Herbicide Resistance and Cross-Resistance: Changes at Three Distinct Sites in the Herbicide-Binding Protein

Science  12 Apr 1985:
Vol. 228, Issue 4696, pp. 204-207
DOI: 10.1126/science.228.4696.204


Plants and algae resistant to the commonly used s-triazine herbicides display a wide spectrum of cross-resistance to other herbicides that act in a similar manner. Analysis of uniparental mutants of the green alga Chlamydomonas reinhardi showed that three different amino acid residues in the 32-kilodalton thylakoid membrane protein can be independently altered to produce three different patterns of resistance to s-triazine and urea-type herbicides. These results clarify the molecular basis for herbicide resistance and cross-resistance. Two of the mutations do not alter normal electron transport and thus may have applications of agronomic interest.