Innovative in vitro protocol for the screening of acetolactate synthase (ALS) herbicide resistance in Indian mustard (Brassica juncea L)

Abstract

Indian mustard plants show high sensitivity towards pre and post emergence herbicides, thus limiting the effective use of 
herbicides in the mustard crop. The acetolactate synthase (ALS) class herbicides are widely used in many cropping 
systems worldwide because of the availability of wide range of herbicides (sulfonylurea, metsulfuron, imidazolinone, 
triazolopyrimidine, pyrimidinyl (thio) benzoate, sulfonyl-aminocarbonyl-triazolinone). Consequently, it is crucial to 
address the development of ALS class herbicide resistance in Indian mustard. The important mechanisms for developing 
herbicide resistance in crops are hybridization, mutation, transgenics and genome editing. Crucial to these approaches is 
testing and selection for herbicide tolerance or resistance. However, conducting field screenings for herbicide resistance 
poses challenges due to its resource-intensive and time-consuming nature, compounded by the difculty of off-season 
screenings, which restrict the progression of herbicide resistance development programs. Consequently, we have 
devised an in vitro screening protocol specifically for the ALS class herbicide (metsulfuron), facilitating efcient and 
timely identication of herbicide resistance traits in Indian mustard.