Fungal endophytic community associated with guarana (Paullinia cupana var. Sorbilis): diversity driver by genotypes in the centre of origin

Guarana plant is a native of the Amazon region. Due to its high amount of caffeine and tannins, the seed has medicinal and stimulating properties. The guarana industry has grown exponentially in recent years; however, little information is available about associated mycobiota, particularly endophytic fungi. The present study aimed to compare the distribution and diversity of endophytic fungi associated with the leaves and seeds of anthracnose-resistant and susceptible guarana plants produced in Maués and Manaus, Amazonas State, Brazil. A total of 7514 endophytic fungi were isolated on Potato Dextrose Agar, Sabouraud and Czapek media, and grouped into 77 morphological groups. Overall, fungal communities in guarana leaves and seeds were mainly composed by Colletotrichum and Fusarium genera, but also by Chondrostereum, Clonostachys, Curvularia, Hypomontagnella, Lentinus, Neopestalotiopsis, Nigrospora, Peroneutypa, Phyllosticta, Simplicillium and Tinctoporellus. Obtained results indicate that some members of Colletotrichum and Fusarium genera may have experienced dysbiosis during the guarana domestication process, suggesting that some individuals may behave as latent pathogens. The susceptible guarana genotype cultivated in Manaus presented higher fungal diversity. The relative abundance of taxa and diversity among samples suggests that communities are structured by genotype and geographic location. This is the first report of mycobiota in both guarana leaves and seeds.This research was funded by the Coordenação de Aperfeiçoamento de Pessoal de Nível Superior(CAPES) project Pró-Amazônia n◦3287/13. C.S. (Carla Santos) and N.L. were supported by FCT under the scopeof the strategic funding of UIDB/04469/2020 unit and BioTecNorte operation (NORTE-01-0145-FEDER-000004)funded by the European Regional Development Fund under the scope of Norte2020 - Programa OperacionalRegional do Norte. C.S. (Cledir Santos) was supported by the Universidad de La Frontera (Temuco, Chile) withpartial funding from the Project PIA19-0001.info:eu-repo/semantics/publishedVersio

Análises em nível de comunidade, populacional e indivíduo para melhor compreensão do Mal-das-folhas da seringueira e de seu agente etiológico, Pseudocercospora ulei

Pseudocercospora ulei causes the most devastating disease of the rubber tree (Hevea brasiliensis), South American leaf blight (SALB). Wild populations of H. brasiliensis from different river basins in the Amazon region have variable resistance levels to SALB, and the most resistant genotypes were found in the western Amazon, including the Brazilian state of Acre. Based on the premise that the plant microbiome can directly influence the plant-pathogen interactions and contribute to disease-resistance, we studied the endophytic microbiome of wild H. brasiliensis from three Amazonian states in Brazil. The diversity of fungal and prokaryotic endophytes was shaped by plant organ (leaf, sapwood or root) and there is strong evidence that the microbial communities from trees collected in Acre are markedly distinct and more diverse than those from the states of Amazonas and Pará. This pattern may be a function of geographic isolation influenced by differences in the geological history of eastern and western Amazon. Functional prediction revealed important roles of endophytes associated with disease suppressiveness, biological control, but also with pathogenesis. We also studied the allelic variation in five effector proteins genes conserved in Dothideomycetes between pathogen populations from Amazon region (AM) and commercial plantations located in the Northeast and Southeast regions in Brazil (N-AM). The analyzes showed the highest polymorphism in three effector genes (PuAve1, PuEcp2 and PuEcp6) and a pattern of division between groups of haplotypes of the AM and N-AM populations. The diversification in P. ulei effector genes is driven for intragenic recombination and selection, and two different mechanisms to avoid the recognition by rubber tree were detected in P. ulei populations. Characterization of melanin pigment with mass spectrometry (MALDI-TOF) and infrared (IR) have failed but revealed that data on beta-glucans have apparently been mistakenly assigned to melanin in recent reports in the literature. Using a specific inhibitor of melanization, we have found that the melanin present in P. ulei is made from1,8-dihydroxynaphthalene (1,8-DHN) and the genes involved in this biosynthetic pathway were mapped into the fungus genome. Taken together, our results provide new and important information about the microbial components (pathogen and whole microbiota) of the yet neglected SALB pathosystem.Pseudocercospora ulei causa a doença conhecida como Mal-das-Folhas (em inglês, South American Leaf Blight - SALB) da seringueira (Hevea brasiliensis). Populações nativas de H. brasiliensis de diferentes bacias hidrográficas da Amazônia apresentam níveis de resistência variáveis a SALB, e os genótipos mais resistentes foram encontrados na Amazônia Ocidental, incluindo o estado do Acre. Baseado na premissa de que o microbioma da planta pode influenciar diretamente as interações planta-patógeno e contribuir para a resistência a doenças, realizou-se um estudo com DNA metabarcoding de endofíticos de H. brasiliensis nativas de três estados da Amazônia brasileira. A diversidade de endófitos fúngicos e procarióticos foi modelada por órgão da planta (folha, alburno ou raiz trófica). As comunidades microbianas das árvores coletadas no Acre foram distintas e mais diversificadas que as dos estados do Amazonas e Pará. Este resultado pode ser consequência do isolamento geográfico influenciado por diferenças na história geológica da Amazônia Oriental e Ocidental. A predição funcional revelou importantes papéis dos endofíticos, associados à supressividade da doença, controle biológico, mas também à patogênese. Estudou-se também a variação alélica de cinco genes que codificam proteínas efetoras conservadas em Dotideomicetos em populações do patógeno da região amazônica (AM) e plantios comerciais localizados nas regiões Nordeste e Sudeste do Brasil (N-AM). As análises mostraram um maior polimorfismo em três genes efetores (PuAve1, PuEcp2 e PuEcp6) e um padrão de divisão entre grupos de haplótipos das populações AM e N-AM. A diversificação em genes efetores de P. ulei é dirigida por recombinação intragênica e seleção, e dois mecanismos para evitar o reconhecimento pela seringueira foram detectados em populações de P. ulei. Por fim, investigamos o processo de melanização do patógeno. A caracterização da melanina utilizando espectrometria de massa (MALDI-TOF) e Infravermelho (IR) falhou, mas revelou que os dados sobre beta-glucanas aparentemente foram erroneamente atribuídos à melanina em relatos recentes da literatura. Usando um inibidor específico de melanização (Triciclazol), verificou-se que a melanina presente em P. ulei é produzida a partir de 1,8-di-hidroxinaftaleno (1,8-DHN) e os genes envolvidos nesta via biossintética foram mapeados no genoma do fungo. Assim, nossos resultados fornecem informações novas e importantes sobre os componentes microbianos (patógeno e microbiota total) deste patossistema negligenciado.Coordenação de Aperfeiçoamento de Pessoal de Nível Superio