The effect of carbamic acid, (1,2,3-thiadiazole-4-ylcarbonyl)-hexyl ester on Peronophythora litchii infection, quality and physiology of postharvest litchi fruits

Hai Liu,Fuying Luo,Zaifeng Li,Yueming Jiang,Guoxing Jing

doi:10.1186/s13065-017-0244-x

Abstract

BackgroundLitchi (Litchi chinensis Sonn.) is a subtropical fruit with attractive characteristic of white to creamy semitranslucent flesh and red color in pericap, but it was easily subjected to the infection of Peronophythora litchii and lost its market values. Experiments were conducted to understand the effect of [Carbamic acid, (1,2,3-thiadiazole-4-ylcarbonyl)-hexyl ester, CTE] on the growth of P. litchi and quality properties in litchi fruits during postharvest storage.ResultsIn vitro experiments, CTE with minimum inhibitory concentration (MIC, 5 mg/L) and minimum fungicidal concentration (MFC, 10 mg/L) were against the growth of P. litchi for 2 and 4 days, respectively, and SEM results showed that hyphae of P. litchii shrank, distorted and collapsed after CTE treatment. In vivo experiments, CTE treatment inhibited the increase of disease incidence, browning index, weight loss and PPO activity in non-P. litchii-inoculated fruits, meanwhile the treatment markedly inhibited the decrease of color characteristic (a*, b* and L*), anthocyanin content, phenolic contents, Vc content and POD activity, but TSS content was not significantly influenced during storage. In P. litchii-inoculated fruits, all these above mentioned parameters in CTE treated fruits were significantly higher than that in control fruits, but anthocyanin content, Vc, TSS and TA content did not have consistent differences between control and CTE treated fruits at the end of storage.ConclusionCTE treatment reduced the disease incidence and browning index of litchi fruits, maintained the fruits quality and, thus, it could be an effective postharvest handling to extend the shelf life of litchi fruits during storage.

Highlights

Litchi (Litchi chinensis Sonn.) is a subtropical fruit with attractive characteristic of white to creamy semitranslucent flesh and red color in pericap, but it was subjected to the infection of Peronophythora litchii and lost its market values
The carboxyl acid amide (CAA) fungicides were extensively used for against different downy mildews, the antifungal mechanism was that multisite inhibitors in CAA could react with the thiol groups presented in the enzymes of fungi, but the CAAresistant isolates of Plasmopara viticola and Pseudoperonospora cubensis have been detected in some European regions, South Korea, Israel, the United States and China after long usage [23]
The results demonstrated that oxidative stress species such as H2O2 was removed by the higher POD activity, so the CTE treatment prolonged the storage of litchi fruits

Summary

Introduction

Litchi (Litchi chinensis Sonn.) is a subtropical fruit with attractive characteristic of white to creamy semitranslucent flesh and red color in pericap, but it was subjected to the infection of Peronophythora litchii and lost its market values. Litchi (Litchi chinensis Sonn.) is a subtropical fruit with high commercial value in southern China, it owns the attractive characteristic of white to creamy semitranslucent flesh and red color in pericap [1, 2]. Carbamic acid, (1,2,3-thiadiazole-4-ylcarbonyl)-hexyl ester (CTE), which containing thiadiazole, a carbamate group and a heterocyclic ring, showed a strong fungistatic activity against Alternaria kikuchiana and Gibberella zeae [13], but the antifungal activities of CTE on the control of litchi postharvest disease was remain undetermined. Based on the potential broad antifungal spectrum of CTE on the diseases [11,12,13], the objective of this study was conducted to investigate the effect of CTE on the inhibition of P. litchii through in vitro and the influence on fruits quality in vivo experiments

Objectives

Methods

Results

Discussion

Conclusion