No abstract

Pathogen infection can induce plant volatile organic compounds (VOCs). We infected ‘McNeal’ wheat and ‘Harrington’ barley with a Fusarium spp. blend (F. graminearum,F. avenaceum and F. culmorum). Both cereals had the greatest VOC induction 14 days after pathogen innoculation, only slightly lower induction occurred at 7 days, but displayed no induction at 1 days. The induced VOC bouquet for both cereals included six green leaf volatiles (GLVs; e.g. (Z)‐3‐hexenol and (Z)‐3‐hexenyl acetate), four terpenes (linalool, linalool oxide, (Z)‐β‐ocimene and (E)‐β‐caryophyllene) and benzyl acetate. Neighbouring, uninfected individuals of both cereals had significant VOC induction when exposed to an infected, conspecific plant. The temporal pattern and VOC blend were qualitatively similar to infected plants but with quantitative reductions for all induced VOCs. The degree of neighbouring, uninfected plant induction was negatively related to distance from an infected plant. Plant VOC induction in response to pathogen infection potentially influences herbivore attraction or repellency. Y‐tube tests showed that herbivorous female and male Oulema cyanella Voet. (Chrysomelidae: Coleoptera) were significantly attracted to (Z)‐3‐hexenal and (Z)‐3‐hexenyl acetate at 300 and 1500 ng/h but were repelled by both GLVs as well as (Z)‐β‐ocimene and linalool at 7500 ng/h. These O. cyanella behavioural responses were significantly at higher concentrations than those emitted by single plants with pathogen‐induced VOCs, so adults might only be able to respond to a dense group of infected plants. Also, O. cyanella dose responses differ from the previously tested congeneric O. melanopus (cereal leaf beetle), which was attracted to three VOCs induced by Fusarium infection of maize, barley and wheat. Future behavioural tests may indicate whether different herbivore dose responses measured with each VOC singly can help to predict attraction or repellency to injured and uninjured VOC bouquets from different host plant species.

Sustainable agriculture with low inputs of chemicals and fertilizers has been recently attracting more attention from producers and researchers in the EU. The main reason for such attention is The European Green Deal—the EU’s latest growth strategy concerning environmental degradation and climate change. One of its main components is the Farm to Fork strategy, which especially features the reduction in pesticide and mineral fertilizer application and also supports the development of organic farming. At the same time, food demand is rising. These ambitious challenges require extensive research, development and innovation. Therefore, new non-chemical techniques for improving plant growth and resistance to biotic and abiotic stresses must be explored for their potential in this field. One of the most promising is the use of non-thermal plasma for such purposes. As this physical factor is a complex mixture of ions, atoms, electrons, radicals and molecules, its effect on plants and pathogens is also complex. This review presents different aspects of the effect of non-thermal plasma on seed germination, development of seedlings, plants and pathogens. The literature was explored to provide evidence for the possible use of non-thermal plasma for boosting plant growth and plant protection.

Differently substituted hetaryl thioketones react with less reactive diazoketones under MW irradiation in toluene solution. After only 2 min, the reactions were complete and, depending on the type of the used diazoketone, ,-unsaturated ketones, acyl substituted thiiranes or 1,3-oxathiols were obtained as final products. In the case of azibenzil and di(thiophen-2-yl) thioketone, a new type of 1,5dipolar electrocyclization of the intermediate thiocarbonyl ylide involving a thiophene ring led to a fused sulfur heterocycle. In contrast to hetaryl thioketones, the ferrocenyl analogues decompose under MW irradiation. Alternatively they react with diazopropanone and 2-diazo-1-phenylethanone in boiling THF in the presence of LiClO4 to give ,-unsaturated ketones as sole products. In these cases, the reactions require long reaction times.