Characterization of <i>Phytophthora</i> and <i>Pythium</i> Species Associated with Root Rot of Olive Trees in Morocco
The olive tree is one of the most important fruit crops grown in Morocco, yet extensive decline associated with the root rot of this crop has been observed in many regions. This study aimed to identify and characterize the oomycetes associated with root rot disease in olive trees. During the 2021 an...
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| Main Authors: | , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
MDPI AG
2025-02-01
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| Series: | Agriculture |
| Subjects: | |
| Online Access: | https://www.mdpi.com/2077-0472/15/4/435 |
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| Summary: | The olive tree is one of the most important fruit crops grown in Morocco, yet extensive decline associated with the root rot of this crop has been observed in many regions. This study aimed to identify and characterize the oomycetes associated with root rot disease in olive trees. During the 2021 and 2022 growing seasons, symptomatic root tissues and soil samples were collected for isolation. Based on morphological traits and the sequencing of the internal transcribed spacer (<i>ITS</i>) region of rDNA, 10 oomycete species were identified, belonging to the <i>Phytophthora</i> and <i>Pythium</i> sensu lato (s.l.) genera. Seven species were assigned to <i>Phytophthora</i>, namely, <i>P. palmivora</i>, <i>P. plurivora</i>, <i>P. acerina</i>, <i>P. oleae</i>, <i>P. cactorum</i>, <i>P. gonapodyides</i>, and <i>P. megasperma</i>. The <i>Pythium</i> s.l. genus was represented by three species, including <i>P. schmitthenneri</i>, <i>P. aphanidermatum</i>, and <i>P. irregulare</i>. A pathogenicity assay was conducted by soil infestation to evaluate the effect of these pathogens on one-year-old olive saplings (var. <i>Picholine Marocaine</i>). Results revealed that all 10 species were pathogenic to olive saplings. Inoculated saplings exhibited symptoms, such as root rot, vascular discoloration, and wilting. The pathogens were successfully re-isolated from necrotic roots, thereby fulfilling Koch’s postulates. These findings highlight the complex etiology of root rot disease in olive trees, as multiple species can induce similar symptoms. This study represents the first detailed report of <i>Phytophthora</i> and <i>Pythium</i> s.l. species associated with olive root rot disease in Morocco. |
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| ISSN: | 2077-0472 |