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sur le développement des zones arides et semi-arides

Titre : Diversidad bacteriana asociada a rizósfera de papaya (Carica papaya l.) en tres etapas fenológicas

Auteur : Garavito Parra, Martha Ligia

Etablissement de soutenance : Centro de Investigaciones Biológicas del Noroeste (CIBNOR)

Grade : Maestría en Ciencias en el Uso, Manejo y Preservación de los Recursos Naturales 2007

Résumé
Papaya (Carica papaya L) is the third most important tropical fruit in the world. Mexico holds second rank in world-wide production, which has generated an increased interest in the development of biotechnology mainly focused on the use of microorganisms to improve crop productivity. Bacteria play a central role in nutrition, health, and plant growth through their association with the root zone. The purpose of this research was to determine, by a combination of traditional cultivation techniques, 16S rDNA identification using SSCP analysis, and followed by sequencing of possible dominant bacteria, the different and dominant bacterial populations associated with the papaya rhizosphere at three phenological stages (vegetative, flowering, and fruiting) and between the plant sexes after the flowering stage. To reduce the complexity of SSCP fingerprints and to analyze specific populations, specific primers for different phylogenetic groups were used. The comparison of SSCP patterns indicated that the composition of the rhizosphere community of bacteria, analyzed at different plant growth stages, was different. Comparison of 16S genes obtained by amplification of universal and α-Proteobacterial primers between sexes also showed differences. However, the profiles for the Pseudomonas group remained constant throughout the three phenological stages and between plant sexes. In comparison with the SSCP analysis, microbiological methods were unable to detect differences in bacterial composition between the three stages.

Mots Clés : Diversidad bacteriana ; rizósfera ; Papaya

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