Table 3.

Conservation analysis of the four bidirectional promoters in gramineous plants.

	Oryza sativa	Sorghum bicolor	Setaria italica	Brachypodium distachyon	Zea mays	Triticum aestivum
BIP1	C/C, c-BIP	C/C, c-BIP	C/C, n-BIP	C/C, c-BIP	C/C, c-BIP	C/C, n-BIP
BIP2	C/C, c-BIP	C/C, n-BIP	C/C, n-BIP	C/C, n-BIP	C/C, n-BIP	C/C, c-BIP
BIP3	C/C, c-BIP	C/C, c-BIP	C/C, c-BIP	C/C, c-BIP	C/C, n-BIP	C/C, n-BIP
BIP4	C/C, c-BIP	C/C, c-BIP	C/C, c-BIP	C/C, n-BIP	C/C, n-BIP	C/C, n-BIP

If 5′ gene/3′ gene of the bidirectional promoters had homologous gene in another species (C/C) and the homologous genes were still arranged in bidirectional architecture, they were considered to be regulated by conserved bidirectional promoters (c-BIP). Otherwise, they were considered to be regulated by non-conserved bidirectional promoters (n-BIP).