How anthropogenic changes may affect soil-borne parasite diversity? Plant-parasitic nematode communities associated with olive trees in Morocco as a case study.
Plant-parasitic nematodes (PPN) are major crop pests. On olive (Olea europaea), they significantly contribute to economic losses in the top-ten olive producing countries in the world especially in nurseries and under cropping intensification. The diversity and the structure of PPN communities respond to environmental and anthropogenic forces. The olive tree is a good host plant model to understand the impact of such forces on PPN diversity since it grows according to different modalities (wild, feral and cultivated olives). A wide soil survey was conducted in several olive-growing regions in Morocco. The taxonomical and the functional diversity as well as the structures of PPN communities were described and then compared between non-cultivated (wild and feral forms) and cultivated (traditional and high-density olive cultivation) olives.



A high diversity of PPN with the detection of 117 species and 47 genera was revealed. Some taxa were recorded for the first time on olive trees worldwide and new species were also identified. Anthropogenic factors (wild vs cultivated conditions) strongly impacted the PPN diversity and the functional composition of communities because the species richness, the local diversity and the evenness of communities significantly decreased and the abundance of nematodes significantly increased in high-density conditions. Furthermore, these conditions exhibited many more obligate and colonizer PPN and less persister PPN compared to non-cultivated conditions. Taxonomical structures of communities were also impacted: genera such as Xiphinema spp. and Heterodera spp. were dominant in wild olive, whereas harmful taxa such as Meloidogyne spp. were especially enhanced in high-density orchards.



Olive anthropogenic practices reduce the PPN diversity in communities and lead to changes of the community structures with the development of some damaging nematodes. The study underlined the PPN diversity as a relevant indicator to assess community pathogenicity. That could be taken into account in order to design control strategies based on community rearrangements and interactions between species instead of reducing the most pathogenic species.
Plant Protection Department, Faculty of Agriculture, Tishreen University, PO Box 2233, Latakia, Syrian Arab Republic. nadineali.tichrine.univ@gmail.com.|IRD, UMR CBGP, 755 Avenue du Campus Agropolis, CS30016, 34988, Montferrier-sur-Lez Cedex, France. nadineali.tichrine.univ@gmail.com.
Nadine
N
Ali
IRD, UMR CBGP, 755 Avenue du Campus Agropolis, CS30016, 34988, Montferrier-sur-Lez Cedex, France.
Johannes
J
Tavoillot
CNRS, UMR EDB, Université Toulouse III Paul Sabatier, Bâtiment 4R1, 118 Route de Narbonne, 31062, Toulouse Cedex 9, France.
Guillaume
G
Besnard
UMR AGAP, SUPAGRO, Campus CIRAD, TAA-108/03, Avenue Agropolis, 34398, Montpellier Cedex 5, France.
Bouchaib
B
Khadari
Museum and Institute of Zoology PAS, Wilcza 64, 00-679, Warsaw, Poland.
Ewa
E
Dmowska
Museum and Institute of Zoology PAS, Wilcza 64, 00-679, Warsaw, Poland.
Grażyna
G
Winiszewska
IRD, UMR CBGP, 755 Avenue du Campus Agropolis, CS30016, 34988, Montferrier-sur-Lez Cedex, France.
Odile
O
Fossati-Gaschignard
Faculté des Sciences et Techniques, Université Abdelmalek Essaadi, BP 2062, 93030, Tétouan, Morocco.
Mohammed
M
Ater
Laboratoire LBVRN, Faculté des Sciences d'Agadir, Université Ibn Zohr, BP 8106, 80000, Agadir, Morocco.
Mohamed
M
Aït Hamza
Laboratoire LBVRN, Faculté des Sciences d'Agadir, Université Ibn Zohr, BP 8106, 80000, Agadir, Morocco.
Abdelhamid
A
El Mousadik
INRA, CRRA, BP 513, 40000, Marrakech, Morocco.
Aïcha
A
El Oualkadi
INRA, CRRA, BP 513, 40000, Marrakech, Morocco.
Abdelmajid
A
Moukhli
UMR AGAP, SUPAGRO, Campus CIRAD, TAA-108/03, Avenue Agropolis, 34398, Montpellier Cedex 5, France.
Laila
L
Essalouh
INRA, UMR APCRPG, BP 578, 50000, Meknes, Morocco.
Ahmed
A
El Bakkali
IRD, UMR CBGP, 755 Avenue du Campus Agropolis, CS30016, 34988, Montferrier-sur-Lez Cedex, France.|IRD, UMR IPME (IRD/Université de Montpellier/CIRAD), 911 Avenue Agropolis, BP 64501, 34394, Montpellier Cedex 5, France.|UMR PVBMT, 3P-CIRAD, 7 chemin de l'Irat, Ligne paradis, 97410, Saint Pierre, Réunion.
Elodie
E
Chapuis
IRD, UMR CBGP, 755 Avenue du Campus Agropolis, CS30016, 34988, Montferrier-sur-Lez Cedex, France.
Thierry
T
Mateille
D000818:Animals; D044822:Biodiversity; D009018:Morocco; D009348:Nematoda / Q000502:physiology*; D031658:Olea / Q000469:parasitology* / Q000502:physiology; D010935:Plant Diseases / Q000469:parasitology*; D012987:Soil / Q000737:chemistry / Q000469:parasitology*
D012987:Soil
Anthropisation; Communities; Functional diversity; Morocco; Olive; Plant-parasitic nematodes; Taxonomical structures