Les techniques de régénération du chêne-liège au Maroc

Les suberaies jouent au Maroc un rôle économique et social très important. Or, comme dans les autres pays du Sud, elles sont soumises à de fortes pressions et dégradations. C’est pourquoi les autorités marocaines ont entrepris un vaste programme de régénération artificielle du chêne-liège par plantation. Cet effort est accompagné par des travaux de recherche en matière de production de plants et de conduite de peuplement

The endemic Chamaecytisus albidus is nodulated by symbiovar genistearum of Bradyrhizobium in the Moroccan Maamora Forest

Out of 54 isolates from root nodules of the Moroccan-endemic Chamaecytisus albidus plants growing in soils from the Maamora cork oak forest, 44 isolates formed nodules when used to infect their original host plant. A phenotypic analysis showed the metabolic diversity of the strains that used different carbohydrates and amino acids as sole carbon and nitrogen sources. The isolates grew on media with pH values ranging from 6 to 8. However, they did not tolerate high temperatures or drought and they did not grow on media with salt concentrations higher than 85 mM. REP-PCR fingerprinting grouped the strains into 12 clusters, of which representative strains were selected for ARDRA and rrs analyses. The rrs gene sequence analysis indicated that all 12 strains were members of the genus Bradyrhizobium and their phylogeny showed that they were grouped into two different clusters. Two strains from each group were selected for multilocus sequence analysis (MLSA) using atpD, recA, gyrB and glnII housekeeping genes. The inferred phylogenetic trees confirmed that the strains clustered into two divergent clusters. Strains CM55 and CM57 were affiliated to the B. canariense/B. lupini group, whereas strains CM61 and CM64 were regrouped within the B. cytisi/B. rifense lineage. The analysis of the nodC symbiotic gene affiliated the strains to the symbiovar genistearum. The strains were also able to nodulate Retama monosperma, Lupinus luteus and Cytisus monspessulanus, but not Phaseolus vulgaris or Glycine max. Inoculation tests with C. albidus showed that some strains could be exploited as efficient inocula that could be used to improve plant growth in the Maamora forest.The authors want to thank all the people who contributed to theachievement of this study. Financial support was obtained from‘‘Académie Hassan II des Sciences et Techniques” (Morocco). MrOmar Bouhnik received a grant from the Hassan II Academy of Science and Technology. The authors also thank the Ministerio de Economía, Industria y Competitividad (Spain) for the granting ofthe ERDF-cofinanced project AGL2017–85676R

Les techniques de régénération du chêne-liège au Maroc

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