Figure 2.

A, Phylogenetic analysis of putative flavonoid regulatory poplar R2R3 MYB domain proteins with selected R2R3 MYB domain proteins from other species. R2R3 MYB domains were aligned using ClustalW, and the phylogenetic tree was constructed using MEGA 3.1 (Kumar et al., 2004) using the minimum evolution test and p-distance model with 1,000 bootstrap replicates. Bootstrap values higher than 50% are shown. Human c-myb and Arabidopsis subgroup G7 MYBs are included as outgroups. The N08, N09, G5, and G20 subgroups of Jiang et al. (2004) are indicated. GenBank accession numbers are as follows: CaA (Capsicum annuum A, AJ608992), LeANT1 (Lycopersicon esculentum [now Solanum lycopersicum] ANT1, AAQ55181), PhAN2 (Petunia × hybrida AN2, AAF66727), VvMYBA1 (Vitis vinifera MYBA1, BAD18977), VvMYBA2 (V. vinifera MYBA2, BAD18978), AtPAP1 (Arabidopsis thaliana PAP1/MYB75, AAG42001), AmVENOSA (Antirrhinum majus VENOSA, ABB83828), AmROSEA1 (A. majus ROSEA1, ABB83826), AtTT2 (Arabidopsis TT2/MYB123, Q9FJA2), ZmC1 (Zea mays C1, AAK09327), ZmPL (Z. mays PL, AAB67721), FaMYB1 (Fragaria × ananassa MYB1, AAK84064), AtMYB4 (Arabidopsis MYB4, NP_850879), Ph4 (Petunia × hybrida PH4, AAY51377), VvMYB5a (V. vinifera MYB5a, AAS68190), PmMBF1 (Picea mariana MBF1, AAA82943), VvMYBPA1 (V. vinifera MYBPA1, AM259485), AtGL1 (Arabidopsis GLABROUS1, P27900), AtMYB23 (Arabidopsis MYB23, NP_198849), AtWER (Arabidopsis WEREWOLF1, NP_196979), and c-myb (Homo sapiens c-myb, AAB49039). B, Alignment of predicted poplar PA regulatory MYB proteins with the Arabidopsis PA regulator TT2, maize PL, and uncharacterized MYB proteins from Oryza sativa (OsMYB3, BAA23339) and Gossypium hirsutum (GhMYB36, AAK19617) containing conserved motifs C terminal to the MYB DNA-binding domain. The residues involved in the interaction with bHLH cofactors are indicated by arrowheads. The gray bar indicates the Vx2IRTKA[IL]RC[SN] motif found in AtTT2 and OsMYB03, and the black bars indicate the R2 and R3 repeats of the MYB domain.