<abstract xmlns="http://www.w3.org/1999/xhtml"><p>The ability of salicylic acid and jasmonic acid to suppress post-harvest infection with green mould <italic>Penicillium digitatum</italic> and blue mould <italic>P. italicum</italic> on three citrus species <italic>Citrus reticulata</italic> ‘Kinnow’, <italic>C. limon</italic> ‘Meyer Lemon’, and <italic>C. limetta</italic> ‘Mosambi’ was evaluated in a dose-response study. Salicylic acid (SA) and jasmonic acid (JA) were applied to the fruits as a post-harvest dip treatment followed by wound inoculation with the pathogens. Both resistance inducers caused a significantly lower disease severity compared with the infected but non-treated control, whereas disease incidence was not significantly lower than in the control. The efficacy of both SA and JA in reducing disease severity was concentration-dependent; the use of higher concentrations resulted in a greater degree of suppression. All the <italic>Citrus</italic> species tested in this study showed different responses in terms of disease development. <italic>C. limon</italic> ‘Meyer Lemon’ showed the highest disease development, and <italic>C. limetta</italic> ‘Mosambi’ the lowest. To get an insight into the mechanisms underlying the increase in resistance, the activity of defence-related enzymes – peroxidase (POD) and polyphenol oxidase (PPO) – was recorded in SA- and JA-treated fruit peelings. The activity of both enzymes was directly proportional to the concentration of the SA and JA applications. The highest activity of PPO and POD was observed in <italic>C. reticulata</italic> ‘Kinnow’ and the lowest in <italic>C. limon</italic> ‘Meyer Lemon’ fruits. This study is the first to document an increase in the activity of PPO and POD in SA- and JA-treated <italic>Citrus</italic> species in the presence of blue mould and green mould pathogens.</p></abstract>

The ability of salicylic acid and jasmonic acid to suppress post-harvest infection with green mould Penicillium digitatum and blue mould P. italicum on three citrus species Citrus reticulata ‘Kinnow’, C. limon ‘Meyer Lemon’, and C. limetta ‘Mosambi’ was evaluated in a dose-response study. Salicylic acid (SA) and jasmonic acid (JA) were applied to the fruits as a post-harvest dip treatment followed by wound inoculation with the pathogens. Both resistance inducers caused a significantly lower disease severity compared with the infected but non-treated control, whereas disease incidence was not significantly lower than in the control. The efficacy of both SA and JA in reducing disease severity was concentration-dependent; the use of higher concentrations resulted in a greater degree of suppression. All the Citrus species tested in this study showed different responses in terms of disease development. C. limon ‘Meyer Lemon’ showed the highest disease development, and C. limetta ‘Mosambi’ the lowest. To get an insight into the mechanisms underlying the increase in resistance, the activity of defence-related enzymes – peroxidase (POD) and polyphenol oxidase (PPO) – was recorded in SA- and JA-treated fruit peelings. The activity of both enzymes was directly proportional to the concentration of the SA and JA applications. The highest activity of PPO and POD was observed in C. reticulata ‘Kinnow’ and the lowest in C. limon ‘Meyer Lemon’ fruits. This study is the first to document an increase in the activity of PPO and POD in SA- and JA-treated Citrus species in the presence of blue mould and green mould pathogens.

Salicylic acid and jasmonic acid can suppress green and blue moulds of citrus fruit and induce the activity of polyphenol oxidase and peroxidase

Folia Horticulturae

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 License.

The ability of salicylic acid and jasmonic acid to suppress post-harvest infection with green mould Penicillium digitatum and blue mould P. italicum on three...

Salicylic acid and jasmonic acid can suppress green and blue moulds of citrus fruit and induce the activity of polyphenol oxidase and peroxidase

Published Online: Jun 30, 2019

Page range: 195 - 204

Received: Nov 08, 2018

Accepted: Feb 06, 2019

DOI: https://doi.org/10.2478/fhort-2019-0014

Keywords
enzymes, post-harvest, resistance inducers

© 2019 Anam Moosa et al., published by Sciendo

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 License.

Salicylic acid and jasmonic acid can suppress green and blue moulds of citrus fruit and induce the activity of polyphenol oxidase and peroxidase

Published Online: Jun 30, 2019

Page range: 195 - 204

Received: Nov 08, 2018

Accepted: Feb 06, 2019

DOI: https://doi.org/10.2478/fhort-2019-0014

Keywordsenzymes, post-harvest, resistance inducers

© 2019 Anam Moosa et al., published by Sciendo

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 License.

Keywords
enzymes, post-harvest, resistance inducers