“Medicinal plant extracts enhanced the shelf life of chilli fruits against the anthracnose disease through defense modulation”

Abstract

Colletotrichum capsici is a severe concern for the post-harvest management of chilli fruit. Mostly synthetic fungicide is used to protect chilli fruits after harvesting, which contain many toxic compounds, and it's become the most significant issue for the consumers' health. In the current study, antifungal activity of leaf and stem extracts of different medicinally important plants such as Acalypha indica, Adhatoda vasica, Alternanthera sessilis, and Peristrophe paniculata were examined against the C. capsici on chilli fruits. The chilli fruits were treated with plant extracts ‘before’ and ‘after’ the inoculation of the fungal pathogen at two different temperatures (25 °C and 4 °C). The plant extract treatment ‘before pathogen inoculation’ was more effective than ‘after pathogen inoculation in controlling the anthracnose disease of chilli fruits. Results revealed that most plant extracts showed better disease resistance (small size of lesions, low weight loss, higher pH, and increased titrable acidity) at 4 °C than 25 °C. The maximum disease incidence (33.88%) resulted in leaf extract of A. sessilis ‘before pathogen inoculation’, and it minimized the lesion size up to 15 mm. Similarity reduced the decay by 53% at 25 °C, and a similar manner of disease reduction was followed by A. vasica, P. paniculata, and A. indica. Further, PPO, POD, CAT, SOD, and PAL enzyme quantification showed leaf extract of A. sessilis ‘before pathogen inoculation’ significantly induced the plant defense against the C. capsici. In conclusion, A. sessilis leaf extract treatment ‘before pathogen inoculation’ was found most efficient in reducing anthracnose disease in chilli fruits. The bioactive compounds of the leaf extract of A. sessilis could function in C. capsici growth inhibition and defense activation of chilli fruits.