Thursday, July 7, 2022

Iron-grabber vital for grass

AgResearch have discovered what makes endophytes succeed in ryegrass.

In a paper published in the journal PLOS Pathogens, AgResearch science team leader for plant-fungal interactions Dr Linda Johnson describes the tactic used by an endophyte to extract iron from its ryegrass host.

Hidden within ryegrass, lies an invisible helper, an endophytic fungus that protects pastures from being destroyed by unwanted pests, thus increasing pasture production and persistence.

The endophyte produces a small molecule, known as a siderophore, which grabs and binds strongly to iron, an element essential to both the host and fungal partner.

“Eliminating the siderophore caused major problems for both the fungal endophyte and the host grass plant,” Johnson said.

“The usual, tightly controlled, synchronous growth of the fungus inside the ryegrass became deformed and unregulated, the host plants were stunted and in extreme cases both the fungus and host plant died.”

This is the first report that siderophores are essential to the mutually beneficial relationship between ryegrass and endophyte.

Johnson said the relationship is crucial for New Zealand agriculture.

The research is part of a large AgResearch programme to find better endophytes for ryegrass.

“We don’t yet have the best possible endophyte in terms of pest protection, animal safety and host compatibility,” Johnson said.

“We actively look for new endophytes from around the world but to identify better performers that can live in pasture grasses we need to know more about the fungal-host interaction. To do that well, this fundamental research into how grasses and endophytes interact is essential.”

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