Overexpression of ClWRKY48 from Cunninghamia lanceolata improves Arabidopsis phosphate uptake

Abstract

Our findings suggested that ClWRKY48 promoted the expression level of Arabidopsis phosphate transporter genes, enhanced phosphate uptake, and delayed the transition from the vegetative stage to the reproductive phase in Arabidopsis. Phosphorus (P) is an essential mineral for plants that influences their growth and development. ClWRKY48, one of the most highly expressed genes in the leaf, was identified by RT-PCR from Chinese fir [Cunninghamia lanceolata (Lamb.) Hook] (C. lanceolata). Furthermore, when treating C. lanceolata with increasing phosphate (Pi) concentration, the expression level of ClWRKY48 rose in leaves, the trends followed the increasing phosphate concentration treatment. ClWRKY48 is a transcription factor in C. lanceolata, according to the results of a yeast one hybridization experiment. Based on subcellular localization studies, ClWRKY48 is a nuclear-localized protein. Under Pi deficiency conditions, the phosphorus concentration of ClWRKY48 overexpressing Arabidopsis increased by 43.2-51.1% compared to the wild-type. Moreover, under Pi limiting conditions, the phosphate transporter genes AtPHT1;1 (Arabidopsis Phosphate transporter 1;1), AtPHT1;4, and AtPHO1 (Arabidopsis PHOSPHATE 1) were expressed 2.1-2.5, 2.2-2.7, and 6.7-7.3-fold greater than the wild-type in ClWRKY48 transgenic Arabidopsis, respectively. Under Pi-sufficient conditions, the phosphorus concentration and phosphate transporter genes of ClWRKY48 overexpression in Arabidopsis are not significantly different from the wild type. These findings indicated that ClWRKY48 increased phosphate absorption in transgenic Arabidopsis. Furthermore, compared to the wild type, the ClWRKY48 transgenic Arabidopsis not only had a delayed flowering time characteristic but also had lower expression of flowering-related genes AtFT (FLOWERING LOCUS T), AtFUL (FRUITFUL), and AtTSF (TWIN SISTER OF FT). Our findings show that ClWRKY48 enhances phosphate absorption and slows the transition from the vegetative to the reproductive stage in ClWRKY48 transgenic Arabidopsis.

Keywords: ClWRKY48; Flowering time; Phosphat transporter; Phosphate uptake; Transcription factor.