Weeds, which have long been a problem in agriculture, are managed manually,
mechanically, as well as by using chemicals. However, chemical control
options are dwindling due to the rise of herbicide-resistant weeds in
fields. Devendra Pandeya and Damar L. López-Arredondo from Texas A&M
University and StelaGenomics México, respectively, led a team of researchers
to develop an alternative weed control system.

Their team developed transgenic cotton (Gossypium hirsutum) plants
expressing the bacterial phosphite dehydrogenase (ptxD) gene, which confers
the ability to convert phosphite (Phi) into orthophosphate (Pi), the
metabolizable form of phosphorus (P). When P is supplied in the form of Phi,
the ptxD-expressing cotton plants outcompete different weed species
intentionally introduced in the experiments, as well as weeds naturally
present in the tested soils. Furthermore, the ptxD/Phi system was highly
effective in inhibiting the growth of the glyphosate-resistant Palmer
amaranth.

With several weed species having resistance to currently available
herbicides, these ptxD-transgenic plants fertilized with Phi presents an
effective alternative for suppressing weed growth.



[www.pnas.org]