Molecular interactions between the olive and the fruit fly Bactrocera oleae.
BACKGROUND
The fruit fly Bactrocera oleae is the primary biotic stressor of cultivated olives, causing direct and indirect damages that significantly reduce both the yield and the quality of olive oil. To study the olive-B. oleae interaction, we conducted transcriptomic and proteomic investigations of the molecular response of the drupe. The identifications of genes and proteins involved in the fruit response were performed using a Suppression Subtractive Hybridisation technique and a combined bi-dimensional electrophoresis/nanoLC-ESI-LIT-MS/MS approach, respectively.


RESULTS
We identified 196 ESTs and 26 protein spots as differentially expressed in olives with larval feeding tunnels. A bioinformatic analysis of the identified non-redundant EST and protein collection indicated that different molecular processes were affected, such as stress response, phytohormone signalling, transcriptional control and primary metabolism, and that a considerable proportion of the ESTs could not be classified. The altered expression of 20 transcripts was also analysed by real-time PCR, and the most striking differences were further confirmed in the fruit of a different olive variety. We also cloned the full-length coding sequences of two genes, Oe-chitinase I and Oe-PR27, and showed that these are wound-inducible genes and activated by B. oleae punctures.


CONCLUSIONS
This study represents the first report that reveals the molecular players and signalling pathways involved in the interaction between the olive fruit and its most damaging biotic stressor. Drupe response is complex, involving genes and proteins involved in photosynthesis as well as in the production of ROS, the activation of different stress response pathways and the production of compounds involved in direct defence against phytophagous larvae. Among the latter, trypsin inhibitors should play a major role in drupe resistance reaction.
Dipartimento di Scienze del Suolo, Pianta, Ambiente e Produzioni Animali, Universita' degli Studi di Napoli Federico II, Via Università 100, Portici, Napoli 80055, Italy.
Giandomenico
G
Corrado
Fiammetta
F
Alagna
Mariapina
M
Rocco
Giovanni
G
Renzone
Paola
P
Varricchio
Valentina
V
Coppola
Mariangela
M
Coppola
Antonio
A
Garonna
Luciana
L
Baldoni
Andrea
A
Scaloni
Rosa
R
Rao
D000595:Amino Acid Sequence; D000818:Animals; D019295:Computational Biology; D020224:Expressed Sequence Tags / Q000378:metabolism; D018506:Gene Expression Regulation, Plant; D017343:Genes, Plant; D060434:Herbivory; D008969:Molecular Sequence Data; D031658:Olea / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D010788:Photosynthesis; D020543:Proteome / Q000032:analysis; D017382:Reactive Oxygen Species / Q000378:metabolism; D060888:Real-Time Polymerase Chain Reaction; D016415:Sequence Alignment; D015398:Signal Transduction; D013312:Stress, Physiological; D033621:Tephritidae / Q000502:physiology*; D059467:Transcriptome
D020543:Proteome; D017382:Reactive Oxygen Species