Genome-wide identification and expression analysis of the WRKY gene family reveal essential roles in abiotic stress responses and polysaccharides and flavonoids biosynthesis in Platostoma palustre (Blume) A. J. Paton

Abstract

Background

Platostoma palustre (Blume) A. J. Paton is an economic crop with medicinal and edible properties. WRKY transcription factors are widely involved in the growth and development, response to adversity stress, and hormone transduction of plants. The identification of the WRKY gene family has been completed in many plants, however, it has not yet been identified and analyzed at the genome-wide level in P. palustre.

Results

In this study, we identified 133 PpWRKY gene family members (PpWRKYs) at the whole genome level of P. palustre, which were unevenly distributed on 15 chromosomes. Based on their protein structure and phylogenetic characteristics, the 133 PpWRKYs were divided into 3 subgroups. Segmental duplication events might play a crucial role in the expansion of the PpWRKY gene family. Through the transcriptome expression data analysis, the expression profiles of PpWRKY genes under Cd, red light, salt, and drought stresses were analyzed in this study, suggesting that WRKY transcription factors may play a crucial role in responding to different abiotic stresses in P. palustre. Notably, PpWRKY92 exhibited simultaneous responses to Cd, light intensity, salt, and drought stresses. Additionally, PpWRKY21, 75, 90, 52, 124, 39, 115, 122, 20, and 76 demonstrated a strong correlation with both monosaccharides and flavonoids. Taken together, PpWRKY20, 39, 75, 76,90, 92, 115, 122, and 124 were found to be associated with the abiotic stress response and polysaccharides and flavonoids biosynthesis in P. palustre, except the low-expressed PpWRKY21 and 52.

Conclusion

The present study laid the foundation for the abiotic stress response and metabolite regulation of this gene family in P. palustre.