Induced resistance in postharvest fruits and vegetables by chemicals and its mechanism

 

 

Yang Bi *, Yongcai Li and Yonghong Ge

College of Food Science and Engineering, Gansu Agricultural University, Lanzhou, China

 

Abstract

Purpose of review: This review describes research indicating that chemical-induced resistance can be part of postharvest disease control and provides brief knowledge of the mechanism of inducing resistance in fruits and vegetables.

Findings: Fruits and vegetables can be induced to develop enhanced resistance to pathogen infection by pre- or postharvest treatment with a variety of chemical elicitors including salicylic acid, acibenzolar, harpin, jasmonic acid, silicon and chitosan. Resistance induced by these chemicals is broad spectrum and long lasting, but rarely provides complete control of infection. The mechanism of induced resistance is involved in: the accumulation of pathogenesis-related proteins, defence enzymes and antifungal compounds; increasing of activated oxygen; and lignification of epidermal cells.

Limitations: In most cases, treatments need to be applied prior to infection occurring so that the crop has time to induce its defences before the pathogens infect. Induced resistance may not be effective against all pathogens and the protection is rarely complete. Environmental conditions may influence the crop to stimulate its defence mechanism so that the resistance can be variable.

Directions for future research: Having more precise information on induced resistance in fruits and vegetables will be of use in determining which crops may be suitable for this type of control. A better understanding of induced resistance response in more than one crop is important for developing any generalisations about this type of resistance. There is also a need to evaluate quality changes in induced tissues and be assured that induced natural defence compounds that are effective against pathogens are not present in consumed tissues at levels toxic to mammals. In order to maximise the efficacy of resistance elicitors, a greater understanding is required of the effect of genotype, maturity, postharvest handling and environmental condition, and any interactions between these.

 

Key words: decay; induced resistance; elicitors; mechanism

 

Stewart Postharvest Review 2007, 6:1

Published online 01 December 2007

doi: 10.2212/spr.2007.6.1