Efficacy of 2 botanical aphicides, chicoric and 3,5-dicaffeoylquinic acids, on aphids susceptible and resistant to synthetic insecticides.

Dicaffeoyltartaric acid (diCT) and 3,5-dicaffeoylquinic acid (3,5-diCQ) are described for their aphicidal properties on several aphid species. Intending to valorize diCT and 3,5-diCQ as biocontrol products and because of the high adaptive capacities of aphids to xenobiotics, we sought to determine the existence of adaptation first in Myzus persicae (Sulzer) (Hemiptera: Aphididae) and then other aphids. Resistance of aphids to these biopesticides could be promoted by (i) the existence of resistance to synthetic insecticides that may confer cross-resistance and (ii) the presence of these compounds in wild plants likely which may have led to pre-existing adaptation in aphids.

Molecular mechanisms of resistance to conferred by the peach gene: A multi-omics view.

The transcriptomic and metabolomic responses of peach to infestation were studied in Rubira, an accession carrying the major resistance gene causing antixenosis, and GF305, a susceptible accession. Transcriptome and metabolome showed both a massive reconfiguration in Rubira 48 hours after infestation while GF305 displayed very limited changes. The Rubira immune system was massively stimulated, with simultaneous activation of genes encoding cell surface receptors involved in pattern-triggered immunity and cytoplasmic NLRs (nucleotide-binding domain, leucine-rich repeat containing proteins) involved in effector-triggered immunity.

Cuticular waxes of nectarines during fruit development in relation to surface conductance and susceptibility to Monilinia laxa.

The cuticle is composed of cutin and cuticular waxes, and it is the first protective barrier to abiotic and biotic stresses in fruit. In this study, we analysed the composition of and changes in cuticular waxes during fruit development in nectarine (Prunus persica L. Batsch) cultivars, in parallel with their conductance and their susceptibility to Monilinia laxa.

Synthesis of new dicinnamoyl 4-deoxy quinic acid and methyl ester derivatives and evaluation of the toxicity against the pea aphid Acyrthosiphon pisum.

New dicinnamoyl (caffeoyl, feruloyl, ortho and para-coumaroyl) 4-deoxyquinic acid and esters were synthesized by using a new 4-deoxy quinic acid triol intermediate. The optimisation of both coupling and deprotection steps allowed the preparation in good yields of the target products either as the carboxylic acid or the methyl ester form. Eight new compounds were evaluated for their ability to influence the feeding behaviour of the pea aphid Acyrthosiphon pisum.

Isolation of C-glycosyl xanthones from Coffea pseudozanguebariae and their location.

The biochemical composition of leaves from Coffea pseudozanguebariae, a wild caffeine-free coffee species, was determined. Two phenolic compounds were extracted from leaves, separated and characterized. Their structures were elucidated by mass spectrometry, and 1D and 2D NMR spectroscopy and were shown to be mangiferin (1) and isomangiferin (2), which were the main polyphenol products.

Volatile organic compound emissions induced by the aphid Myzus persicae differ among resistant and susceptible peach cultivars and a wild relative.

Little is known on aphid-induced emissions of volatile organic compounds (VOCs) from trees and particularly on their intraspecific variability in association with resistance traits. We compared VOC emissions from five peach cultivars (Prunus persica (L.) Batsch) and a wild relative (Prunus davidiana (Carrière) Franch) that differ in their level (susceptible/resistant) and type (antixenosis, antibiosis) of resistance to the green peach aphid, Myzus persicae (Sulzer).

An integrative genomics approach for deciphering the complex interactions between ascorbate metabolism and fruit growth and composition in tomato.

Very few reports have studied the interactions between ascorbate and fruit metabolism. In order to get insights into the complex relationships between ascorbate biosynthesis/recycling and other metabolic pathways in the fruit, we undertook a fruit systems biology approach. To this end, we have produced tomato transgenic lines altered in ascorbate content and redox ratio by RNAi-targeting several key enzymes involved in ascorbate biosynthesis (2 enzymes) and recycling (2 enzymes).

How does tomato quality (sugar, acid, and nutritional quality) vary with ripening stage, temperature, and irradiance?

The objective of this study was to understand the respective impact of ripening stage, temperature, and irradiance on seasonal variations of tomato fruit quality. During ripening, concentrations in reducing sugars, carotenes, ascorbate, rutin, and caffeic acid derivates increased, whereas those in titratable acidity, chlorophylls, and chlorogenic acid content decreased. Fruit temperature and irradiance affected final fruit composition.