Fig 1.
Phylogenetic tree of coding nucleotide sequences of the phosphate transporter family 1 (PHT1) in Brassica napus, B. oleracea, B. rapa and Arabidopsis thaliana.
The phylogenetic tree was constructed by MEGA 5.1 with neighbor-joining method and 1000 replicates. The analysis involved 109 nucleotide sequences including 49 from B. napus (pink red rectangle), 28 from B. rapa (light blue triangle), 23 from B. oleracea (light yellow star) and nine from Arabidopsis (light green circle).
Fig 2.
Schematic representations for the chromosomal distribution and interchromosomal relationships of rapeseed PHT1 genes.
Gray lines indicate all syntenic blocks in the Brassica napus genome, and the blue lines indicate syntenic PHT1 gene pairs. The chromosome number is indicated at the bottom of each chromosome. R, random.
Fig 3.
Synteny analysis of PHT1 genes in Brassica napus, B. rapa, B. oleracea and Arabidopsis thaliana chromosomes.
Gray lines in the background indicate the collinear blocks within B. napus and other plant genomes, while the red lines highlight the syntenic PHT1 gene pairs. Genes located on B. napus A genome are syntenic with genes of B. rapa and A. thaliana, while genes located on B. napus C genome are syntenic with genes of B. oleracea and A. thaliana.
Fig 4.
Expression profiles of the PHT1 family genes in the leaves and roots of Brassica napus under various nutrient stress conditions.
Seedlings of 14 days old were exposed to various nutrient deficiency environments for six days. The fully expanded leaf and roots were sampled separately for RNA extraction. L, leaf. R, roots. CK, full strength Hoagland’s solution. Pd, phosphorus deficiency. Nd, nitrogen deficiency. Kd, potassium deficiency. Sd, sulfur deficiency. Fed, iron deficiency. The color scale is shown on the right side. Gray box indicates data undetected. Heat map of gene expression profiles was generated using pheatmap package in R after data normalization.
Fig 5.
Expression profiles of the PHT1 family genes in the leaves and roots of Brassica napus under salt and drought stresses.
For salt stress analysis, 14-d-old seedlings were treated with Hoagland’s solution containing 150mM NaCl for six days. For drought stress analysis, seedlings of 14 days old were treated with Hoagland’s solution containing 20% (W/V) PEG for three days. The full expanded leaf and roots were sampled separately for RNA extraction at harvest. L, leaf. R, roots. CK, full strength Hoagland’s solution. NaCl, salt stress. The color scale is shown on the right side. Gray box indicates data undetected. Heat map of gene expression profiles was generated using pheatmap package in R after data normalization.
Fig 6.
Expression profiles of the PHT1 family genes in leaves and roots of Brassica napus under auxin (IAA) and cytokinin (CTK) treatments.
Seedlings of 14 days old were treated with Hoagland’s solution containing 100 μM IAA and 100 μM CTK for six days, respectively. The fully expanded leaf and roots were sampled separately for RNA extraction at harvest. L, leaf. R, roots. CK, full strength Hoagland’s solution. The color scale is shown on the right side. Gray box indicates data undetected. Heat map of gene expression profiles was generated using pheatmap package in R after data normalization.
Fig 7.
Coexpression networks of 15 PHT1 family genes in Brassica napus.
Cycle nodes represent genes, and the size of the nodes represents the power of the interrelation among the nodes by degree value. The width of the lines between two nodes represent interactions between genes. The PHT1 family genes located in the center of the network, while the 10 most coexpressed genes were displayed in each network.
Fig 8.
Cis-elements in the 2.0-kb promoter regions of the PHT1 family genes in Brassica napus.
(A) Enrichment of the cis-elements in the promoter sequences of BnaPTs. The size of the sequence represents the frequency of the cis-elements in the promoter regions. (B) Distribution of nine cis-elements in the promoters of 23 PHT1 family members. These cis-elements are associated with P homeostasis (P1BS and W-BOX), salt stress response (GT-1 and DRE), drought stress response (MYCR and MBS), and auxin response (TATC-BOX, TGA and CATATGGMSAVR).