FIGURE 5.

Systematic examination of the inhibitory effect on ABI1 by PYLs in response to pyrabactin revealed a common determinant of pyrabactin selectivity. A, inhibition of ABI1 by 12 PYLs in response to pyrabactin. The concentration of all PYLs was set at 4 μm, and three concentrations of pyrabactin (1, 10, and 100 μm) were tested for each PYL. The details of the experiments are described under “Experimental Procedures.” B, sequence alignment reveals that the single-residue alteration between valine and isoleucine underlies the distinct pyrabactin selectivity by PYLs. PYL5 and PYL6, which contain valine at the corresponding position, are sensitive to pyrabactin due to a distinct mechanism which will be discussed in a separate manuscript.