermondii increased enzyme activities of phenylpropane metabolism.•M. guilliermondii stimulated the three monolignol biosynthesis.•M. guilliermondii improved the activities of peroxidase and laccase, and the H2O2 content.•M. guilliermondii promoted the deposition of lignin which was identified as GSH type.•The G′2 and G6 units only exist in the treated wounds with M. guilliermondii. Lignin is a crucial component in the wound tissue of tubers. The biocontrol yeast Meyerozyma guilliermondii increased the activities of phenylalanine ammonia lyase, cinnamate-4-hydroxylase, 4-coenzyme coenzyme A ligase, and cinnamyl alcohol dehydrogenase, and elevated the levels of coniferyl, sinapyl, and p-coumaryl alcohol. The yeast also enhanced the activities of peroxidase and laccase, as well as the content of hydrogen peroxide. The lignin promoted by the yeast was identified as guaiacyl-syringyl-p-hydroxyphenyl type using Fourier transform infrared spectroscopy and two-dimensional heteronuclear single quantum coherence nuclear magnetic resonance. Furthermore, a larger signal area for G2, G5, G′6, S2, 6, and S′2, 6 units was observed in the treated tubers, and the G′2 and G6 units were only detected in the treated tuber. Taken together, M. guilliermondii could promote deposition of guaiacyl-syringyl-p-hydroxyphenyl type lignin by activating the biosynthesis and polymerization of monolignols at the wounds of potato tubers.