Identification and Expression Analysis of GARP Superfamily Genes in Response to Nitrogen and Phosphorus Stress in Spirodela Polyrhiza

Abstract

Background: GARP transcription factors perform the critical roles in plant development and response to environmental stimulate, especially in the phosphorus (P) and nitrogen (N) sensing and uptake. Spirodela polyrhiza (giant duckweed) is widely used for phytoremediation and biomass production for its efficient N and P removal capacity and rapid growth. However, there has not yet been a comprehensive analysis of the GRAP gene family in S. polyrhiza. Results: We conducted a comprehensive study of the GARP genes in S. polyrhiza. First, we investigated 35 SpGARP genes in S. polyrhiza, which have been classified into three groups on the basis of their gene structure, conserved motifs and phylogenetic relationship. Then, we identified the duplication events, performed the synteny analysis, calculated the Ka/Ks ratio in SpGARP genes. Next, the regulation and co-expression networks of SpGARPs were constructed using cis-acting element analysis and weighted correlation network analysis (WGCNA). Last, the expression pattern of SpGARP genes were performed used RNA-seq date and qRT-PCR, several members of group IId were involved in both N and P starvation response. Conclusions: The study provide insight into the evolution and functional annotation of GARP gene family in S. polyrhiza, and lays the foundation for the further functional verification of SpGARP genes.