Genetic improvement of biocontrol nematodes

Ralf-Udo Ehlers

ehlers@e-nema.de

www.e-nema.de

e-nema GmbH, Schwentinental, Germany

• EPN are used in biocontrol of cryptic insect pest

• E-nema produces the species Heterorhabditis bacteriophora, Steinernema feltiae and S. carpocapsae

• Also produced: yeasts, fungi and bacteria

• Currently 6 industry-scale tanks in production

• Capacity increase in 2017

• Downstream technology and drying facilities

Biocontrol paradigma: Indigenous species/strains are best suited for biological control

Is there scientific evidence ? Yes, for the opposite!

In biocontrol new associations, not sharing a co-evolution, are superior to old associations (Hokkanen & Pimental, 1984 + 1989, Canadian Entomologist).

Host defences coevolve in response to attacks by parasites. The virulence of the parasite in such an association is decreasing and the resistance to parasite attack is increasing resulting in a relatively stable relationship tending to commensalism or mutualism.

New association approach is as safe as old associations in terms of environmental risks.

EPN, for several reasons, are exceptionally safe.

Our approach: Use of classical genetics to improve beneficial traits of EPN

But what about adaptation to local climatic conditions?

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Phenotyping strains for desiccationtolerance. Tolerated water activity after adaptation (Mukuka et al., 2010, Nematology)

From Germany

Why is the nematode Heterorhabditis bacteriophora an excellent target for improvement by breeding?

• It has a 7 day life cycle (Addis et al. 2016)• Can be propagated in vitro in small and large scale (Ehlers, 2001)• Dauer juveniles can be stored in liquid nitrogen• We can cross, because they produce males and females (Johnigk & Ehlers, 1999)• We can also produce highly homozygous inbred line because they also reproduce

through self-fertile hermaphrodites (Johnigk & Ehlers, 1999)• They are closely related to the model nematode Caenorhabditis elegans, we thus can

use genetic information available for this species (Sommer, 2015)

What has been done?

E-nema has available 50 wildtype strains from all over the worldWe have >200 inbred lines and crosses

What has been done?

E-nema has available 50 wildtype strains from all over the worldWe have >200 inbred lines and crossesWe have assessed the heritability of beneficial traits

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What has been done?

E-nema has available 50 wildtype strainsWe have >200 inbred lines and crossesWe have assessed the heritability of traitsMost strains and inbred lines have beenphenotyped for

- desiccation and heat tolerance- longevity and persistence

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Mean Time Survived (MTS) in 40Heterorhabditis bacteriophora wildtype strains at 25°C, Error bars: SDfrom three independent trials (p≤005)

What has been done?

E-nema has available 50 wildtype strains from all over the worldWe have >200 inbred lines and crossesWe have assessed the heritability of beneficial traitsMost strains and inbred lines have been phenotyped for

- desiccation and heat tolerance- longevity and persistence- virulence against 2 insects

What has been done?

E-nema has available 50 wildtype strains from all over the worldWe have >200 inbred lines and crossesWe have assessed the heritability of beneficial traitsMost strains and inbred lines have been phenotyped for

- desiccation and heat tolerance- longevity and persistence- virulence against 2 insects- other traits can be investigated

Crosses have been producedHybrids have been selected for improved performanceGenotypes and expression profiles are analysed

What will we do?

• We will search for genetic markers related to beneficial traits• A marker-associated breeding programme will result in

nematode strains with improved biocontrol characters

Annotation of 22,000 H. bacteriophora transcripts derived from the HU2-IL1 and PT1-IL1 lines under stress

This project has received funding from the European Union’s Seventh Framework Programme

E-nema Team:Nanette Hope Nellas SumayaVerena DörflerMike BargDr. Olaf StrauchDr. Bart VandenbosscheDr. Carlos MolinaDr. Arne PetersDr. Temesgen Addis

Students UGent+UKiel:Christopher OkoloAlejandra CenturionAbdi YaliEdwin TitamohSitaram AryalRiddih GohilOlaniyi OlarewajuJosiane Mukayisenga

Co-operators:Prof. Itamar Glazer, Volcani CenterDr. Dana MentDr. Hadas ShafranProf. Nelson Simoes, UAcores, PORDr. Duarte Toubarro