Genomes of Poaceae sisters reveal key metabolic innovations preceding the emergence of grasses

Abstract

The grass family (Poaceae, Poales) holds immense economic and ecological significance, exhibiting unique metabolic traits, including dual starch and lignin biosynthetic pathways. To investigate when and how the metabolic innovations known in grasses evolved, we sequenced the genomes of four Poales species, including Joinvillea ascendens and Ecdeiocolea monostachya representing the sister clade to Poaceae. The rho whole genome duplication ({rho}WGD) in the ancestral lineage for all grasses contributed to the gene family expansions underlying cytosolic starch biosynthesis, whereas an earlier tandem duplication of phenylalanine ammonia lyase (PAL) gave rise to phenylalanine/tyrosine ammonia lyase (PTAL) responsible for the dual lignin biosynthesis. Integrated functional genomic and biochemical analyses of grass relatives further revealed the molecular basis of key metabolic innovations predating the evolution of grasses. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=149 SRC="FIGDIR/small/622220v2_ufig1.gif" ALT="Figure 1"> View larger version (108K): org.highwire.dtl.DTLVardef@117dd71org.highwire.dtl.DTLVardef@1cb5daborg.highwire.dtl.DTLVardef@72a331org.highwire.dtl.DTLVardef@38124e_HPS_FORMAT_FIGEXP M_FIG C_FIG