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Grass endophytes for insect management
and improved pasture productivity
John Caradus
On behalf of a very big team of people
Content
1. What are fungal endophytes?
2. What is the biocontrol issue?
3. What has been achieved?
4. How was this achieved?
5. What is next – other uses of endophytes?
1. What are fungal endophytes?
Fungal endophyte + Grass Plant
Endo = within - Phyte = plant
Each green dot is a hypha of an endophyte expressing
a green florescent protein
Endophyte lifecycle
Diversity in endophytes
• Neotyphodium fungal endophytes are not all the same, there is considerable diversity in their biochemical profiles
• Europe has a wide diversity of grass endophytes
• AgResearch has the largest collection of grass
endophytes in the world
• New Zealand is the recognised world leader in
grass endophyte technology and its
commercialisation
What fungal endophytes do ?
• Protect host plants against biotic and abiotic stresses
• Biotic stress protection
– Insects
– Nematodes
– Plant pathogens
• Abiotic stress protection
– Drought
• Protection increases plant production and persistence
Endophyte chemistry
• Endophytes are all about chemistry
• They produce a range of bioactive
secondary metabolites (alkaloids)
• The type of alkaloids produced depends
on the strain of fungus present
• The host plant has a major effect on the
quantity of alkaloids
• The chemistry of endophytes is diverse
and complex
Endophyte alkaloids
• Four main groups identified
– Peramine
– Ergovaline
– Indole diterpenoids
• Lolitrems
• Epoxy janthitrems
– Lolines
• All are active against insects
– Toxic
– Deterrent
• Unknowns
Basic science
• Understanding the life cycle of Neotyphodium
endophytes
• Isolation from grasses and growth ex plant
• Inoculations challenges – into the plant
• Transmission challenges – into the seed
• Understanding the chemistry – discovering
unknown alkaloids
• Understanding the genes controlling alkaloid
expression
• Endophyte viability in seed
2. What is the biocontrol issue?
Pests of endophyte-free ryegrass
• Porina
• African black beetle
• Argentine stem weevil
• Pasture mealy bug
• Grass grub
• Root aphid
Ryegrass + Endophyte Ryegrass – Endophyte
Meadow fescue + Endo Meadow fescue – Endo
Tall fescue + with Endophyte Tall fescue – minus Endophyte
Tall fescue at Bega, NSW, Australia
But….
• While endophytes alkaloids do have powerful
insecticidal properties some can also have
serious affects on ruminants
Ergovaline - a vaso-constrictor that causes heat stress,
and reduces live weight gains and serum prolactin
Lolitrem B - a tremorgen that causes the neuro-muscular
disorder ryegrass staggers
Epoxy janthitrems - a tremorgen
• It is a case of balancing the upside of insect
resistance with the downside of animal health
and welfare
Ryegrass staggers!
3. What has been achieved?
Tall FescueEndophytes
Ryegrass Endophytes
ENDO 5
1
Timeline for
ryegrass endophyte
understanding and
development
Endophyte linked with
- insect resistance
- ryegrass staggers, then production
1980
1992 First novel endophyte released –partially withdrawn
AR1 novel endophyte2000
2007 AR37 novel endophyte
2010 >80% seed sales of proprietary cultivars have novel endophytes
1980 - 90 Development of High Endophyte lines (containing a wild-type endophyte)
2003 NEA2 novel endophyte
2011- 2020 Novel endophytes with better insect resistance and drought tolerance
2006 Endo5 novel endophyte
Ryegrass endophyte
1
AR1 endophyte
• Ryegrass endophyte that does not cause
ryegrass staggers but provides Argentine stem
weevil resistance
• Non-exclusive release
• Initially targeted for Australasia
• Uptake rate has been high
AR1 - Pastoral industry benefits
AR1 a technological breakthrough
Prevents ryegrass staggers
Does not cause heat stress
Reduces fly strike
Increases live weight gain >10%
Increases milk solids 9%
Lamb responses to grazing Nui ryegrass with AR1
endophyte in summer and autumn. Means of 3 years
Values within a column with a letter subscript in common are not significantly different
* LWG = Live weight gain, Resp = respiration, PRL = prolactin, RGS = ryegrass staggers
Ryegrass
cultivar +
endophyte:
LWG *
g/hd/day
Rectal
tempO C
Resp
rate
/min
PRL
Ng/ml
RGS
0-5
scale
Dags
0-5
scale
Nui wild-type 23 a 40.5 a 97 a 96 a 3.2 a 0.6 a
Nui nil 120 b 40.0 b 73 b 185 b 0 b 0.2 b
Nui AR1 131 b 40.1 b 79 b 203 b 0 b 0.3 b
Ryegrass endophyte
37
AR37
Aorangi (Manawatu) April 1999
AR37(left) versus existing pasture
Photo taken at AgResearch Farm at Tokonui - 29 February 2008
Comparisons
AR37AR1
StandardEndophyte-free
Argentine stem weevil
Manawatu Kerikeri Waikato
Nil 20 36 63
AR1 8 6 17
AR37 4 4 18
Standard 7 5 28
P<0.05 P<0.05 P<0.05
National Evaluation Field Trials 1997 & 1998
Percent tillers with larval damage
Black Beetle - Larval Numbers
0
20
40
60
80
100
120
140
No
. la
rvae/m
2
Nil Std AR37AR1 Nil Std AR37AR1
Year 1 Year 2
Porina – Plant Damage
0
2
4
6
8
10
12
14
2 4 6
Week
Cu
mu
lati
ve d
am
ag
e
Nil Standard AR37
0
5
10
15
20
25
1 2 3 4 5
Week
Nil Standard AR37
Trial 1 Trial 2
Pasture Mealy bug – Field Trial
0
2
4
6
8
10
12
14
16
18N
o.
mealy
bu
g/c
ore
Nil Std AR37 AR1
Root Aphids – Pot Trial
0
50
100
150
200
250
300
Mean
No
./P
lan
t
April Sept Jan May
Nil Standard AR37
Issues with AR37
• Grass staggers can be experienced with AR37 –
these are short lived and not normally as severe
as those experienced on wild type endophyte.
Recommendation:
• If AR1 persists on your farm then sow AR1
• If AR1 does not persist then sow AR37 – not
high endophyte wild type.
Tall fescue Endophyte
Case study – into the USA
Fescue toxicosis in cows - caused by
toxic endophytePregnancy rate reduced up to 37%
Abortion during early pregnancy
Calf deaths up to 20% after birth
Calving reduced from 78-95% to 49-74%
Intolerant to heat
Grazing time reduced 20 - 90%
Forage intake reduced 40%
Milk production reduced 37 - 60%
Weaning weights of calves reduced 14%
Endophyte-infected tall fescue can
cause serious problems with cattle
The alkaloid ergovaline results in damaging
elevated body temperatures
MaxQ endophyte
• Tall fescue non-toxic endophyte identified
for USA
• Patent protection of IP
• Exclusive license for defined period
• Marketing as an added value products
• Improved plant persistence without
causing any adverse animal effects
No
endophyteMaxP MaxP
The benefits of MaxQ
• Compared to Kentucky 31 (contains toxic endophyte) tall
fescue pastures in USA, the benefits of MaxQ pastures for
pasture-finished beef are:
Removes toxic alkaloids from meat and fat
Increases calf numbers (+ 20 to 50 %)
Increases milk production
Increases weaning weights (+ 15 %)
Reduced number of days for steers to reach target weights (- 60%)
Heavier live weight of feeder cattle per acre (+ 140%)
Heavier carcass weights (+ 10%)
Increased value of beef produced (+ 9%)
Wild, toxic endophyte in
Jesup TALL FESCUEAR542 endophyte in
Jesup TALL FESCUE
Lamb Safety Study at Eatonton, Georgia, USA
4. How was all of this achieved?
+
Understanding the process
Grass
Fungus
Chemistry
Insects
Successful ingredients
• A great R&D team – multi-disciplined approach
and very good science
• Strong international links
• Strong links to NZ industry – supported
financially by seed companies and Beef and
Lamb (when it was Meat and Wool)
• Strong commercialisation drive through
Grasslanz Technology Ltd and commercial
partners
The Grass Endophyte R&D Team
• Garry Latch
• Mike Christensen
• Syd Easton
• David Hume
• Alison Popay
• Brain Tapper
• Lester Fletcher
• Sarah Finch
• Wade Mace
• Chris Pennell
• Geoff Lane
• Lynn Briggs
• Wayne Simpson
• Stuart Card
• Phil Rolston
• Lee Sutherland
• Bruce Cooper
• Jason Trethewey
• Heike Schwendel
• Marty Faville
• Jana Schmidt
• Anouck de Bonth
• Joanne Jensen
• And others
Mycologists
Animal scientists
Seed scientists
Agronomists
Chemists
Plant scientists
Entomologists
Endophyte
Knowledge
Multidisciplinary
approach
5. What is next – other uses of
endophytes?
Current opportunities
• Wildlife deterrence
• Endophyte in cereals
• Pesticidal extract
Cafeteria Seed Feeding
0
10
20
30
40
50
60
70
80
90
100
NIL ENDO NOVEL A NOVEL B
Treatments
Gra
ms
Co
ns
um
ed
“Learned geese”
Aphids on roses
Natural pesticide treated Control
Fungal endophytes
• A very successful method of biocontrol that is
seed transmitted
• Based on excellent science
• Commercially successful and is being widely
used
With endophyte Without endophyte