Softening of Processed Plant Virus Infected Cucumis sativus L. Fruits

Anne-Katrin Kersten,Peer Martin,Peter Lentzsch,Martina Bandte,Sabrina Scharf,Peter Meurer,Carmen Büttner

doi:10.3390/agronomy11081451

Abstract

Texture softening of pickled cucumbers does not meet consumers’ quality expectations and leads to economic losses. The factor(s) triggering this phenomenon is still unknown. We investigated the importance of plant viruses such as Cucumber green mottle mosaic tobamovirus (CGMMV) and Zucchini yellow mosaic potyvirus (ZYMV) in the context of softening of pickles. Cucumber plants (Cucumis sativus) were infected by mechanical inoculation, grown under greenhouse conditions and tested positive for the viral infection by ELISA. The severity of virus infection was reflected in yield and symptom expression. Histological and morphological alterations were observed. All fruits were pasteurized, separately stored in jars and subjected to texture measurements after four, six and 12 months. CGMMV-infections were asymptomatic or caused mild symptoms on leaves and fruit, and texture quality was comparable to control. At the same time, fruits of ZYMV-infected plants showed severe symptoms like deformations and discoloration, as well as a reduction in firmness and crunchiness after pasteurization. In addition, histological alterations were detected in such fruits, possibly causing textural changes. We conclude that plant viruses could have a considerable influence on the firmness and crunchiness of pickled cucumbers after pasteurization. It is possible that the severity of symptom expression has an influence on texture properties.

Highlights

Cucumbers (Cucumis sativus L.) rank among one of the most widely cultivated cucurbits worldwide, with China representing the largest producer of cucumbers and gherkins [1,2]
Four cucumber plants per cultivar were artificially infected by mechanical inoculation of cotyledons with freeze-dried infected leaf material of Zucchini yellow mosaic potyvirus (ZYMV) (strain PV-0466, German Collection of Microorganisms and Cell Cultures (DSMZ), Braunschweig, Germany) or Cucumber green mottle mosaic tobamovirus (CGMMV) according to the supplier’s instructions
Knowledge about the influence of phytopathogenic viruses on fruit texture quality is missing, so the current hypothesis on viruses being an initiating or contributing factor of softening could neither be confirmed nor rejected. This was the first study to highlight the role of plant viruses in the context of softening pickles

Summary

Introduction

Cucumbers (Cucumis sativus L.) rank among one of the most widely cultivated cucurbits worldwide, with China representing the largest producer of cucumbers and gherkins [1,2]. Cucumbers are consumed fresh, cooked or preserved. The processing of these fruits targets preservation with minimal texture damage. Economic losses due to texture damage (softness) of stored pickles can only be overcome with improvements in their durability by identifying the cause of the softening [6]. Brands such as Spreewald gherkins (PGI) from Eastern Germany must maintain product quality to remain globally competitive

Methods

Results

Conclusion