Functional Analysis Of Transcription Factor GmPTF1and GmPHR1Responsed To Low Phosphorus In Soybean

Phosphorus plays a pivotal role in plant growth and development, and the deficiencyof available phosphorus in the soil will cause serious reduction both in quality and quantityof crops. By the cloning and using low-P tolerant genes to breed high phosphorusefficiency varieties is an efficient strategy for sloving deficiency of available phosphorus insoil. In the present study, two transcription factor genes, GmPTF1and GmPHR1wereanalysed in activation locus, subcellular localization, sequence and expression differences,as well as functions of GmPTF1and GmPHR1in transgenic Arabidopsis. The main resultswere as follows:1. By the method of bioinformatics analysis, two copies of GmPTF1were found insoybean genome, located on chromosome3and chromosome19, respectively. Thefull-length of GmPTF1was8275bp, including six introns and seven exons. The twocopies of GmPHR1in soybean genome, located on chromosome3and chromosome19in soybean genome, respectively. The full-length of GmPHR1was2751bp, includingfive introns and six exons.2. Analysis of GmPTF1and GmPHR1cDNA sequence revealed that there were nodifference between low-Pi tolerant (ZH15) and sensitive (NMH) variety, and a G-Asingle nucleotide polymorphism was present in low-Pi tolerant (JD11, ZH15) andsensitive (NMH) variety, and leaded to an amino acid alteration of GmPHR1in NMH.3. Real-time qPCR analysis showed that GmPTF1transcripts were more abundant in allorgans sampled from the tolerant variety ZH15than those from the sensitive varietyNMH, especially in the roots under low-Pi stress from0d to56d. In the tolerantvariety JD11, GmPHR1was quickly induced and reached to a higher peak at0.5h afterlow-Pi stress, then the expression level decreased slowly at6h and reached to thehighest peak at12-24h after stress. While in the sensitive variety NMH, GmPHR1wasslowly induced and reached to a peak at6h after stress, then decreased quickly at9hafter stress. More importantly, the GmPHR1relative expression levels of JD11weremuch higher than those in NMH from0.5h to48h after stress all the time. 4. Yeast one-hybrid showed that the N-terminal and C-terminal peptide of GmPTF1, andthe C-terminal peptide of GmPHR1can act as the transcriptional activators. Subcellularlocalization and fluorescence microscopy observation in cells of transgenicArabidopsis root showed that the translated protein GmPTF1and GmPHR1werelocated in the nucleic.5. The comparison of transgenic Arabidopsis and wild type under phosphate stressshowed that the root/shoot ratio of plants overexpressing GmPTF1was higher than thatof wild and RNAi plants, and the maximum root length of RNAi plants was shorterthan that of other plants. The dry weights of of root, overground part, total plant,root/shoot ratio and the maximum root length of GmPHR1overexpression plants werehigher than those of wild type and RNAi plants. The dry weight of root and total plantof RNAi plants were lighter than that of wild type. This suggested that GmPTF1andGmPHR1were useful genes in conferring plant tolerrance to phosphorus starvation.