Figures (8)  Tables (3)

    • Figure 1. 

      Phylogenetic tree of ABCB family genes and distribution of conserved protein motifs.

    • Figure 2. 

      Location of cis-elements in the ABCB genes' promoter sequences.

    • Figure 3. 

      Collinearity analysis of ABCB genes in tomato species from chromosome 1 to 12.

    • Figure 4. 

      Collinear correlation of the ABCB gene family between Solanum lycopersicum L. and (a) Arabidopsis thaliana, (b) Oryza sativa, and (c) Solanum melongena.

    • Figure 5. 

      Phylogenetic tree constructed using MEGA 6.0 by NJ the method based on a total of 58 ABCB proteins comprising 29 S. lycopersicum and 29 Arabidopsis ABCB proteins. The phylogenetic tree reveals seven main clusters (1–7).

    • Figure 6. 

      Heatmap of SlABCB genes determined by microarray analysis and RNA-Seq data. The heatmap was generated using TBtools software using the RNA-Seq data.

    • Figure 7. 

      Expression of ABCB genes in tomato under cadmium stress, determined by qRT-PCR. The data in the figure were obtained from three biological replicates (n = 3), presented as the means + standard error (SE). Significance differences are denoted by different lowercase letters (p < 0.05), according to Duncan's multiple range test.

    • Figure 8. 

      Functional verification of SlABCB genes in yeast. SlABCB8, SlABCB15, SlABCB22, and SlABCB26 were transformed into Cd-sensitive strains of Saccharomyces cerevisiae Δyap1 to test their function of mediating tolerance to excess Cd. P/Y, wild-type Y252 transformed with the empty pYES2 vector; P/Δ, the cadmium-sensitive yeast mutant Δyap1 transformed with the empty pYES2 vector.

    • Genes Locus Forward primers (5'→3') Reverse primers (5'→3')
      ABCB4 Solyc02g087870.2.1 CTACTATACAAATCCCGCAA TGCCAACATCATCCTCCGAA
      ABCB8 Solyc03g114950.2.1 AACCGTTCTTGTCATAGC GTCATCATGTGTGCCACT
      ABCB11 Solyc04g010310.2.1 CGTTCAATCTGCAAATCGGAA AAACTCACTGTTAGGACGACT
      ABCB15 Solyc06g009290.2.1 GGCTTTTGATGGGGGCATTG GATTTTCGCGTAGAGGGCCT
      ABCB18 Solyc06g009290.2.1 AACAAGCCTGAAATACCTG GAAGGCAATAAAAGTTACA
      ABCB20 Solyc09g008240.3.1 TCTTCATACGGTCGATCACC CGGCCAAACGAACTAGCTTG
      ABCB22 Solyc09g055350.2.1 GCCAGAATTATAAGCACTCT CATTCACAACCTTTGCACCA
      ABCB26 Solyc12g098840.3.1 GCATCTTTACTAGCGACACC TCTCCAATCATACCTCGGAC
      Ubiquitin Solyc10g005560.2.1 CACCAAGCCAAAGAAGATCA TCAGCATTAGGGCACTCCTT

      Table 1. 

      Primers used in RT-qPCR analysis

    • Gene Name Gene ID AA MW (kD) pI Instability index Aliphatic index Structural model
      SlABCB1 Solyc02g071340.1 1,264 137.7 5.84 35.80 103.71 Whole-molecular transporter
      SlABCB2 Solyc02g071350.2 1,264 137.1 8.09 35.41 103.32 Whole-molecular transporter
      SlABCB3 Solyc02g087410.2 1,263 137.5 7.97 40.60 99.70 Whole-molecular transporter
      SlABCB4 Solyc02g087870.2 1,250 136.1 8.08 36.86 99.42 Whole-molecular transporter
      SlABCB5 Solyc03g005860.2 1,260 136.7 7.20 36.03 105.92 Whole-molecular transporter
      SlABCB6 Solyc03g093650.2 1,228 134.3 8.35 33.30 102.94 Semi-molecular transporter
      SLABCB7 Solyc04g010310.2 1,286 142.3 6.33 46.36 101.18 Whole-molecular transporter
      SLABCB8 Solyc06g009280.1 1,290 139.3 7.80 36.82 101.57 Whole-molecular transporter
      SLABCB9 Solyc06g009290.2 1,401 138.6 8.18 35.65 100.28 Semi-molecular transporter
      SLABCB10 Solyc06g072960.1 1,029 113.1 7.01 38.56 104.26 Semi-molecular transporter
      SLABCB11 Solyc07g018130.1 1,276 140.2 8.73 36.13 101.71 Semi-molecular transporter
      SLABCB12 Solyc07g064120.1 1,260 138.0 8.88 37.83 93.87 Semi-molecular transporter
      SLABCB13 Solyc08g076720.2 1,258 138.2 8.75 35.64 103.51 Semi-molecular transporter
      SLABCB14 Solyc09g008240.2 1,315 140.0 8.63 36.18 95.56 Whole-molecular transporter
      SLABCB15 Solyc11g067310.1 1,290 141.4 7.05 35.48 103.07 Whole-molecular transporter
      SLABCB16 Solyc12g098840.1 1,281 138.6 6.38 34.90 101.88 Semi-molecular transporter
      SLABCB17 Solyc12g098870.1 1,313 142.72 6.76 37.95 100.58 Whole-molecular transporter
      SLABCB18 Solyc11g067300.1 1,261 138.47 7.50 32.90 102.02 Whole-molecular transporter
      SLABCB19 Solyc05g013890.1 955 105.16 9.10 43.42 96.12 Whole-molecular transporter
      SLABCB20 Solyc03g026310.2 664 67.51 8.94 41.69 102.73 Whole-molecular transporter
      SLABCB21 Solyc03g114950.2 639 68.34 8.45 36.24 104.42 Semi-molecular transporter
      SLABCB22 Solyc03g122050.1 673 74.69 7.34 34.75 80.97 Semi-molecular transporter
      SLABCB23 Solyc03g122070.1 667 73.02 9.45 38.67 101.94 Whole-molecular transporter
      SLABCB24 Solyc09g009910.2 640 71.08 9.14 34.76 113.40 Whole-molecular transporter
      SLABCB25 Solyc09g055350.2 726 80.37 9.40 28.52 98.52 Semi-molecular transporter
      SLABCB26 Solyc00g304030.1 1,081 111.53 9.24 44.24 87.73 Whole-molecular transporter
      SLABCB27 Solyc12g049120.1 349 38.62 9.03 41.41 103.68 Quarter-molecular transporter
      SLABCB28 Solyc12g049130.1 108 11.8 8.79 35.36 101.12 Quarter-molecular transporter
      SLABCB29 Solyc12g070280.1 232 25.82 8.63 29.5 113.55 Quarter-molecular transporter

      Table 2. 

      Characterization of SlABCBs protein in tomato

    • Motif number Motif sequence
      Motif 1 AAKLANAHNFISGLPQGYETQVGERGVQLSGGQKQRIAIARAILKNPKILLLDEATSALDAESERIVQEALDR
      Motif 2 EIELKBVYFSYPSRPDVQILNGFSLKIPSGKTVALVGGSGSGKSTVISLJERFYDPQSGZVLJDGVBJKELQLKW
      Motif 3 MVGERGTQLSGGQKQRIAIARAILKBPRILLLDEATSALDAESERIVQEALDRIMINRTTVIVAH
      Motif 4 TVALVGESGSGKSTVISLJZRFYDPDSGEIYJDGIDIRKFNLKWLRQQMGLVSQEPVLFNDTIRENIAYGKEGAAEEE
      Motif 5 AGEKLIRRIRSMMFEKVLRMEIGWFDEEENSSGAJGARLSTDAATVRSLVGDRLALJVQBLATAIVALVIAFIASWRLALVMJAVQPL
      Motif 6 MVNRTTVVVAHRLSTIKGADVIAVIKBGVIVEKGTHDTLLN
      Motif 7 JRQQIGLVSQEPVLFATTIKENIAYGKEDATEEEIKEAIKLANAAKFIDKLPZGLDT
      Motif 8 KVSLKFVYLAIGVGVASFLZVACWTVTGERQASRIRCLYLKSVLRQDIGFFDTZTNT
      Motif 9 GMTLDVIKGBIEFKHVSFAYPTRPDVQILKDLSLTIPAGK
      Motif 10 AYEEASQIANEAVGNIRTVASFSAEEKVLELYK

      Table 3. 

      The sequences of conserved protein motifs in the ABCB gene family of the tomato genome.