Emily Chan
Furthermore, the research team noticed that the root and trichome acylsugar genes were gathered close together on the tomato genome, a type of genomic organization known as biosynthetic gene cluster.
“Alongside the aboveground acylsugar pathway we’ve been studying for years, here we find this second parallel universe that exists underground,” Robert Last, the lead study author and a researcher at MSU, said.
ASAT1-L most likely emerged when the ASAT1 gene got duplicated. Once that happened, the two genes split off and specialized for roots and trichomes.
The scientists even examined tomato relatives and found that ASAT1-L and root acylsugars were present in some wild tomato species but not distant cousins such as eggplant.
This indicates that the ability to make root acylsugars was a more recent evolutionary development in the tomato family tree.
Currently, the exact purpose of root acylsugars is unclear. The underground metabolites are similar to trichome compounds, so perhaps they help tomatoes protect themselves against pests and pathogens that live in the soil.
Another possible function is that they aid in drawing beneficial microbes to the roots. Further studies are needed to shed light on their roles.
The findings were published in the journal Science Advances.
