Genome-wide characterization and expression analysis of WRKY transcription factors reveals biotic stress response potential mechanisms in Panax notoginseng

Abstract

WRKY transcription factors (TFs), among the largest families of transcriptional regulators, are essential players in defense responses in plants. Panax notoginseng, a traditional and precious herbal medicine in China, is widely cultivated due to its excellent medicinal and edible value. However, P. notoginseng is frequently affected by various diseases (like Black blot disease, Root rot disease and Viral diseases). Therefore, the present study aimed to identify and characterize PnWRKYs in the P. notoginseng genome, reveal their structural attributes, regulatory elements, and potential functions in defense responses. 68 PnWRKY TFs that have conserved domains and different physicochemical characteristics were identified in the genome. They can be divided into four groups according to phylogenetic relationships and conserved domain structures. Furthermore, Group II WRKY TFs can be classified into five subgroups (IIa, IIb, IIc, IId, and IIe) according to their zinc finger-like motif. The PnWRKY family expands mainly via segmental duplication. Additionally, the promoter regions of PnWRKYs contain many hormone-responsive and stress-responsive elements. Expression patterns under different hormones (salicylic acid, methyl jasmonate, and melatonin) and disease (root rot disease, black blot disease, and virus disease) treatment analysis highlighted their wide involvement in plant hormone-induced disease defense responses. These findings affirmed the potential functions of PnWRKY TFs in disease-mediated defense responses and provided valuable insights for future agricultural applications.