Analise de genes diferencialmente expressos na interaçao Hevea brasiliensis - Microcyclus ulei

De Andrade Junior Sizenando Jose. 2008. Analise de genes diferencialmente expressos na interaçao Hevea brasiliensis - Microcyclus ulei. Ilhéus : UESC, 74 p. Dissertaçao Mestre : Genetica e Biologia Molecular : Universidade Estadual de Santa Cruz

Résumé : The South American Leaf Blight caused by Mycrocyclus ulei is one of the main diseases that affect the Hevea plants, and it represents a great threat for the world production of natural latex. The main alternative to fight this disease is related to genetic breeding of rubber tree to obtain durable resistant clones. Previous genetic mapping and QTL detection studies showed that the resistance to M. ulei involved, at least, three chromosome regions, and that a better understanding of the genetic bases involved in this interaction is necessary for an effective disease control. An efficient strategy to elucidate the resistance mechanisms consists in the identification of genes differentially expressed between genotypes with contrasting responses to pathogen attack. The production of expressed sequence tags (ESTs) and global transcriptomic analysis are efficient and powerful strategies to identify genes regulated by biotic or abiotic stresses. Moreover, the use of the suppression substractive hybridization (SSH) increased gene characterization and allowed the generation of sequence information for micro- and macroarrays design and genomic annotation. This allows the analyses of large scale gene interactions. The present work lead with the identification of unigene ESTs for each cultivar; particular attention was given to ESTs with function related to defence responses, cell signalization, 14 transport and hormone pathways, obtained from 4-28 d.a.i. Hevea-Microcyclus SSH libraries. In the resistant cultivar, 31 sequences homologous to defence genes, 7 to genes involved in hormone pathways, 12 related to gene transport and 19 to signalization pathway were identified. In the susceptible cultivar, the number of sequences was lower (4): 2 showing homology with defence genes, 1 with protein transport and 1 involved in signalization apparatus. In this cultivar, no original sequence related to hormone pathways was observed. Afterwards, functional analyses of these sequences via macroarrays were made. Unigene sets of sequences were obtained, submitted to plasmid DNA extraction, polymerase chain reaction for fragment amplification and finally, denatured with NaOH and fixed in Nylon membranes. The cDNA used in the hybridization process were synthesized from rubber tree leaf transcriptomes (from the partially resistant clone, MDF180, and the susceptible one, PB 314) infected with M. ulei (10 d.a.i.). These cDNAs were hybridized on the membranes using the AlkPhos kit (GE Healthcare, USA). The results showed a differential expression between resistant and susceptible clones for 31 sequences: 18 from stress-defence functional class; 7 from signalization; 4 from transport; and 2 from hormone pathways. The durable resistance observed in the MDF 180 cultivar may be the consequence of higher amount of genes and higher gene expression of defence, signalization, transport and hormone pathways found in this cultivar.

Mots-clés Agrovoc : Hevea brasiliensis, Microcyclus ulei

Mots-clés géographiques Agrovoc : Brésil

Classification Agris : H20 - Maladies des plantes
F30 - Génétique et amélioration des plantes

Champ stratégique Cirad : Axe 1 (2005-2013) - Intensification écologique

Auteurs et affiliations

• De Andrade Junior Sizenando Jose, UESC (BRA)

Source : Cirad - Agritrop (https://agritrop.cirad.fr/553113/)

Métriques

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