2,4-dichlorophenoxy acetate (2,4-D) is a commonly used herbicide for the control of broad-leafed weeds in wheat, maize and rice. Its auxin-like action has been extensively exploited for induction of roots in plant tissue cultures. Over the past few years, however, 2,4-D has become focus of attention because of its potential to modify plant roots vis-à-vis bacterial infection. This role of 2,4-D has immense significance in understanding the mechanism of legume-Rhizobium symbiosis and extending this phenomenon to cereal crops. The need to make the plant roots harbour bacteria (particularly those capable of fixing atmospheric nitrogen) and the role of 2,4-D in facilitating the process has been reviewed. 
