## Results and Discussion
### Nematode Responsive Phytohormones and Transcription Factors
Members of several families of TFs (WRKY, bZIP, bHLH, NAC, MYB, and AP2/ERF) are well-known in regulating plant immune response [52]. In this study, we detected differential regulation of genes encoding for ERF, WRKY, MYB, bZIP, and DOF family of TFs among others (Figure 7A). Classification and identification of the differentially expressed TFs was attained from the Plant Transcription Factor Database ([[http://planttfdb.cbi.pku.edu.cn/](http://planttfdb.cbi.pku.edu.cn/)]([http://planttfdb.cbi.pku.edu.cn/](http://planttfdb.cbi.pku.edu.cn/)) v.4.0) [53]. Most of the differentially expressed TFs in the current data set were down-regulated (298/532) after nematode infestation (Table S6). The importance of TFs in mediating potato disease resistance to _Pectobacterium brasiliense 1692_ and _Plytophthora infestans_ infestation has been reported previously [17; 18]. This is an indication that TFs are key regulators of potato immune response to various biotic stresses. In this study, most of the genes (70.37%) encoding for AP2/ERF TF family were down-regulated at both 3 and/or 7 dpi. In addition, 15 genes were suppressed to a greater extent at 7 than 3 dpi (Figure 7B and Table S6). This could be ascribed to the secretion of nematode effectors and subsequent suppression of defense response associated with the activation of AP2/ERF TFs. The ERF subfamily of AP2/ERF TFs are important transcriptional regulators of genes responsive to biotic stress, particularly genes related to the JA and ET hormone signaling pathway [52]. Interestingly, we found three genes encoding for ERF6 up-regulated following _M. javancia_ infestation (Figure 7B and Table S6). This could imply that ERF6 TFs have a negative role in mediating potato susceptibility to _M. javancia_. Furthermore, seven genes coding for DREB were down-regulated in this study (Figure 7B and Table S6). It is generally accepted that pathogen-directed modulation of WRKY genes in plants is an important aspect that enhances success rates of pathogen infestation. Cyst nematode's successful infestation process in _A. thaliana_ roots was attributed to the nematode's control over the expression of WRKY genes [54]. In agreement with this notion, we found 23 genes down-regulated WRKY-encoding genes, including _WRKY40, WRKY23, and WRKY29_ both infection stages (Figure 7C and Table S6). The MYB TFs have been characterized as an important regulator of both biotic and abiotic stresses [55]. Among the 34 down-regulated MYB TFs in this study, we found genes encoding for _MYB108_ (3 genes), _MYB105_, and _MYB 14_ at 3 and 7 dpi (Figure 7D and Table S6). We also identified genes encoding for DNA-binding with one finger (DOF) TFs (14 out 17 genes up-regulated (Figure 7E and Table S6), transcriptional regulators acting on the formation and function of vascular tissues [56]. This further highlights the importance of vascular-related genes in establishment and formation of NFSs, therefore successful _M. javanica_ colonization. Overall, the large number of differentially expressed TFs in this study reflects the complexity associated with plant defense regulation which orchestrates plant immunity leading to physiological alteration of the host to favor _M. javanica_ infestation.