The basic helix-loop-helix (bHLH) transcription factor bHLH130 negatively regulates tomato resistance to Phytophthora infestans.

Tomato is a widely cultivated horticultural crop with high economic value worldwide. However, its yield is highly threatened by the infection by Phytophthora infestans. The basic helix-loop-helix (bHLH) transcription factors form a large family in plants and play key roles in responding to both biotic and abiotic stresses. In our previous study, we identified the transcription factor bHLH130 as being closely associated with P. infestans, but its specific function remains unclear. In this study, transient overexpression and virus induced gene silencing (VIGS) experiments revealed that bHLH130 acts as a negative regulator of tomato resistance to P. infestans. Furthermore, stable RNA interference (RNAi)-mediated silencing of bHLH130 resulted in enhanced tomato resistance, as evidenced by changes in reactive oxygen species (ROS) accumulation and upregulation of pathogenesis-related (PR) genes. Transcriptome sequencing of WT and RNAi plants following P. infestans infection indicated that bHLH130 may regulate tomato resistance through hormone signaling transduction and phenylpropanoid biosynthesis. In conclusion, our results implicate bHLH130 as a pivotal component of tomato defense responses. These findings could provide novel insights into the genetic mechanisms underlying tomato immunity and offer potential targets for the horticultural improvement of tomato traits.