Bioinformatical analysis and prediction of Nicotiana benthamiana bHLH transcription factors in Phytophthora parasitica resistance

The basic helix-loop-helix (bHLH) family, one of the largest transcription factor groups in plants, regulates many critical developmental processes. However, their functions in plant defense have not been extensively studied in Nicotiana benthamiana, an important model plant species for phytopathology. Here, we identified N. benthamiana bHLH genes (NbbHLHs) using a whole-genome searching approach, and found that the NbbHLHs are highly enriched and some subfamilies are selectively expanded in N. benthamiana. The results showed that gene duplication may be responsible for bHLH family expansion in this plant. Furthermore, we analyzed their expression profiles upon infection with Phytophthora parasitica. Finally, 28 candidate NbbHLHs may play important roles in Phytophthora pathogen resistance using cis-element analysis and protein-interaction network prediction. Taken together, our results established a platform for future studies of the gene family and provide molecular insights into plant immune responses against P. parasitica.