Scientists are delving deep into the science of endophytes, the naturally occurring fungi that live on a plant for part of its life, to help arable and horticulture crops.
It is an area AgResearch holds significant knowledge and expertise in and intellectual property over, thanks to this country’s focus on improving pastoral productivity through discovering better endophytes.
“The AR37 endophyte commercialised in 2007-08 has proven to be a ground-breaking endophyte in terms of its ability to naturally control five key pastoral pests, with minimal animal health implications.
“While there have been incidences of staggers found in sheep grazing on it, the advantages it has brought have well outweighed those risks and made it the first choice for farmers seeking more productive pasture in areas with significant insect pest pressure.”
Those advantages have been valued at about $3.66 billion for the 20 years of AR37’s patent protected period, about $200 million a year.
“This comes in terms of increased pasture productivity compared against all endophytes on the market and better animal performance on these grasses compared to standard endophyte.”
The AR37 discovery was somewhat serendipitous.
It was being used in trials as a control endophyte only for researchers to discover it delivered outcomes well in excess of those endophytes actually being tested.
As an Epichloe endophyte, it is one of a group that are naturally grass sourced.
But the researchers in Palmerston North, Hamilton and Christchurch hope they might yet prove to have a growth-promoting or disease prevention role in the cousins to ryegrass.
Sorting the wheat from the chaff in the endophyte world first involves determining which carry the toxic compounds that cause heat stress and staggers and dropping them straight off.
“Not all researchers will discard an endophyte on these grounds but we maintain this as a bottom line for starting from,” Johnson said.
However, there is a need to better understand how other compounds in endophytes give benefits to plants and possibly their animal consumers to make finding them less like a needle in a haystack.
“If we do it for maize, we could then do it for other crops.”
Dr Linda Johnson
AgResearch
The researchers have received Ministry for Business, Innovation and Employment and commercial funding to study endophytes for cereal crops including wheat, triticale and rye from the genus Elymus found in grasslands throughout the world.
“Using the same chemical screening we have done here for grasses we are able to take endophytes from them, isolate them, culture them and artificially inoculate them into a cereal germplasm.”
Initial results proved inoculation with a non-host endophyte was problematic.
Researchers have worked to understand why an endophyte from wild grasses might struggle to associate with wheat or rye.
“But we have got to the point where we are now enjoying some success.
“That includes the endophyte being passed on to the next generation through seed.”
Researchers are running trial crops at Lincoln to study the possible gains in crop productivity resulting from endophyte infection.
Johnson hopes further work will determine to what extent the new endophytes fall into the category of endophyte bio-controls that control pests in the same way AR37 does and which might even be endophyte bio-stimulants that boost plant productivity.
“At this stage it appears their role is in that first area. They make an array of compounds to protect the plant.”
They also hope other endophytes with a wide host range might not need to be passed on through seed as their only means of being effective or sustained and could be applied as a treatment to the seed or plant.
As global pasture and crop land faces the pressure of producing more for a growing population while cutting fertiliser and spray use, endophytes might hold some answers.
The team has also been asked to contribute its knowledge to isolating endophytes in Brachiaria, a highly productive sub-tropical grass.
“We came across an endophyte that proved useful against diseases in the plant and hope to progress it further here.”
A study of heritage maize varieties from Mexico also hopes to identify endophytes that might have been lost as those varieties fell out of commercial favour or never qualified.
“We aim to build up a heritage collection of endophytes, rediscovering what has potentially been lost over the years.
“If we do it for maize, we could then do it for other crops.”
Estimates are that reducing the most common diseases and insects from NZ maize crops could itself repay the industry in savings and productivity gains of $24 million a season.
“And as we see more pesticide types are banned, endophytes may provide a viable alternative to preserving crop quality and productivity in the future.
“The qualifier is that these take time to develop.
“They may also have potential in other areas including improving nutrient availability and the possibilities lie beyond agriculture, in horticulture too.”
