Hoe kan nieuwe GLB bijdragen aan klimaat, natuur en landschap?

Eind 2021 diende het Ministerie van Landbouw, Natuuren Voedselkwaliteit (LNV) in Brussel een concept in vanhet Nationaal Strategisch Plan (NSP). Iedere lidstaat moestzo’n plan bij de Europese Commissie inleveren. Dit novumis het gevolg van de ingrijpende aanpassingen die hetGemeenschappelijk Landbouwbeleid (GLB) ondergaat.Het vroegere Plattelandsontwikkelingsprogramma (POP)vervalt. Binnenkort onderhandelt LNV met de EuropeseCommissie over het ingediende plan. Wat gaat dit betekenenvoor natuur en landschap

Diagnosis and detection of host-specific forms of Fusarium oxysporum

Diagnosis and detection of host-specific forms of Fusarium oxysporum are traditionally based on the combination of diagnostic symptoms on the host with the presence of the fungus in the affected tissues. The classical approach is becoming increasingly problematic because more than one forma specialis may occur on a given host, along with non-pathogenic strains which are common soil and rhizosphere inhabitants. Neither formae speciales nor pathogenic races within formae speciales can be distinguished morphologically. Although united by joint pathogenicity to a given host, strains belonging to the same forma specialis need not be phylogenetically related. Development of diagnostics for host-specific groups in F. oxysporum requires monophyletic target groups. Recent studies on gene-genealogy and AFLP-based phylogenies show that the majority of formae speciales in F. oxysporum are polyphyletic (unnatural) and do not offer any prospects for the development of molecular diagnostics. In contrast, highly specific PCR primers have been developed for formae speciales (or races) that consist of a single clonal lineage, and for monophyletic groups of lineages within a forma specialis. Among others, specific PCR primers have thus been developed for F. oxysporum f. sp. basilici, specific races in F. oxysporum ff. spp. dianthi and gladioli, and for the EPPO A2 (EU II/A1) quarantine fungus F. oxysporum f. sp. albedinis which can reliably replace conventional isolation and pathogenicity testing procedures

Regeneration of vascular tissues in relation to Fusarium wilt resistance of carnation

Fusarium wilt-resistant 'Novada' carnations responded both to stem inoculation with a conidial suspension of Fusarium oxysporum f. sp. dianthi or F. oxysporum f. sp. lycopersici and to root inoculation by planting in soil infected with F. oxysporum f.sp. dianthi by means of a localization mechanism comprising gel formation in the xylem vessels and hyperplasia of adjacent parenchyma cells. Dye translocation experiments showed that xylem transport was limited by the presence of vascular gels, although wilting did not occur. Overcapacity of the vascular system apparently allowed for sufficient water transport to compensate for local vascular dysfunction. Also, vascular regeneration in the hyperplastic tissue next to occluded xylem vessels created new pathways for water transport to compensate for those lost by occlusion. Regeneration of xylem vessels was eventually followed by regeneration of xylem fibers, xylem parenchyma, cambium, and phloem cells. 'Early Sam' carnations, susceptible to Fusarium wilt, responded to stem inoculation with F. oxysporum f. sp. lycopersici by similar localization of infection and vascular regeneration. Stem inoculation with F. oxysporum f. sp. dianthi, however, resulted in colonization of the xylem vessels followed by lysis of the vascular tissues. Vascular gelation, hyperplasia of parenchyma cells, and vascular regeneration did generally not occur. However, if some hyperplasia occurred in attempted defence, some differentiation of hyperplastic cells into single xylem vessel elements was observed which only rarely resulted in complete vascular regeneration next to colonized xylem. In the absence of hyperplasia, differentiation of medulla parenchyma cells bordering destroyed vascular tissue into xylem vessel elements was even more exceptional. Apparently, vascular regeneration in carnation is a normal defence reaction to fungal invasion