Sequencing of the acetolactate synthase gene in the milk thistle, Silybum marianum (L.)Gaertn

Milk Thistle (Silybummarianum (L.) Gaertn) is a common weed species for wheat, barley and corn fields in, Iran. Acetolactate synthase (ALS) is a chloroplastic enzyme that encoded by a nuclear gene. ALS catalyzes the first step in the biosynthesis of branched-chain amino acids. Sulfonylureas herbicidesinhibit the growth of plants by blocking ALS enzyme activity Resistance to this family of herbicides has been observed in some of the weed species due to a mutation in the ALS gene. Therefore, ALS gene sequencingsurveyof herbicide-resistant biotypes is necessary for detecting unknown mutations. In this study, for the first time sequencing of the ALS gene in Milk Thistle was done. To this end, were designed a total of five degenerate primer pairs based on the sequence of this gene in other species of the Asteraceae family, so that neighbor produced amplicons, overlapped together about 200-300 bp. Then, they were amplified by polymerase chain reaction (genomic DNA used as a template). Sequencing of PCR products was done based Sanger method. Then, the sequenced parts were assembled using their overlapping sections. A total of 1921 bp of the gene was sequenced in Milk Thistle, which covered 88% of the ALS gene sequence in Arabidopsis (2009 bp) with a similarity of 74%.

کلیدواژه ها:

Mutation ، Herbicide resistance ، Sulfonylureas herbicides ، Silybum marianum L.