With the loss of chemical control options such as Fenthion and Dimethoate for postharvest treatment of horticulture commodities susceptible to fruit fly infestation, it has become even more important to understand how stress-based control techniques such as heat, cold, irradiation and bacteria parasite can be used most effectively for disinfestation. This project aims to explore the stress-induced molecular response of two fruit fly species of horticultural significance, Mediterranean fruit fly (Ceratitis capitata) and Queensland fruit fly (Bactrocera tryoni), by characterising the cellular pathways involved in both overall and stressor-specific responses.

1. biosecurity built on science
PBCRC3149 Molecular basis of
response to post-harvest
treatment stresses
Plant Biosecurity Cooperative Research Centre
Wei Xu, Ph.D.
Murdoch University

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Team Capability
David Eagling (Program Leader)
Murdoch University
Dr. Wei Xu (Functional Genomics, Insect
Molecular Biology)
Prof. Yonglin Ren (Postharvest treatment)
Dr. Kay Anantanawat (Molecular
Entomology and Bioinformatics)
Dr. Antonios Avgoustinos (Insect Genetics)
SARDI
Dr. Kelly Hill (Molecular Entomology)
Dr. Peter Crisp (Fruit fly biology)
Hawkesburry Institute of Environment
Dr. Alexie Papanicolaou (Genomics,
Bioinformatics)
IAEA
Kostas Bourtzis (Fruit fly biology)
Industry Advisor
Kim James

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Objectives
 Identify the effects of post-harvest treatments
to fruit fly cells
 Build biomarkers for different treatments
Specific Aims
1) Identify early response genes when a lethal stress is
applied
2) Characterise their function in stress response, cell
death and resistance

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Long Term goal
Towards more efficient bio-control methods
1. Understand how concurrent stresses can
improve control efficiency.
2. Build methodology and knowledge for other
species and treatment strategies.

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Model system
Ceratitis capitata
(Mediterranean fruit fly)
Bactocera tryoni
(Queensland fruit fly)
Stages: Eggs and Larvae (L1 and L3)

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Experiment Plan
T0 T1 T2
Stressors Recover
Next Generation Sequencing

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Cold and Heat Treatment
Dr. Kay
Anantanawat
CURATIONS_mRNA1521 NPC2 homolog
NCBI2_rna1712 PREDICTED: uncharacterized protein LOC101459691
NCBI2_rna20008 transmembrane 147
NCBI2_rna20059 heat shock 70
NCBI2_rna20060 heat shock 70
NCBI2_rna5626 FAM92A1 isoform X1
NCBI2_rna820 nucleolar 16
NCBI2_rna8180 heat shock 27
NCBI2_rna8409 MAK16 homolog
NCBI2_rna8490 thiamin pyrophosphokinase 1 isoform X1
NCBI2_rna8953 DNA-binding RFX2
NCBI2_rna9453 leucine-rich repeat 1 (cell death)
NCBI2_rna959 tigger transposable element-derived 1-like
NCBI2_rna11308 OCIA domain-containing 1
NCBI2_rna14874 elongation of very long chain fatty acids AAEL008004
NCBI2_rna16681 heat shock 68
Identified 16 Candidate Genes in Medfly Heat (T1 vs T0)
Dr. Amanda Choo
CRISPR, gene mutate/knock out
Identified 77 Candidate Genes in Medfly Heat (T2 vs T0)

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Irradiation
IAEA
gamma cell 2000 irradiator

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Egg Radiation Treatment
Medfly
0
5
10
15
20
25
30
35
40
45
50
0Gy 10Gy 20Gy 30Gy 40Gy 50Gy 60Gy 70Gy 80Gy 90Gy 100Gy
0
5
10
15
20
25
30
35
40
45
50
0Gy 0Gy 10Gy 20Gy 30Gy 40Gy 50Gy 60Gy 70Gy 80Gy 90Gy 100Gy
Eggs
Egg_hatch
Dead_L1
Pupation
Live_Pupae
Adults_emerged
Males
Females
Adults_DNE
Qfly

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Summary of Irradiation Treatment
1. Eggs (0-200 Gy): Qfly more resistant, Low doses of up to
20 Gy are enough to prevent adult emergence.
2. L1: up to ~150 Gy do not seem to affect the pupation
percentages severely.
3. L3: low doses ranging between 10-40Gy, lead to total
prevention of adult emergence.
4. Collection of samples for RNA extraction to discover WHY

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Cold Treatment on Medfly in Blue Berry
Mean number of pupae, adults, females, males and
incompletely emerged flies from control and cold
treated eggs at 0℃ in cold room 6.

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Genome Work
Funded by US government
co-ordination from Al Handler (ARS-USDA)
Alexie Papanicolaou

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Acknowledgements
PBCRC is established and supported under
the Australian Government Cooperative
Research Centres Programme
 Please email W.Xu@murdoch.edu.au
Collaborations are welcome!