Amino acid substrate specificities and tissue expression profiles of the nine CYP79A encoding genes in Sorghum bicolor.

Koleva DT, Liu M, Dusak B, Ghosh S, Krogh CT, Hellebek IR, Cortsen MT, Motawie MS, Jørgensen FS, McKinley BA, Mullet JE, Sørensen M, Møller BL

Published: 10 December 2024 in Physiologia plantarum
Keywords: No keywords in Pubmed
Pubmed ID: 39749417
DOI: 10.1111/ppl.70029

Cytochrome P450s of the CYP79 family catalyze two N-hydroxylation reactions, converting a selected number of amino acids into the corresponding oximes. The sorghum genome (Sorghum bicolor) harbours nine CYP79A encoding genes, and here sequence comparisons of the CYP79As along with their substrate recognition sites (SRSs) are provided. The substrate specificity of previously uncharacterized CYP79As was investigated by transient expression in Nicotiana benthamiana and subsequent transformation of the oximes formed into the corresponding stable oxime glucosides catalyzed by endogenous UDPG-glucosyltransferases (UGTs). CYP79A61 uses phenylalanine as a substrate, whereas CYP79A91, CYP79A93, and CYP79A95 use valine and isoleucine as substrates, with CYP79A93 showing the ability also to use phenylalanine. CYP79A94 uses isoleucine as a substrate. Analysis of 249 sorghum transcriptomes from two different sorghum cultivars showed the expression levels and tissue-specific expression of the CYP79As. CYP79A1 is the committed gene in dhurrin formation and was the highest expressed gene in most tissues/organs. CYP79A61 was primarily expressed in fully developed leaf blades and leaf sheaths. CYP79A91 and CYP79A92 were expressed mainly in roots >200 cm below ground, while CYP79A93 and CYP79A94 were most highly expressed in the leaf collar and leaf sheath, respectively. The possible signalling effects of the oximes and their metabolites produced in different sorghum tissues are discussed.

Carlsberg Foundation Research Infrastructure grant - LCMS Ion-Trap based research towards climate resilient crop plants CF19-0301
Carlsberg Foundation Semper Ardens grant - Crops for the future - Tackling the challenges of changing climates CF20-0352
DOE Great Lakes Bioenergy Research Center - DOE BER Office of Science grant/Award DE-SC00118409
Novo Nordisk Foundation NNF21OC0071074
VILLUM Foundation grant to VILLUM Center for Plant Plasticity VKR 023054/00007523