## 2 Results
### Ab-FAR-1 Asp Can Affect AtADF3-Mediated Actin Filament Depolymerisation  
Real-time quantitative PCR results showed that there was no significant difference between the expression levels of the AtADF3 gene in _A. thaliana_ overexpressing Ab-FAR-1 Asp and WT _A. thaliana_, indicating that Ab-FAR-1 Asp did not affect the expression of AtADF3 (Figure 8a). The recombinant AtADF3 protein (rAtADF3) was obtained by prokaryotic expression, and it was found to depolymerise actin filaments in vitro by high-speed co-sedimentation assay and fluorescence microscopy (Figure S6 and Figure 8b,c--panel T1). Then, four mixture samples (CK, T1-T3) in which rAb-FAR-1 Asp, rAtADF3, BSA, and F-actin were mixed in different combinations were determined by high-speed co-sedimentation assay, and the supernatants and pellets were analysed by SDS-PAGE. In the F-actin alone (CK) sample, many actin filaments were present in the pellet, and a small number in the pellet. The concentration of the actin filaments in the pellet was determined by the ratio of the actin filaments in the pellet. The concentration of the actin filaments in the pellet was determined by the ratio of the actin filaments in the pellet. The concentration of the actin filaments in the pellet was determined by the ratio of the actin filaments in the pellet. The concentration of actin filaments in the pellet was determined by the ratio of the actin filaments in the pellet.  
supernatant. The actin filament content in the pellets of the rAtADF3 and F-actin mixture sample (T1) and the rAtADF3, BSA, and F-actin mixture sample (T2) was significantly lower (\(p<0.05\)) than that of the CK sample, and the contents in the supernatant were significantly higher (\(p<0.05\)) than that of the CK sample. The pellet and supernatant contents of the T2 sample were not significantly different from those of the T1 sample. These results indicate that rAtADF3 efficiently depolymerised F-actin in vitro and was not affected by BSA. However, the actin filament content in the pellet of the rAb-FAR-1 Asp, rAtADF3, and F-actin mixture sample (T3) was significantly lower (\(p<0.05\)) than that of the CK sample but significantly higher (\(p<0.05\)) than that of the T1 and T2 samples, and the content in the supernatant was also significantly lower than that of the T1 and T2 samples (Figure 8b). These results indicate that AtADF3 could still depolymerise F-actin, but the depolymerisation ability was inhibited when rAb-FAR-1 Asp was added, indicating that rAb-FAR-1 Asp could inhibit the actin depolymerisation ability of AtADF3. In addition, phalloidin staining results showed that the fluorescence intensity of the actin filaments was significantly lower (\(p<0.05\)) in the pellets of the T1, T2, and T3 samples than in those of the CK sample, while the fluorescence intensity of the actin filaments in the T3 sample was significantly higher (\(p<0.05\)) than that of T1 and T2. Some filamentous F-actin remained in the T3 sample (Figure 8c,d). Therefore, the interaction between Ab-FAR-1 secreted by RWTNs and AtADF3 from the host inhibited the actin filament depolymerisation function of AtADF3, which might further affect the turnover process of the actin cytoskeleton in host plant cells.