Figure 8.

Papilla-accumulation of YFP-HR3 is BFA sensitive while its targeting to the EHM is not. A, Surface-applied FM4-64 (20 μM) in 0.002% Silwet L-77 stained the PM and the papilla in 20 min (image on the left) but did not stain the EHM labeled by YFP-HR3 in 45 min (image on the right). B, When vacuum-infiltrated into leaf tissue (see “Materials and Methods”), FM4-64 could stain the EHM (arrow) labeled by RPW8.2-YFP as well as the haustorial membrane lobes. Notably, the haustorial neck is often more strongly stained (arrowhead). C, BFA inhibits focal accumulation of YFP-HR3 and callose to the papilla. Quantification of relative fluorescence intensity for YFP-HR3 and Sirofluor-stained callose at the papilla in confocal images. Data represent means ± se (n = 6) from one of two independent experiments. Student’s t test was used to compare the differences between treatments (* indicates P < 0.01, ** indicates P < 0.001). D, Representative images showing localization of YFP-HR3 to the PM, the papilla, and the EHM at 45 hpi in epidermal cells infiltrated with 1% DMSO buffer (upper panel) or 300 μM BFA (lower panel) at approximately 6 hpi from the base of the leaf. The EHM was labeled by RPW8.2-RFP and the callose was stained with Sirofluor. Note that both YFP-HR3 and callose were diminished in the papilla due to BFA treatment, but YFP-HR3 and RPW8.2-RFP at the EHM were unaffected. Bar, 10 μm in A to E. H, Haustorium; p, papilla.