Natural abundance analysis of the role played by 15 N as indicator for the certification of organic-system deriving food

BACKGROUND

The natural abundance of stable isotope ¹⁵ N (δ¹⁵ N) in production systems has emerged as an alternative to distinguish organic products from conventional ones. This study evaluated the use of δ¹⁵ N values recorded for nitrogen fertilizers, soil and plant tissue in order to set the differences between organic and conventional agricultural production systems applied to rice, potatoes, apple and banana crops.

RESULTS

Values of δ¹⁵ N recorded for N sources ranged from +5.58‰ to +18.27‰ and from -3.55‰ to +3.19‰ in organic and synthetic fertilizers, respectively. Values recorded for δ¹⁵ N in food from organic rice, potatoes and banana farms were higher than values recorded for δ¹⁵ N in conventional farms; the same was observed for values recorded for δ¹⁵ N in leaves from the four crops.

CONCLUSION

Results have allowed for differentiation between production systems due to values of δ¹⁵ N recorded in leaves of all crops and food, for rice, potatoes and banana trees. © 2021 Society of Chemical Industry.

Hydroxybenzoate hydroxylase genes underlying protocatechuic acid production in Valsa mali are required for full pathogenicity in apple trees

Valsa mali is the causative agent of apple tree valsa canker, which causes significant losses in apple production. It produces various toxic compounds that kill plant cells, facilitating infection. Among these, protocatechuic acid exhibits the highest phytotoxic activity. However, those genes involved in toxin production have not been studied. In this study we identified four hydroxybenzoate hydroxylase genes (VmHbh1, VmHbh2, VmHbh3, and VmHbh4) from the transcriptome of V. mali. The VmHbh protein had high enzymatic activities of hydroxybenzoate hydroxylase, which could convert 4-hydroxybenzoate to protocatechuic acid. These four VmHbh genes all had highly elevated transcript levels during the V. mali infection process, especially VmHbh1 and VmHbh4, with 26.0- and 53.4-fold increases, respectively. Mutants of the four genes were generated to study whether VmHbhs are required for V. mali pathogenicity. Of the four genes, the VmHbh1 and VmHbh4 deletion mutants considerably attenuated V. mali virulence in apple leaves and in twigs, coupled with much reduced toxin levels. The VmHbh2 and VmHbh3 deletion mutants promoted the transcript levels of the other VmHbhs, suggesting functional redundancies of VmHbhs in V. mali virulence. The results provide insights into the functions of VmHbhs in the production of protocatechuic acid by V. mali during its infection of apple trees.

Current Distribution and Diagnostic Features of Two Potentially Invasive Asian Buprestid Species: Agrilus mali Matsumura and A. fleischeri Obenberger (Coleoptera: Buprestidae)

Simple Summary

Knowledge of the diagnostic features and native ranges of invasive pests is vital for their correct identification and monitoring. In this regard, the diagnostic characters and geographical ranges of two potentially invasive Asian buprestid species: the quarantine apple tree pest, Agrilus mali Matsumura, and the poplar pest A. fleischeri Obenberger are studied and analyzed. Based on the examination of museum collections and literature sources, the diagnostic characters to distinguish both species from their congeners are discussed, the comprehensive databases of records of the exact collecting sites are compiled, and detailed maps of their ranges are generated. Occurrence of A. mali in Japan is not confirmed. Outbreak sites of A. mali in Xinjiang most likely represent the newly forming invasion areas; their proximity to the wild apple stands in the Kazakh part of the Tien Shan is a direct threat to Kazakhstan and adjacent countries. Sites damaged by A. fleischeri in Liaoning are situated within its native range; the outbreaks were likely triggered by the switch from indigenous to introduced poplars. The results of the study will facilitate the correct identification and monitoring of the pests in case of their findings in new areas.

Abstract

Our goal is to analyze the known geographical ranges and diagnostic features of two potentially invasive Asian buprestid species: the quarantine apple tree pest, Agrilus mali Matsumura, and the poplar pest A. fleischeri Obenberger. Based on the examination of museum collections and literature sources, we compiled comprehensive databases of records of the exact collecting sites for both species and generated detailed maps of their ranges. There are 51 documented localities for A. mali in the Russian Far East and East Siberia, Mongolia, China, and the Korean peninsula, and there are 53 documented localities for A. fleischeri in the Far East and Siberia, Kazakhstan, Mongolia, China, and Japan. No evidence of the presence of A. mali in Japan was found. Outbreak sites of A. mali in Xinjiang in the 2000s most likely represent the newly forming invasion areas; their proximity to the wild apple stands in the Kazakh part of the Tien Shan is a direct threat to Kazakhstan and adjacent countries. Sites damaged by A. fleischeri in Liaoning are situated within its native range; the outbreaks were likely triggered by the switch from indigenous to introduced poplars. This situation is similar to the early stages of emerald ash borer (Agrilus planipennis Fairmaire) invasion.

Commodity risk assessment of Malus domestica plants from Serbia

The EFSA Panel on Plant health was requested to prepare and deliver risk assessments for commodities listed in the relevant Implementing Acts as 'High risk plants, plant products and other objects' (Commission Implementing Regulation (EU) 2018/2019 establishing a provisional list of high-risk plants, plant products or other objects, within the meaning of Article 42 of Regulation (EU) 2016/2031). The current scientific opinion covers all plant health risks posed by dormant bare rooted plants for planting of Malus domestica (1-2 years old) imported from Serbia, considering the available scientific information, including the technical information provided by the Plant Protection Directorate from Serbia on 27 December 2019. The relevance of an EU-quarantine pest for this opinion was based on evidence that: (a) the pest is present in Serbia; (b) the pest uses M. domestica as a host; (c) one or more life stages of the pest can be associated with the specified commodity. The relevance for this opinion of pests not regulated in the EU was based on the following criteria: (i) the pest is present in Serbia; (ii) the pest is not present in the EU; (iii) M. domestica is a host of the pest; (iv) the pest can be associated with the commodity and (v) the pest may have an impact and can pose potential risk for the EU territory. After the assessment of 1191 potential pests, one bacterium, Erwinia amylovora, fulfilled all criteria and accordingly, was selected for further evaluation. For this bacterium, the risk mitigation measures proposed in the technical dossier were evaluated. Limiting factors on the effectiveness of the measures were also considered. For the selected species, an expert judgement is given on the likelihood of pest freedom taking into consideration the risk mitigation measures acting on E. amylovora, including any uncertainties. Based on the outcomes of an Expert Knowledge Elicitation, the Panel is considering a pallet as a unit; and taking into account the uncertainties associated with the assessment, the panel is 95% sure that 9,934 or more pallets out of 10,000 will be pest free.