Comparative genomic analysis of the R2R3 MYB secondary cell wall regulators of Arabidopsis, poplar, rice, maize, and switchgrass

Table 3 Subgroups of R2R3 MYB proteins from Arabidopsis (At), poplar (Ptr), rice (Os), maize (Zm) and switchgrass (Pv) defined by neighbor-joining phylogenetic reconstruction

Sub-group^a	Subgroup distribution^b	Bootstrap score	At	Ptr	Os	Zm	Pv	Previous C-terminal motif identification^c	Names of SCW regulators (AtMYB#)
G1	Panicoid-Expanded^d	66	5	4	7	12	14	I	0
G2	ND^e	37	3	4	3	5	8	P	0
G3.a	ND^e	3	4	2	1	1	2	P	58, 63
G3.b	Grass-Expanded	46	0	0	2	5	6	N	0
G4	ND^e	14	6	7	8	10	22	I	5
G5	ND^e	13	1	9	2	2	1	N	0
G6	Dicot-Expanded	7	4	8	0	0	0	I	75
G7	ND^e	17	2	1	2	5	4	N	0
G8	ND^e	89	4	6	5	8	17	P	20, 43, 42, 85
G9	ND^e	51	2	4	3	4	7	P	0
G10	Dicot-Expanded	100	2	3	0	0	0	P	0
G11	ND^e	92	4	6	1	2	0	I	0
G12	Arabidopsis-Specific	26	6	0	0	0	0	I	0
G13.a	ND^e	21	1	2	1	2	5	P	0
G13.b	ND^e	5	4	7	5	7	10	P	61
G14.a	ND^e	33	2	5	2	2	1	N	0
G14.b	ND^e	43	6	8	8	11	22	N	0
G15	Dicot-Expanded	39	4	5	0	0	0	I	0
G16	ND^e	30	3	2	3	3	8	P	0
G17.a	ND^e	93	2	2	3	5	4	N	0
G17.b	ND^e	86	3	5	3	4	3	P	0
G18	ND^e	7	7	5	2	2	3	N	0
G19	ND^e	59	3	2	1	0	0	N	0
G20	Panicoid-Expansion	88	6	8	5	13	10	I	0
G21	ND^e	20	8	13	5	8	14	I	52, 54, 69
G22	ND^e	62	4	6	3	5	12	P	0
G23	ND^e	98	3	1	1	1	2	N	0
G24	ND^e	88	3	4	3	3	5	I	0
G25	ND^e	29	7	6	5	4	8	I	0
G26	ND^e	80	1	4	2	3	0	N	0
G27	Grass-Expanded	63	0	0	2	3	1	N	0
G28	ND^e	25	1	7	1	1	0	N	0
G29	ND^e	40	2	5	2	2	3	N	26
G30	ND^e	100	1	2	1	1	2	N	103
G31	ND^e	99	2	4	1	1	2	N	46, 83
G32	Grass-Expanded	100	0	0	1	5	1	N	0
G33	ND^e	100	1	3	1	3	4	N	0
G34	ND^e	100	1	3	0	1	0	N	0
G35	Grass-Expanded	42	0	0	2	4	6	N	0
G36	ND^e	25	0	2	2	2	3	N	0
G37	ND^e	100	2	2	1	1	1	N	0
G38	Poplar-Specific	13	0	7	0	0	0	N	0
G39	Poplar-Specific	86	0	3	0	0	0	N	0
G40	Poplar-Specific	100	0	4	0	0	0	N	0
G41	ND^e	100	1	5	7	3	0	N	0
G42	ND^e	100	0	0	1	0	3	N	0
G43	Grass-Expanded	75	0	0	2	1	5	N	0
G44	Rice-Specific	99	0	0	7	0	0	N	0
G45	Grass-Expanded	100	0	0	1	1	3	N	0
G46	Grass-Expanded	97	0	0	2	3	7	N	0
G47		21	0	5	0	1	0	N	0
G48	Poplar Specific	37	0	4	0	0	0	N	0

Assignment to a subgroup is based on the 5-species neighbor-joining tree with 500 bootstraps (Additional file 2: Figure S1).
^bDistribution or expression of each subgroup in the clades examined.
^cC-terminal conserved motifs were analyzed using MEME for each subgroup and compared to known motifs present in the 25 subgroups of Arabidopsis R2R3 MYB family. I: Previously identified; P: Partially previously identified; N: Not previously identified. The last column lists the Arabidopsis (At) secondary cell wall (SCW) regulators by their numeric names.
^dPanicoid-expanded refers to the pattern in maize and switchgrass.
^eND indicates that no subgroup distribution pattern was detected.

ISSN: 1471-2229