Submitted by Angela Maria de Oliveira (amolivei@uepg.br) on 2018-07-24T18:20:09Z No. of bitstreams: 2 license_rdf: 811 bytes, checksum: e39d27027a6cc9cb039ad269a5db8e34 (MD5) Fabiane Paulitsch.pdf: 1288582 bytes, checksum: c019c172d12983ecb197493b2d5df4d8 (MD5) / Made available in DSpace on 2018-07-24T18:20:09Z (GMT). No. of bitstreams: 2 license_rdf: 811 bytes, checksum: e39d27027a6cc9cb039ad269a5db8e34 (MD5) Fabiane Paulitsch.pdf: 1288582 bytes, checksum: c019c172d12983ecb197493b2d5df4d8 (MD5) Previous issue date: 2017-02-22 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Levantamentos florísticos realizados nos “Campos Gerais” (Paraná, Brasil) indicam que Fabaceae é uma das famílias com maior riqueza e abundância da região. Esses estudos também apontam a elevada diversidade e endemismo de Mimosa spp. Nosso estudo relata a diversidade de rizóbios isolados de nódulos radiculares de plantas nativas de Mimosa gymnas Barneby. Vinte e nove estirpes foram obtidas de M. gymnast nodulíferas em três áreas do Parque Estadual do Guartelá, uma das mais importantes unidades de conservação dos Campos Gerais; os solos dessas áreas foram caracterizados como arenosos, ácidos, pobre em nutrientes e matéria orgânica e com elevados teores de alumínio. A árvore filogenética construída com sequencias parciais do gene 16S rDNA agrupou as estirpes em um grande clado sendo que algumas estipes foram mais relacionados com a espécie Paraburkholderia nodosa enquanto outras foram mais relacionadas com P. bannensi. A análise de perfil genômico baseada em BOX-PCR revelou um elevado grau de variabilidade intraespecífica entre os isolados. Resultados baseados na filogenia de sequencias concatenadas dos genes recA-gyrB dividiram os isolados em dois grandes grupos. O clado II não agrupou nenhuma estirpe tipo e os isolados apresentaram uma identidade nucleotídica de no máximo 97% com P. nodosa. A filogenia do gene nodC agrupou todos os isolados em um grupo único com elevado suporte estatístico, não agrupando com a sequencia correspondente de nenhuma estirpe tipo do gênero Paraburkholderia. Nossos resultados reforçam a constatação de que rizóbios do gênero Paraburkholderia são os preferenciais simbiontes de Mimosa na América do Sul e a associação de estirpes nodulíferas do gênero com condições edáficas particulares. Ainda, os resultados das análises filogenéticas sugerem que os isolados agrupados no clado II na árvore filogenética dos genes recA-gyrB podem representar uma nova espécie de Paraburkholderia, reinterando a importância de estudos de diversidade com plantas leguminosas nativas e endêmicas. . / Floristic surveys performed in the “Campos Gerais” (Paraná, Brazil) indicate that Fabaceae is one of the most species-rich and abundant families. These studies also pointed out the high diversity and endemism of Mimosa spp. Our study report the diversity of rhizobia isolated from root nodules of native Mimosa gymnas Barneby. Twenty-nine strains were obtained from from nodulating M. gymnas in three areas of Guartelá State Park, one of the most important conservation unities of the “Campos Gerais”; soils of these areas were characterized as sandy, acid, poor in nutrients and organic matter and with high aluminum contents. The phylogenetic tree constructed with partial 16S rDNA sequences grouped the strains in a larger cluster and some strains were more related with Paraburkholderia nodosa, although some strains were more related to P. bannensi. The analysis of the genomic profile by BOX-PCR revelead a high degree of intraspecific variability among the isolates. Results based on phylogeny of concatened genes recA-gyrB divided the strains in two large clusters. The cluster II didn’t grouped with any type strain and the isolates showed a nucleotide identity of 16S rDNA of at most 97% with P. nodosa. The nodC phylogeny grouped all the strains into a well-supported clade, not grouping with any know strain of Paraburkholderia genus. Our results support that Paraburkholderia are the main symbionts of Mimosa in South America and the association of nodulating strains of this genera with particular edaphic conditions. Also, the results of the phylogenetic analysis suggest that the isolates grouped in cluster II in the recA-gyrB phylogenetic tree may represent a new species of Paraburkolderia, highlighting the importance of diversity studies with native and endemic leguminous plants.

Paraburkholderia phytofirmans souche PsJN est une bactérie endophyte capable d’induire une promotion de croissance de la vigne et de lui conférer une tolérance vis-à-vis des basses températures. Puisque la bactérie PsJN induit également une tolérance de la vigne contre la pourriture grise causée par le champignon Botrytis cinerea, l’objectif de ce travail était de caractériser les mécanismes de la résistance induite par P. phytofirmans suite à une infection par B. cinerea chez la vigne.Nos résultats indiquent que l’inoculation des racines de vitroplants par la bactérie PsJN entraîne des modifications du métabolisme phénolique au niveau des plantules bactérisées. En effet, des tanins d’origine gallique et ellagique sont accumulés au niveau des racines en réponse à PsJN alors qu’une accumulation de lignine a été observée dans la tige et d’anthocyanes dans les feuilles. De même, PsJN induit une résistance contre B. cinerea en potentialisant l'expression de gènes de défense dépendants de l’acide salicylique et de l’acide jasmonique dans les feuilles de vigne. Parallèlement, une accumulation de callose et d’H2O2 a été observée ainsi qu’une meilleure mobilisation des glucides dans les plantules bactérisées, corrélée à une réduction des dommages de l’activité photosynthétique.Suite aux résultats obtenus avec le modèle vitroplant, nous avons optimisé la bactérisation des boutures fructifère et évaluer l’impact de cette bactérie sur la résistance des inflorescences contre B. cinerea. Les résultats présentés dans ce travail permettent d’envisager l’utilisation de la bactérie PsJN comme agent de lutte biologique. / Paraburkholderia phytofirmans strain PsJN is an endophytic beneficial bacterium able to promote the growth of grapevine and to induce the plant resistance to biotic and abiotic stresses. Indeed, the interaction between PsJN and grapevine confers to the grapevine a protection towards cold stress (4 °C), by reducing damages on the photosynthetic system and modulating the carbon metabolism. The PsJN strain also induces a protection against gray mold caused by Botrytis cinerea. In this context, the aim of this work was to better characterize this P. phytofirmans strain PsJN-induced resistance in grapevine against B. cinerea.Our results indicate that the inoculation of in vitro-plantlets roots with PsJN altered the phenolic metabolism in bacterized-plantlets. Gallic and ellagic derived tannins are clearly accumulated in roots of bacterized-plantlets whereas an accumulation of lignin in stems and anthocyanins in leaves was observed. We also showed that PsJN induces a protection against B. cinerea by priming the expression of genes involved in salicylic acid and jasmonic acid pathways. In parallel, an accumulation of callose and H2O2, as well as a better mobilization of carbohydrates in bacterized plantlets were observed. In addition to the defense mechanisms setting up by plants, we demonstrated that PsJN reduces in vitro and in vivo development of B. cinerea, in a dose-dependent manner.Following results obtained with the in vitro-plantlets model, we optimized the protocol of bacterization of grapevine fruiting cuttings by the PsJN strain, and evaluate the impact of the bacteria on to induce the resistance of inflorescences to B. cinerea. Our results provide new insights for the use of PsJN and suggest its commercial use as a biological control agent.

Acacia spirorbis est une légumineuse endémique de Nouvelle-Calédonie se développant sur des sols calcaires, métallifères et volcano-sédimentaires, établissant des symbioses avec des bactéries fixatrices d’azote. Pour comprendre la contribution de la symbiose dans l’adaptation de la plante à des milieux contrastés et parfois extrêmes, nous avons évalué la fixation d’azote en conditions naturelles, caractérisé les rhizobia associés à cette plante et analysé la réponse adaptative de la plante aux éléments traces métalliques dans ses tissus racinaires, notamment au niveau des nodules.Nous avons mis en évidence que la symbiose rhizobienne fournissait plus de 80% de l’azote total chez des populations naturelles d’A. spirorbis se développant sur des sites d’études présentant des sols calcaires, métallifères et volcano-sédimentaires. Cette valeur est remarquable puisque chez A. mangium, A. melanoxylon et A. mucronata, les valeurs moyennes sont respectivement de 50%, 43% et 58%. Les rhizobia symbiotiques associés à A. spirorbis appartiennent aux alpha- et bêta-protéobactéries, genres Bradyrhizobium et Paraburkholderia, révélant ainsi une très large gamme de symbiontes et une faible sélectivité de partenaire. De manière remarquable, la taxonomie et la phénotypie de ces souches sont structurées et adaptées aux conditions édaphiques. Enfin, les signatures chimiques des tissus internes des nodules reflètent les propriétés chimiques des sols dans lesquels ils se sont développés, indiquant une potentielle gestion des éléments traces métalliques dans ces tissus.Tous ces éléments suggèrent que la symbiose fixatrice d’azote contribue de manière significative dans l’adaptation d’Acacia spirorbis à des sols contrastés et pouvant présenter une toxicité polymétallique extrême. / Acacia spirorbis is a leguminous tree from New Caledonia naturally found on a wide range of soils (calcareous, ultramafic and volcano-sedimentary) and able to establish symbioses with soil microorganisms, including nitrogen-fixing bacteria. The contribution of this symbiosis in the plant adaptation to contrasted edaphic environments, sometimes extremes, has been investigated according to i) the nitrogen-fixing potential of A. spirorbis in its natural ecosystems, ii) the characterization of its rhizobia and iii) the plant adaptive response to heavy metals inside its roots tissues, especially in nodules.Therefore, we revealed that the nitrogen-fixing symbiosis provided more than 80% of the plant total nitrogen in natural population naturally occurring on calcareous, ultramafic and volcano-sedimentary soils. This value is top notch among other Acacia species, where A. mangium, A. melanoxylon and A. mucronata presented mean values of 50%, 43% and 58%, respectively. Acacia spirorbis established nitrogen-fixing symbioses with alpha- and bêta-proteobacteria, genus Bradyrhizobium and Paraburkholderia, respectively, thus revealing a wide range of symbiotic partner and a low selectivity. Noteworthy, the taxonomy and phenotypes of these symbionts are structured and adapted to edaphic parameters. Finally, chemical signatures of internal nodules tissues presented similarities with soils chemical properties, thus indicating a potential management of heavy metals inside these tissues.Altogether, these data suggest that the nitrogen-fixing symbiosis might significantly contributes to Acacia spirorbis adaptation towards contrasted soils with strong edaphic conditions as an extreme polymetallic toxicity.