Following a request from the European Commission, EFSA was asked to create and regularly update a database of host plant species of Xylella spp. The mandate now covers the period 2021-2026 and EFSA is requested to release an update of the database twice per year. The aim of the database is to provide information and scientific support to risk assessors, risk managers and researchers dealing with Xylella spp. This report is related to the fifth version of the database published in Zenodo in the EFSA Knowledge Junction community, covering literature published from 1 January 2021 up to 30 June 2021, and recent Europhyt outbreak notifications. Informative data have been extracted from 41 selected publications. Nineteen new host plants were identified and added to the database since the previous update published in June 2021. Those plant species were reported naturally infected by subsp. multiplex or unknown (i.e. not reported in the publication) of X. fastidiosa in the UE (France, Spain and Portugal). No additional data were retrieved for X. taiwanensis . New information on the tolerant/resistant response of plant species to X. fastidiosa infection were added, while no new STs have been identified worldwide compared to the previous update published in May 2021. The overall number of Xylella spp. host plants determined with at least two different detection methods or positive with one method (between: sequencing, pure culture isolation) now reaches 407 plant species, 185 genera and 68 families. Such numbers raise to 655 plant species, 293 genera and 88 families if considered regardless of the detection method applied.

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Following a request from the European Commission, EFSA was asked to create and regularly update a database of host plant species of Xylella spp. In 2018, EFSA released a new Xylella spp. host plant database that was now updated with informative data extracted from 76 recent publications retrieved through an extensive literature search. This report is related to the third version of the database published in Zenodo in the EFSA Knowledge Junction community, covering articles selected from: a systematic literature review conducted up of 30 June 2019; Europhyt database up to 15 October 2019; and relevant articles identified by EFSA Horizon scanning and personal communications from experts. Some data on Xylella fastidiosa strains and geographical coordinates included in the already published database were updated or modified with the purpose of increasing the accuracy and consistency of the database itself. Thirty-seven new host plant species of X. fastidiosa, identified through the data extracted from the selected publications, have been added to the database. Those plant species were reported as naturally infected, artificially infected or infected under unspecified conditions by subsp. multiplex , pauca or unknown (i.e. not reported in the publication) subspecies of X. fastidiosa . No additional data were retrieved for Xylella taiwanensis . Six new Sequence Types (STs) have been identified in Brazil, Italy and the USA. Information on the tolerant/resistant response of plant species or varieties to X. fastidiosa infection are also reported in the database. The overall number of Xylella spp. host plants reaches now 343 plant species, 163 genera and 64 families determined with two different detection methods, till 595 plant species, 275 genera and 85 families regardless the detection method applied. The EFSA database on Xylella spp. host plants is updated regularly with the aim to provide information and scientific support to risk assessors, risk managers and researchers dealing with Xylella spp.

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Abiotic and biotic stresses limit the growth and productivity of plants. In the current global scenario, in order to meet the requirements of the ever-increasing world population, chemical pesticides and synthetic fertilizers are used to boost agricultural production. These harmful chemicals pose a serious threat to the health of humans, animals, plants, and the entire biosphere. To minimize the agricultural chemical footprint, extracts of Ascophyllum nodosum (ANE) have been explored for their ability to improve plant growth and agricultural productivity. The scientific literature reviewed in this article attempts to explain how certain bioactive compounds present in extracts aid to improve plant tolerances to abiotic and/or biotic stresses, plant growth promotion, and their effects on root/microbe interactions. These reports have highlighted the use of various seaweed extracts in improving nutrient use efficiency in treated plants. These studies include investigations of physiological, biochemical, and molecular mechanisms as evidenced using model plants. However, the various modes of action of A. nodosum extracts have not been previously reviewed. The information presented in this review depicts the multiple, beneficial effects of A. nodosum -based biostimulant extracts on plant growth and their defense responses and suggests new opportunities for further applications for marked benefits in production and quality in the agriculture and horticultural sectors.

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The negative effects of the ongoing climate change include unusual prolonged droughts and increased salinity pressures on the agricultural lands. Consequently, crops are facing unprecedented environmental pressure, and this calls for more research toward controlling such major stresses. The current study investigates the effects of seaweed extract sprays of Ascophyllum nodosum (5 and 7 mL·L -1 ; 6 day intervals) on Paspalum vaginatum Salam' during prolonged irrigation intervals (2 and 6 day) and saline growing conditions (1 and 49.7 dS·m -1 ) for 6 weeks in containers under greenhouse conditions. Control plants showed reduced turf quality, photochemical efficiency, root length and dry weight, total non-structural carbohydrates, and K and Ca compositions. Seaweed extracts increased turf quality, leaf photochemical efficiency, root length and dry weight, total non-structural carbohydrates, K, Ca, and proline in treated plants during prolonged irrigation intervals as well as saline shock conditions. There were also increases in the antioxidant defensive mechanisms such as catalase (CAT), superoxide dismutase (SOD) and ascorbate peroxidase (APX) activities and non-enzymatic antioxidants as well as reduced lipid peroxidation. The application of SWE at 7 mL·L -1 showed higher performance in treated plants during prolonged irrigation intervals as well as saline conditions. Our findings imply that several mechanisms including drought tolerance, osmotic adjustment and antioxidant defense system may interact to enhance the performance of plants in the face of environmental stress following SWE treatments.

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Seaweed extracts (SWE) might play an important role in enhancing growth and phytochemical composition of medicinal shrubs. In this study, we investigate the morphological, physiological and biochemical effects of irrigation levels (100% and 50% of the evapotranspiration rate) coupled with a weekly treatment of SWE of Ascophyllum nodosum at 5 and 7 mL L(-1) as a soil drench or foliar spray on Spiraea nipponica "Snowmound" and Pittosporum eugenioides "Variegatum" grown in containers under controlled greenhouse conditions. In addition, the phenolic and flavonoid content, antioxidant capacity and lipid peroxidation in both plant species was largely enhanced while the proline accumulation was reduced. After 8 weeks of treatments, drought condition reduced plant vegetative growth and gas exchange, as well as leaf water potential, but increased the phenolic and flavonoid contents in leaves, their antioxidant capacities and proline content. The application of SWE enhanced the performance of both species during mild drought conditions by means of increasing leaf number and area, dry weights, plant height, gas exchange and leaf water potential. The maximum vegetative growth, physiological performance and phytochemical composition of both species was achieved using the drench SWE treatments (5 and 7 mL L(-1)) in moderate drought conditions, which improved the plant water status, stomatal conductance, and photosynthetic rate. SWE enhanced plant growth and the phytochemical composition and antioxidant capacity of plant leaves of both species during moderate drought conditions.

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