Management of soft rot in pakchoi (Brassica chinensis L.) using polyphenols from pineapple peel waste

Soft rot is one of the most susceptible soil-borne diseases of pakchoi (Brassica chinensis L.), severely hindering its industrial development. The research aimed to evaluate the application effect of polyphenols extracted from pineapple peel waste in improving the rhizosphere soil environment of pakchoi infected by soft rot and promoting plant health and growth. We found that using pineapple peel polyphenols (PPPs) at 4 mg/mL concentration (P1 treatment) significantly improved soil quality, reduced pakchoi disease incidence, and effectively promoted pakchoi growth. Compared with the control group (CK), the P1 treatment led to a marked 79.97 % reduction in diseased pakchoi leaves. Meanwhile, the rhizosphere soil structure showed reduced diseased genera and increased beneficial bacterial phyla, along with boosted soil enzyme activities. Furthermore, P1 treatment improved key growth parameters of pakchoi, including neck thickness (62.07 %), plant height (57.43 %), fresh weight (154.52 %), dry weight (121.88 %), maximum leaf length (47.28 %), width (30.98 %), and total chlorophyll content (50.11 %). The application of PPPs has shown significant effects in enhancing the ecological environment of the diseased soil and reducing the incidence of soft rot disease of pakchoi and has great potential in increasing the yield of pakchoi. This study offers an eco-friendly and sustainable approach for the valorization of PPPs and the management of soil-borne diseases, which holds profound implications for enhancing crop quality, soil health, and human well-being. [Display omitted] •Polyphenols from pineapple peel waste can effectively manage soil-borne diseases.•Pakchoi disease leaf rate decreased by 79.97 % under 4 mg/mL PPPs treatment.•Pakchoi exhibited significant growth and chlorophyll increases at 4 mg/mL PPPs.•PPPs decreased pathogenic genera and boosted beneficial ones in diseased soils.•Soil enzyme activities were enhanced by treatment with PPPs at 4–8 mg/mL.