Rothamsted Researchwhere knowledge grows

Applications of understanding insect chemical ecology

PROF TOBY BRUCE

Chemical Ecology

Chemicals that insects use to communicate with each other, and

sense the world around them…

OCOC3H7

OCOC3H7

Collection of volatiles

(Headspace sampling)

Bioassay (naturals)

GC linked electrophysiology

GC-MS identification of biologically relevant compounds

Field testing (trapping experiments or plot trials)

Bioassay (synthetics)

Chemical Ecology

VOLATILE COLLECTION

Collection of volatiles

(Headspace sampling)

Bioassay (naturals)

GC linked electrophysiology

GC-MS identification of biologically relevant compounds

Field testing (trapping experiments or plot trials)

Bioassay (synthetics)

Chemical Ecology

BIOASSAY

insect released in the centre

Record time spent in different parts

Record flight / settlement on target

Olfactometer

Wind-tunnel

Collection of volatiles

(Headspace sampling)

Bioassay (naturals)

GC linked electrophysiology

GC-MS identification of biologically relevant compounds

Field testing (trapping experiments or plot trials)

Bioassay (synthetics)

Chemical Ecology

GC-EAG RECORDING

Collection of volatiles

(Headspace sampling)

Bioassay (naturals)

GC linked electrophysiology

GC-MS identification of biologically relevant compounds

Field testing (trapping experiments or plot trials)

Bioassay (synthetics)

Chemical Ecology

How can we use this?

“High yielding varieties”

NEW SOLUTIONS ARE NEEDED!

MONITORING SYSTEMS

Orange wheat blossom midge

Bruce et al. (2007) Pest Man. Sci. 63: 49

OCOC3H7

OCOC3H7

2,7-nonanediyl dibutyrate

Using the smell of sex!

Decision support system for OWBM

Bruce & Smart (2009) Outlooks Pest Management 20: 89-92

PUSH-PULL

maize yields up from 1 t/ha up to 3.5 t/ha

achieved with minimal inputs to date adopted > 90,000 smallholder farmers in East Africa

“Push-Pull”

1= (E)-ß-ocimene; 2= α-terpinolene; 3= β-caryophyllene; 4= humulene; 5= (E)-4,8-dimethyl-1,3,7-nonatriene; 6= α-cedrene; 7= hexanal; 8= (E)-2-hexenal; 9= (Z)-3-hexen-1-ol; 10= (Z)-3-hexen-1-yl acetate ; 11= 5,7,2 ,4 -tetrahydroxy-6-(3-methylbut-2-′ ′

enyl)isoflavanone (uncinanone A); 12= 4 ,5 -dihydro-5,2 ,4 -trihydroxy-5 -′′ ′′ ′ ′ ′′

isopropenylfurano-(2 ,3 ;7,6)-isoflavanone ′′ ′′(uncinanone B);

13= 4 ,5 -dihydro-2 -methoxy-5,4 -dihydroxy-5′′ ′′ ′ ′ ′-isopropenylfurano-(2 ,3 ;7,6)-isoflavanone ′ ′′ ′′

(uncinanone C), and 14= di-C-glycosylflavone 6-C-α-L-

arabinopyranosyl-8-C-β-D-glucopyranosylapigenin.

Khan et al. (1997) Nature 388: 631-632Khan et al. (2010) J. Exp. Bot. 61: 4185

“Push-Pull”

PLANTS THAT RESPOND BETTER (INDUCED DEFENCE)

0

10

20

30

40

50

60

70

-1 4 9 14 19 24

time after release (h)

% s

ettle

men

t

controlcis-jasmone

cis-jasmone

O

Bruce et al. (2003) Pest Management Science 59: 1031 – 1036

O

0

0.2

0.4

0.6

0.8

1

1.2

28-May 8-Jun 16-Jun 24-Jun 6-Jul

Mea

n N

o. A

phid

s / T

iller

*

*

control

cis-jasmone

P = 0.036

Bruce et al. (2003) Pest Management Science 59: 1031 – 1036

cis-jasmone

Arabidopsis - Myzus persicae – Aphidius ervi

Bruce et al. 2008 PNAS 105: 4553-4558

MI PS Nr. Putative function Log2(R/G) At5g22140 Putative protein -2 At2g44130 F-box protein -1.83 At2g04870 Hypothetical protein -1.61 At1g21310 Hypothetical protein -1.44 At3g28740 Cytochrome P450 -1.42 At1g55920 Serine acetyltransferase -1.4 At5g44030 Cellulose synthase catalytic subunit -like -1.4 At2g28330 Hypothetical protein -1.34 At3g05110 Hypothetical protein -1.32 At1g78380 Glutathione S-transferase, similar to -1.32 At2g29490 Putative Glutathione S-transf erase -1.29 At1g55920 Serine acetyltransferase -1.28 At5g24610 Putative protein -1.28 At5g14730 Putative protein -1.27 At4g39290 Putative protein -1.27 At5g21940 Putative protein -1.26 At1g78380 Similar to glutathione S-transf erase -1.25 At1g21310 Hypothetical protein -1.24 At1g69980 Hypothetical protein -1.23 At3g16920 Basic chitinase, putative -1.22 At4g12470 pEARL 1-like protein -1.2 At3g13750 Galactosidase putative -1.19 At1g76690 12-oxophytodienoate reductase (OPR1/ 2) -1.19 At3g25910 Unknown protein -1.18 At3g02300 Unknown protein/ chromatin modification -1.17 At1g07920 Elongation f actor 1-alpha -1.17 At4g12000 Putative protein -1.15 At1g09500 Putative cinnamyl alcohol dehydrogenase -1.12 At3g09270 Glutathione transf erase -1.11 At4g30920 Leucyl aminopeptidase like -1.11 At1g32940 Hypothetical protein -1.09 At1g21310 Hypothetical protein -1.08 At5g15630 Phytochelatine synthase, putative -1.08 At4g02520 Atpm24.1 glutathione transf erase -1.07 At1g17860 Hypothetical protein -1.06 At1g48090 Unknown protein -1.05 At4g21130 Hypothetical protein -1.04 At3g08790 Hypothetical protein -1.04 At2g18190 Putative AAA-type ATPase -1.04 At1g35580 I nvertase, putative -1.02 At3g13310 DNAJ protein, putative -1.01 At4g26050 Putative leucine rich repeat protein -1

upregulated genes: OPR1/2

Cell wall biosynthetic genes

Cytochrome P450 (CYP81D11)

F-box containing protein

Sequences unaffected by cis-jasmone:

Defence genes (PR proteins, etc)

Stress genes (HSPs, etc)

Jasmonate-regulated genes (OPR3, LOX)

cis-jasmone

Myzus persicae responses to CYP81D11 overexpressing plants

Bruce et al. 2008 PNAS 105: 4553-4558

Aphidius ervi responses to CYP81D11 overexpressing plants

Bruce et al. 2008 PNAS 105: 4553-4558

EGG ALERT

HYPOTHESIS: Landraces are MORE RESISTANT TO STRESSES such as stemborer attack…

are parasitoids more attracted to HIPVs from landraces?

±

24h

Bioassay of response to volatiles from plants WITH and WITHOUT eggs

Tamiru et al. (2011) Ecology Letters 14: 1075

Parasitoid response - landraces

ATTRACTED to plants with eggs

Volatile profiles - landraces

(a) (E)-ocimene, (b) (R)-linalool, (c) (E)-4,8-dimethyl-1,3,7, nonatriene (DMNT), (d) methyl salicylate, (e) decanal, (f) methyleugenol, (g) (E)-(1R,9S)-caryophyllene, (h) (E)-β-farnesene, (i) (E,E)-4,8,12-trimethyl-1,3,7,11-tridecatetraene (TMTT).

Tamiru et al. (2011) Ecology Letters 14: 1075

INDUCTION with plants with eggs

IMPROVING BIOCONTROL

New Agri-tech Catalyst project: Lure-and-kill technology to manage beetle pests of field beans and peas

4-Methylheptane-3,5-dione

Beauveria bassiana spores adhering to Entostat particles

Sitona lineatus adults

♂ produced aggregation pheromone that attracts ♀s and ♂s

Flight is not an option for plants !

Labandeira (2013) Curr. Opin. Plant Biol. 16: 414

400 Million years of Coevolution

Innovation in crop protection is very much needed as conventional pesticides are lost to resistance or banned

Perhaps an understanding of chemical ecology can help ?