Articles
Suppressive on-farm compost inducing priming against wild rocket wilting
Article number
1442_26
Pages
199 – 206
Language
English
Abstract
Effective preharvest crop management against pathogens is reflected in yield and quality.
Wild rocket (Diplotaxis tenuifolia L. [DC.]) is susceptible to soil sickness-related soilborne pathogens, such as Fusarium oxysporum f. sp. raphani, causal agent of wilting.
The induction of systemic plant defence responses (ISR) as potential suppressiveness mechanism mediated by compost application can be a promising strategy to slow down outbreaks.
In this work, a compost obtained from the on-farm composting of olive prunings, salad vegetables and tomato residues in a ratio of 51.7:15.0:33.3 (dry weight), highly suppressive against wild rocket wilt, was explored alone and in combination with Trichoderma harzianum strain TH23, for priming plant defenses.
Wild rocket seedlings were grown for two weeks on three comparing treatments: control sterilized peat, peat amended with 20% (v/v) compost, and combination of peat amended with 20% (v/v) compost and drenched with TH23 spore suspension (106 conidia mL‑1). Then, plants were inoculated by root dipping in a F. oxysporum f. sp. raphani water suspension (106 conidia mL‑1) for 20 min and transplanted on the same treatments.
Non-inoculated plants were used as controls.
A subset of plants was sampled 24 h after infection for RNA extraction and qPCR analysis; the remaining ones were followed for 15 days for disease monitoring.
Findings indicated that compost reduced disease severity by around 45% and vegetative decay.
Infected plants grown in compost- and compost/TH23-enriched peat showed an overexpression of lipoxygenase gene 2 (LOX2) and pathogenesis related protein 1 (PR1), indicating the activation of plant defence responses mediated by jasmonic and salicylic acid pathways.
The overexpression of both genes suggested a putative early activation of ISR.
Wild rocket (Diplotaxis tenuifolia L. [DC.]) is susceptible to soil sickness-related soilborne pathogens, such as Fusarium oxysporum f. sp. raphani, causal agent of wilting.
The induction of systemic plant defence responses (ISR) as potential suppressiveness mechanism mediated by compost application can be a promising strategy to slow down outbreaks.
In this work, a compost obtained from the on-farm composting of olive prunings, salad vegetables and tomato residues in a ratio of 51.7:15.0:33.3 (dry weight), highly suppressive against wild rocket wilt, was explored alone and in combination with Trichoderma harzianum strain TH23, for priming plant defenses.
Wild rocket seedlings were grown for two weeks on three comparing treatments: control sterilized peat, peat amended with 20% (v/v) compost, and combination of peat amended with 20% (v/v) compost and drenched with TH23 spore suspension (106 conidia mL‑1). Then, plants were inoculated by root dipping in a F. oxysporum f. sp. raphani water suspension (106 conidia mL‑1) for 20 min and transplanted on the same treatments.
Non-inoculated plants were used as controls.
A subset of plants was sampled 24 h after infection for RNA extraction and qPCR analysis; the remaining ones were followed for 15 days for disease monitoring.
Findings indicated that compost reduced disease severity by around 45% and vegetative decay.
Infected plants grown in compost- and compost/TH23-enriched peat showed an overexpression of lipoxygenase gene 2 (LOX2) and pathogenesis related protein 1 (PR1), indicating the activation of plant defence responses mediated by jasmonic and salicylic acid pathways.
The overexpression of both genes suggested a putative early activation of ISR.
Authors
A. Pasqualini, G. Manganiello, A. Pentangelo, C. Pane
Keywords
agroecology, Diplotaxis tenuifolia, Fusarium oxysporum f. sp. raphani, preharvest management, Trichoderma
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