The ability of phytopathogenic bacteria to survive for long time within asymptomatic host plants represents one of the main critical factors to control outbreaks. The epidemiological role of the bacterial latency phase is very important since the control strategies are based on preventive chemical treatments by spraying on plant surfaces. In seven-year-old plants of Actinidia chinensis var. chinensis ‘Hort16A’ inoculated five years before with a virulent Pseudomonas syringae pv. actinidiae gfp-expressing/rifampicin-resistant strain (Psagfp-Rifres) at low inoculum dose, the dangerous latency phase of Psagfp-Rifres was studied dissecting the whole plants by cutting, from the apex to the root collar, the shoots/stems in segments of 20 cm (approx. 10-15/plant). In this study, to better clarify the endophyte distribution in asymptomatic plants and the preference of the pathogen for certain portions of the plant stem, the data previously obtained from microbiological (direct isolation on selective media, DI), biological (pathogenicity/HR assay) and PCR (Bio- and Nested) analyses were compared with those from Real-time PCR (RT-PCR) analysis. In the pathosystem Psa–Actinidia, the pathogen reached a high degree of pathoadaptation which is highlighted by the pluriannual latency period of Psa. The RT-PCR of the DNA extracted and quantified by the different segments of each entire plant confirmed the results previously obtained from microbiological and Bio/Nested PCR analyses and allowed to detect Psagfp-Rifres in segments of the stem that in Bio/Nested PCR analyses were Psagfp-Rifres-negative. Direct isolation revealed the Psagfp-Rifres presence in accordance with the RT-PCR data. The long time required for DI of Psagfp-Rifres from plant samples five years after the plant inoculation was largely compatible with the low concentrations of Psagfp-Rifres detected by RT-PCR.

Endophytic distribution of Pseudomonas syringae pv. actinidiae after a five-year latency into Actinidia chinensis var. chinensis plants: a real-time-PCR analysis / Minardi Paola, Loreti Stefania, Modesti Vanessa, Biondi Enrico, Ardizzi Stefano. - STAMPA. - (2022), pp. S3A-P9.110-S3A-P9.110. (Intervento presentato al convegno 14th International Conference on Plant Pathogenic Bacteria (ICPPB) tenutosi a Assisi nel 3-8 luglio 2022).

Endophytic distribution of Pseudomonas syringae pv. actinidiae after a five-year latency into Actinidia chinensis var. chinensis plants: a real-time-PCR analysis

Minardi Paola
;
Biondi Enrico;Ardizzi Stefano
2022

Abstract

The ability of phytopathogenic bacteria to survive for long time within asymptomatic host plants represents one of the main critical factors to control outbreaks. The epidemiological role of the bacterial latency phase is very important since the control strategies are based on preventive chemical treatments by spraying on plant surfaces. In seven-year-old plants of Actinidia chinensis var. chinensis ‘Hort16A’ inoculated five years before with a virulent Pseudomonas syringae pv. actinidiae gfp-expressing/rifampicin-resistant strain (Psagfp-Rifres) at low inoculum dose, the dangerous latency phase of Psagfp-Rifres was studied dissecting the whole plants by cutting, from the apex to the root collar, the shoots/stems in segments of 20 cm (approx. 10-15/plant). In this study, to better clarify the endophyte distribution in asymptomatic plants and the preference of the pathogen for certain portions of the plant stem, the data previously obtained from microbiological (direct isolation on selective media, DI), biological (pathogenicity/HR assay) and PCR (Bio- and Nested) analyses were compared with those from Real-time PCR (RT-PCR) analysis. In the pathosystem Psa–Actinidia, the pathogen reached a high degree of pathoadaptation which is highlighted by the pluriannual latency period of Psa. The RT-PCR of the DNA extracted and quantified by the different segments of each entire plant confirmed the results previously obtained from microbiological and Bio/Nested PCR analyses and allowed to detect Psagfp-Rifres in segments of the stem that in Bio/Nested PCR analyses were Psagfp-Rifres-negative. Direct isolation revealed the Psagfp-Rifres presence in accordance with the RT-PCR data. The long time required for DI of Psagfp-Rifres from plant samples five years after the plant inoculation was largely compatible with the low concentrations of Psagfp-Rifres detected by RT-PCR.
2022
Book of Abstracts: 14th International Conference on Plant Pathogenic Bacteria (ICPPB) "The Impact of Plant Pathogenic Bacteria on Global Planth Health"
110
110
Endophytic distribution of Pseudomonas syringae pv. actinidiae after a five-year latency into Actinidia chinensis var. chinensis plants: a real-time-PCR analysis / Minardi Paola, Loreti Stefania, Modesti Vanessa, Biondi Enrico, Ardizzi Stefano. - STAMPA. - (2022), pp. S3A-P9.110-S3A-P9.110. (Intervento presentato al convegno 14th International Conference on Plant Pathogenic Bacteria (ICPPB) tenutosi a Assisi nel 3-8 luglio 2022).
Minardi Paola, Loreti Stefania, Modesti Vanessa, Biondi Enrico, Ardizzi Stefano
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11585/891117
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