Effects of cis-Jasmone Treatment of Brassicas on Interactions With Myzus persicae Aphids and Their Parasitoid Diaeretiella rapae

There is a need to develop new ways of protecting plants against aphid attack. Here, we investigated the effect of a plant defence activator, cis-jasmone (CJ), in a range of cultivars of Brassica napus, Brassica rapa and Brassica oleracea. Plants were sprayed with cis-jasmone or blank formulation and then tested with peach potato aphids (Myzus persicae Sulzer) (Hemiptera: Aphididae) and their parasitoid Diaeretiella rapae (M'Intosh) (Hymenoptera: Braconidae). CJ treated plants had significantly lower aphid settlement than control plants in a settlement bioassay. Conversely, in a foraging bioassay, D. rapae parasitoids spent a significantly longer time foraging on CJ treated plants. Our results reveal that CJ treatment makes plants less attractive to and less suitable for M. persicae but more attractive to D. rapae in a range of brassica cultivars. It is likely that these effects are due to changes in volatile emission indicating activation of defence and presence of conspecific competitors to aphids but presence of prey to parasitoids. Increases in volatile emission were found in CJ induced plants but varied with genotype. Among the synthetic volatile compounds that were induced in the headspace of CJ treated brassica cultivars, methyl isothiocyanate, methyl salicylate and cis-jasmone were most repellent to aphids. These results build on earlier studies in Arabidopsis and show that tritrophic interactions are influenced by CJ in a wide range of brassica germplasm. The implication is that CJ is a promising treatment that could be used in brassica crops as part of an integrated pest management system.

Evaluating The Impact of Strigolactone GR24 On Capparis Spinosa L. Callus Production And Phenolic Compound Content

The effect of strigolactones on plants, which has been recently described as a new group of plant hormones, has not been fully characterized. Capparis spinosa L. callus formation using synthetic strigolactone GR24 (0.1 and 0.2 μM) alone or in combination with 1-naphthalene acetic acid (NAA) (2 mg / L) and 6-benzylaminopurine (BAP) (1 mg / L) and its effect on phenolic substance production were evaluated. 2 mg/L NAA+1 mg/L BAP+0.1 μM GR24 was the medium with the highest callus formation (60.3%) and callus fresh weight (120.8 mg). In the phytochemical analysis, the highest total flavonoid and phenolic substance and the highest rutin, quercetin, chlorogenic acid content were found in this application and their amounts increased at various rates compared to the control. Aromatic substances in caper calluses were grouped as sulfur compounds (66.97% -87.53%), aldehydes (4.88% -7.90%), ketones (0.34% -19.3%), hydrocarbons and derivatives (0.56%-5.8%), alcohols (% 1.62-6.08%), others (0.61% -2.37%) and their amounts varied at various hormone applications. When 0.1 μM GR24 was applied alone, the total sulfur compound in callus samples was 87.53% and the dominant substance was found to be methyl isothiocyanate.

Volatile Profile in Different Aerial Parts of Two Caper Cultivars (Capparis spinosa L.)

This research presents, for the first time, full volatile profiles of four aerial parts of caper plants (Capparis spinosa L.) from southeastern Spain. Volatile compounds in caper leaves and stems (together), flowers, flower buds, and fruits from two cultivars were identified and quantified using headspace-solid phase microextraction (HS-SPME) and gas chromatography with a mass spectrometry detector (GC-MS). Forty-three volatile compounds were identified in the caper shoots, 32 in caper flowers, with only 18, 10, and 6 compounds being found in flower buds, leaves, and fruits, respectively. The predominant compound in all studied materials was methyl isothiocyanate, with nerolidol, trans-2-hexenal, and nonanal playing key roles in flowers, leaves, and flowers buds, respectively. The two studied cultivars had the same volatile compounds but at very different concentrations, although the two studied cultivars are cultivated under the same climatic and agronomic conditions. Additionally, the predominant compounds, especially methyl isothiocyanate (6882 mg·kg−1 fw in flower buds of ORI 3 cultivar), can be separated and concentrated for future applications in food technology.