A proposed working model for MYB40 in the Arabidopsis response to As stress.
During As(V) stress, the expression of MYB40 is induced, and MYB40 then directly represses PHT1;1 expression to reduce As(V) uptake into plant cells. It also directly upregulates PCS1 expression to enhance the contents of PCs, which form complexes with As(III). MYB40 indirectly upregulates the expression of ABCC1 and ABCC2, which encode two major vacuolar PC transporters that carry As(III)-PC2 from the cytoplasm into the vacuole. Created with BioRender.com.