Pre-Harvest Treatment of Chitosan Oligosaccharides Improved Strawberry Fruit Quality

Abstract

Chitosan oligosaccharide (COS), derived through hydrolysis of chitosan, has been proved to be an effective plant immunity elicitor, eco-friendly, and easily soluble in water, and influenced several secondary metabolites content to improve fruit qualities. COS are widely used in agriculture to improve the defense response in plants. The purpose of this study was to investigate the pre-harvest treatment effect of COS on the quality of strawberry (Fragaria × ananassa cv. qingxiang). COS was dissolved in distilled water at a concentration of 50 mg·L−1 and sprayed at four different growth stages of strawberry plants, namely seedling stage, before flowering, fruit coloring (the stage of fruit from white to red) and full bloom. Uniform size, shape, color, without any visible damage, and disease-free fruits were harvested for determining the quality. The results showed that the fruit firmness, viscosity, lignin, sugars, protein, total soluble solid, and titratable acidity content increased in COS-treated fruits compared to control. In addition, COS pre-harvest treatment had a positive effect on anthocyanin, total phenol, flavonoid, vitamin C content and DPPH(2,2-diphenyl-1-picrylhydrazyl) scavenging activity of strawberry. Moreover, COS also increased the cell wall composition and regulated gene expression of some important enzymes involved in ethylene compound biosynthesis and cell wall degradation. The finding of this study suggests that pre-harvest application of COS is very useful for improving quality and antioxidant capacity of strawberry.

Investigation of the cause of reduced sugar content in Kiyomi tangor fruit of Ziyang xiangcheng (Citrus junos Sieb. ex Tanaka) rootstock

“…TS content in ripe fruit was estimated using the anthrone–sulphuric acid method with minor modifications 56 , while TA content was determined using the He’s 57 method with slightly modification.…”

Postharvest application of pectic‐oligosaccharides on quality attributes, activities of defense‐related enzymes, and anthocyanin accumulation in strawberry

“…He et al . (2018) reported that preharvest spraying of chitosan oligosaccharides is useful for preserving the firmness of strawberries. Treatment with alginate oligosaccharides also had a positive effect on strawberry fruit firmness by inhibiting the expression of genes related to cell‐wall degrading enzymes, and delaying the degradation of cell walls …”

“…46,47 The cell wall disassembly process involves the depolymerization of the xyloglucan-cellulose matrix, and the solubilization of pectins, which contribute to fruit softening. 48 He et al (2018) 49 reported that preharvest spraying of chitosan oligosaccharides is useful for preserving the firmness of strawberries. Treatment with alginate oligosaccharides also had a positive effect on strawberry fruit firmness by inhibiting the expression of genes related to cell-wall degrading enzymes, and delaying the degradation of cell walls.…”

RNA-seq and metabolome revealed counter effect of chitosan against Botrytis cinerea on grape berries

“…Chitosan application enhanced growth and also triggered the accumulation of phenolic secondary metabolites in fruits [58]. Y He, S Bose, W Wang, X Jia, H Lu and H Yin [59] also suggested that the chitosan application will not only trigger plant immunity, but also influences the accumulation of several secondary metabolites. Furthermore, chitosan also improved the cell wall structure and controlled gene expression of specific significant enzymes convoluted in cell wall degradation and ethylene compound biosynthesis.…”