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BIONÆR-Bionæringsprogram

Safe and secure food from field to fork: management of fungal hazards in horticultural crops via optical based strategies (HortiFood)

Alternative title: Trygg og sikker mat fra jord til bord: bekjempelse av soppsykdommer i hagebruksvekster ved bruk av optisk bestråling (HortiFood)

Awarded: NOK 5.0 mill.

Botrytis cinerea and Alternaria alternata are the two most important fungal pathogens that can cause severe pre- and post-harvest losses in strawberry and grape industry. Use of fungicides in management of these diseases are inevitable till today due to lack of viable, environmentally friendly alternatives. Photosensitizers could be either natural or synthetic compounds and its derivatives, which could be potentially used as sustainable eco-friendly approach to photodynamically inactivate the plant pathogens. A pool of potential photosensitizer candidates was screened ranging from natural compounds of plant sources to food grade additives and dyes. From these results, i) curcumin that absorbs blue light, ii) rose bengal dye that absorbs green light, and iii) new methylene blue, a phenothiazine dye, that absorbs red light have shown strong photosensitizing ability in suppressing the pathogen under in vitro conditions. Additional screening of these compounds was performed at plant level using simple detached leaf and fruit inoculation experiments to check the disease control efficiency and phytotoxicity on host system. Based on detached leaf assays, the concentration of photosensitizers (100µM) which had strong photosensitizing ability, caused photobleaching after 1 week of incubation. There was no significant reduction in disease progression observed in detached strawberry fruits incubated with photosensitizers and conidial suspensions, after 2 weeks. However, only a slight reduction at the initial rate of disease progression was observed when treated with curcumin. At this point, curcumin seems to be the best candidate followed by new methylene blue. Further experiments with detached leaves or intact plants are necessary to find proper balance between disease suppressive efficiency and phytotoxicity. To examine the role of storage temperature and ultraviolet (UV) treatment on melanization process in Botrytis cinerea, Petri dish level experiments were conducted with combinations of two different storage temperature (4 and 21 °C) and UV (no UV or 4 min 8 µmol m-2 s-1 UV daily) conditions. Petri dishes having potato dextrose agar and cellophane overlay were inoculated with conidial suspension. Samples were collected in different time points and total RNA was extracted. RNA Seq analysis will be done to examine the gene expression profile with more focus on melanization genes, photolyase gene, and cold adaptive genes.

Strawberry and grape are the two most important fruit crops grown worldwide for fresh and processed market. Botrytis cinerea and Alternaria alternata are the two most important fungal pathogens that can cause severe pre and post-harvest losses in this industry. At present, intensive use of fungicides and preservatives are inevitable in minimizing these losses. This endanger the UN sustainable development goal of ensuring food security by providing safe food. In this project, we will study the possible replacement of fungicides and preservatives by environmentally friendly optical radiation based strategies. While expanding the potential of optical radiation based strategies to another most important fungal pathogen Alternaria alternata, we will strengthen its practical application efficiency by exploring the i) possible role of melanin in UV screening and optical tolerance of Botrytis species, 2) storage temperature and its interaction with optical radiation in disease management efficiency, 3) selection and optimization of photosensitizer that can be exited with previously optimized optical wavelength range against powdery mildew management (250 nm-280 nm, 550 nm-660 nm), 4) effect of optical treatment on accumulation of secondary metabolites (anthocyanin, flavonols and toxins) and its potential impact on human health.

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BIONÆR-Bionæringsprogram