Identification and expression profile of dhurrin biosynthesis pathway genes in sorghum vegetative tissues

Sorghum is considered a fifth major cereal, widely used as a multipurpose crop worldwide. The use of sorghum as a major forage crop is limited due to cyanogenic glycoside dhurrin in the vegetative shoot tissues. This cyanogenic glycoside is harmful to livestock when fed as fodder. The present study selected three sorghum genotypes for estimating hydrogen cyanide potential (HCNp) in vegetative tissues under well-watered (WW) conditions. The HCNp concentration varied from genotype to genotype and ranged from 364 to 512 ppm. The HCNp estimation was observed more in ICSR 14001 with 511 ppm, followed by ICSV 93046 (443 ppm) and CSH 24 MF (364 ppm). A significant difference was noticed between the genotypes. Sequence information of dhurrin biosynthesis pathway genes was retrieved and characterized using different bioinformatic tools. The gene expression analysis of dhurrin biosynthesis pathway genes showed different expression patterns, with the highest in ICSV 93046 and less in ICSR 14001 and CSH 24 MF. Genes CYP79A1, CYP71E1 and UGT85B1 showed a 2.5- to 4 fold increase in ICSV 93046 and no significant expression in ICSR 14001 and CSH 24 MF. The genotype CSH 24 MF observed a 1.5-fold increase in CYP79A1 gene expression, and the other genes observed no significant increase. This study assisted in identifying the contrasting genotypes inducing HCNp and the key genes of the dhurrin pathway producing hydrogen cyanide (HCN) under WW conditions, which can be used as potential candidates for gene editing, providing safe feed for the livestock.