Articles
IDENTIFICATION AND COMPARISON OF DIFFERENT PRUNUS PHYTOPLASMA DISEASES BY INDEXING ON GF305 PEACH SEEDLINGS IN THE GREENHOUSE
Article number
472_96
Pages
723 – 730
Language
Abstract
For 30 years, Ctifl has used GF305 peach seedlings to detect pathogenic agents causing degenerative diseases on Prunus. Forty to 60 day old plants were indexed by chip budding, then cut back 14 days later.
Budded seedlings showed foliar symptoms and/or growth modification to about thirty diseases within 30 to 120 days (Boyé and Desvignes, 1996). In the present study, we have compared 5 known Prunus phytoplasma diseases and which were originally identified from their symptoms on stone fruits: apricot chlorotic leaf roll (ACLR), Japanese plum decline (JPD), peach vein clearing (PVC), peach yellow (PY), peach yellow leaf roll (PYLR). At three different periods of the year, from 3 to 4 months after indexing, the inoculated GF305 plants showed several symptoms leading to the classification into 4 different groups of phytoplasmas: ACLR, PVC-JPD, PY, and PYLR. Depending on the pathogen, we observed: chlorotic leaf roll followed (ACLR, PYLR) or not (PVC) by reddening and necrotic spots on leaves (PYLR), chlorosis with prominent jutting veins (ACLR, PVC, PYLR), small and narrow chlorotic leaves (PY), poor stem lignification (ACLR, PVC, PYLR), plant wilt (ACLR) and lateral shoots start (ACLR, PY). The DAPI test was used to confirm the infection by phytoplasmas in symptomatic plants.
It was positive with ACLR, PVC-JPD, PYLR, but negative with PY. An approach survey of frequency and natural hosts in France of these diseases was also investigated.
This study confirms that GF305 peach seedlings, with homogenous growth and being easy to use, can be employed throughout the year in a climate-controlled greenhouse for detection and identification of these 5 different phytoplasma diseases.
The different symptoms we observed are reliable and reproducible.
Symptoms can be easily characterized and distinguished by the trained eye.
Budded seedlings showed foliar symptoms and/or growth modification to about thirty diseases within 30 to 120 days (Boyé and Desvignes, 1996). In the present study, we have compared 5 known Prunus phytoplasma diseases and which were originally identified from their symptoms on stone fruits: apricot chlorotic leaf roll (ACLR), Japanese plum decline (JPD), peach vein clearing (PVC), peach yellow (PY), peach yellow leaf roll (PYLR). At three different periods of the year, from 3 to 4 months after indexing, the inoculated GF305 plants showed several symptoms leading to the classification into 4 different groups of phytoplasmas: ACLR, PVC-JPD, PY, and PYLR. Depending on the pathogen, we observed: chlorotic leaf roll followed (ACLR, PYLR) or not (PVC) by reddening and necrotic spots on leaves (PYLR), chlorosis with prominent jutting veins (ACLR, PVC, PYLR), small and narrow chlorotic leaves (PY), poor stem lignification (ACLR, PVC, PYLR), plant wilt (ACLR) and lateral shoots start (ACLR, PY). The DAPI test was used to confirm the infection by phytoplasmas in symptomatic plants.
It was positive with ACLR, PVC-JPD, PYLR, but negative with PY. An approach survey of frequency and natural hosts in France of these diseases was also investigated.
This study confirms that GF305 peach seedlings, with homogenous growth and being easy to use, can be employed throughout the year in a climate-controlled greenhouse for detection and identification of these 5 different phytoplasma diseases.
The different symptoms we observed are reliable and reproducible.
Symptoms can be easily characterized and distinguished by the trained eye.
Authors
P. Gentit, D. Cornaggia, J.C. Desvignes
Keywords
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