Exogenously Applied Chitosan and Chitosan Nanoparticles Improved Apple Fruit Resistance to Blue Mold, Upregulated Defense-Related Genes Expression, and Maintained Fruit Quality

Fayz A. Abdel-Rahman,Hoda A. S. El-Garhy,Gehan A. Monir,Mohamed H. Refaat,Yosra Ahmed,Ismail A. Ismail,Mabrouk S. S. Hassan

doi:10.3390/horticulturae7080224

Fayz A. Abdel-Rahman, Hoda A. S. El-Garhy + Show 5 more

Open Access

https://doi.org/10.3390/horticulturae7080224

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Abstract

Blue rot disease caused by Penicillium expansum is one of the most widespread fungal diseases that affects apples worldwide. This work was to verify the effect of chitosan (2 and 4 g/L) and its nano-form (0.2 and 0.4 g/L) against blue rot disease on apples and their effect on the expression of six defense-related genes as well as fruit quality parameters. Regarding disease incidence, in most cases, chitosan NPs performed better as compared to their raw materials for both artificial and natural infections. The highest efficacy was obtained for chitosan NPs at 0.4 g/L for artificial and natural infection in both 2019 and 2020 seasons. All treatments kept fruit quality parameters regarding firmness, total soluble solids, and titratable acidity for artificial and natural infection in both seasons. As expected, the exogenous application of chitosan NPs and bulk form triggered an increase in the expression levels of six defense-related genes including chitinase, peroxidase, β-1,3-glucanase, Xyloglucan endotransglycosylase (XET), pathogenesis-related protein (PR8), and phenylalanine ammonia lyase-1 (PAL1). Moreover, the highest mRNA quantity of all the studied genes was detected in leaves treated with chitosan NPs at both concentrations compared to other treatments. Chitosan NPs can be considered an eco-friendly and effective approach against blue mold of apples and can be integrated into management programs to maintain postharvest quality and extend the shelf life of fruits.

Highlights

Introduction iationsDuring 2018, Egypt produced around 704,727 tons of apples and the harvested area was almost 28,085 ha, with a yield of 250,926 hg/ha [1]
All tested treatments reduced P. expansum growth on potato dextrose agar (PDA) medium compared with control Table 2
The mycelial growth of P. expansum was more sensitive to high concentrations of nano-chitosan compared with other treatments

Summary

Introduction

During 2018, Egypt produced around 704,727 tons of apples and the harvested area was almost 28,085 ha, with a yield of 250,926 hg/ha [1]. Apples are exposed during handling, transportation, and storage to many economically influencing fungal diseases, the most important of which are fruit rot, especially those caused by Penicillium fungi. Research conducted in this field has shown that blue rot disease caused by Penicillium expansum (Link) thorn is one of the most widespread fungal diseases that affects apples in all countries of the world after they are collected during handling or in storage.

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