Comparison between volatile emissions from transgenic apples and from two representative classically bred apple...

Area of Science:

• Plant science
• Genetics
• Chemical ecology

Background:

• Risk assessments typically compare transgenic crops to isogenic lines.
• A comparison with classically bred cultivars possessing the same resistance gene is valuable for understanding plant-insect interactions.
• Volatile organic compound (VOC) profiles can influence relationships between plants and non-target insects.

Purpose of the Study:

• To compare headspace volatiles of transgenic scab-resistant apple plants with an isogenic line and a classically bred cultivar.
• To investigate the impact of leafminer infestation on VOC emissions in different apple genotypes.
• To assess if differences in VOCs between transgenic and conventional apples are significant in the context of natural variability.

Main Methods:

• Gas chromatography-mass spectrometry (GC-MS) was used to analyze headspace volatiles.
• Transgenic scab-resistant apple plants were compared to an isogenic 'Gala' line and a classically bred 'Florina' cultivar (containing a scab resistance gene).
• Plants were analyzed under both healthy conditions and after infestation with leafminers (Phyllonorycter blancardella).

Main Results:

• Significant quantitative differences in VOC emissions were observed between healthy and leafminer-infested apple genotypes.
• Four terpenes and one aromatic compound showed quantitative variations between the transgenic line and the two cultivars under infestation.
• These observed differences in odour emissions were within the natural range of variability found in the two standard cultivars.

Conclusions:

• The VOC profile differences between transgenic and conventional apples, even under pest infestation, are comparable to the natural variability observed in standard cultivars.
• This suggests that the scent profile modifications in the transgenic line may not represent a significant deviation from conventional breeding outcomes.
• The classically bred cultivars serve as important references for evaluating scent profile changes in transgenic apple research.