BackgroundThe hemibiotrophic pathogens Moniliophthora perniciosa (witches’ broom disease) and Moniliophthora roreri (frosty pod rot disease) are among the most important pathogens of cacao. Moniliophthora perniciosa has a broad host range and infects a variety of meristematic tissues in cacao plants, whereas M. roreri infects only pods of Theobroma and Herrania genera. Comparative pathogenomics of these fungi is essential to understand Moniliophthora infection strategies, therefore the detection and in silico functional characterization of effector candidates are important steps to gain insight on their pathogenicity.ResultsCandidate secreted effector proteins repertoire were predicted using the genomes of five representative isolates of M. perniciosa subpopulations (three from cacao and two from solanaceous hosts), and one representative isolate of M. roreri from Peru. Many putative effectors candidates were identified in M. perniciosa: 157 and 134 in cacao isolates from Bahia, Brazil; 109 in cacao isolate from Ecuador, 92 and 80 in wild solanaceous isolates from Minas Gerais (Lobeira) and Bahia (Caiçara), Brazil; respectively. Moniliophthora roreri showed the highest number of effector candidates, a total of 243. A set of eight core effectors were shared among all Moniliophthora isolates, while others were shared either between the wild solanaceous isolates or among cacao isolates. Mostly, candidate effectors of M. perniciosa were shared among the isolates, whereas in M. roreri nearly 50% were exclusive to the specie. In addition, a large number of cell wall-degrading enzymes characteristic of hemibiotrophic fungi were found. From these, we highlighted the proteins involved in cell wall modification, an enzymatic arsenal that allows the plant pathogens to inhabit environments with oxidative stress, which promotes degradation of plant compounds and facilitates infection.ConclusionsThe present work reports six genomes and provides a database of the putative effectorome of Moniliophthora, a first step towards the understanding of the functional basis of fungal pathogenicity.Electronic supplementary materialThe online version of this article (10.1186/s12864-018-4875-7) contains supplementary material, which is available to authorized users.

Transcriptional regulation, led by transcription factors (TFs) such as those of the WRKY family, is a mechanism used by the organism to enhance or repress gene expression in response to stimuli. Here, we report on the genome-wide analysis of the Theobroma cacao WRKY TF family and also investigate the expression of WRKY genes in cacao infected by the fungus Moniliophthora perniciosa. In the cacao genome, 61 non-redundant WRKY sequences were found and classified in three groups (I to III) according to the WRKY and zinc-finger motif types. The 61 putative WRKY sequences were distributed on the 10 cacao chromosomes and 24 of them came from duplication events. The sequences were phylogenetically organized according to the general WRKY groups. The phylogenetic analysis revealed that subgroups IIa and IIb are sister groups and share a common ancestor, as well as subgroups IId and IIe. The most divergent groups according to the plant origin were IIc and III. According to the phylogenetic analysis, 7 TcWRKY genes were selected and analyzed by RT-qPCR in susceptible and resistant cacao plants infected (or not) with M. perniciosa. Some TcWRKY genes presented interesting responses to M. perniciosa such as Tc01_p014750/Tc06_p013130/AtWRKY28, Tc09_p001530/Tc06_p004420/AtWRKY40, Tc04_p016130/AtWRKY54 and Tc10_p016570/ AtWRKY70. Our results can help to select appropriate candidate genes for further characterization in cacao or in other Theobroma species.

-In the northeastern region of Brazil, saline soils are constraints to banana production, becoming necessary to understand the mechanisms of salt tolerance. two bananas genotypes, tap Maeo, tolerant, and Berlin, sensitive, were subjected to treatment with 50 mol m -3 Nacl or without salt. this study evaluated the effects of salt on the following physiological aspects: leaf area, content and distribution of Na + , membrane integrity, proton atPase activity. Besides, a search for differentially expressed genes was performed using the Differential Display technique. tap Maeo genotype showed the smallest reduction in leaf area, smaller accumulation of Na + and malondialdehyde (MDa), and higher activity of proton atPase activity. two sequences differentially expressed in the tolerant genotype, (Musa 07, Musa 23), shared a high degree of identity with the amino acid sequences of the genes SOS1 and SOS2, respectively. the clone Musa 10 was highly similar to amino acid sequence of the ascorbate peroxidase gene, and Musa 26, encodes the enzyme betaine aldehyde dehydrogenase. These significant biological markers indicate that salinity tolerance in banana involves at least two simultaneous mechanisms: the activation of the SOS pathway, increasing the extrusion of Na + , and the activation of antioxidative system, increasing the synthesis of aPX and betaine aldehyde dehydrogenase enzyme. Index terms: DDRt-PcR, leaf area, Musa, Na + , antioxidative system, SOS pathway. MECANISMOS DE TOLERÂNCIA À SALINIDADE EM BANANEIRA : ASPECTOS FISIOLÓGICOS, BIOQUÍMICOS E MOLECULARESRESUMO -Na região Nordeste do Brasil, solos salinos são restritivos à produção de banana, tornandose necessário compreender os mecanismos de tolerância de sal. Dois genótipos de banana, tap Maeo, tolerante, e Berlim, sensível, foram submetidos ao tratamento com 50 mol m-3 Nacl ou sem sal. este estudo avaliou os efeitos do sal sobre os seguintes aspectos fisiológicos: área foliar, conteúdo e distribuição de Na + , integridade da membrana, atividade da atPase. além disso, uma busca por genes diferencialmente expressos foi realizada usando a técnica Differential Display. O genótipo tap Maeo apresentou a menor redução na área foliar, menor acúmulo de Na + e malondialdeído (MDa) bem como maior atividade da H + atPase. Duas sequências diferencialmente expressas no genótipo tolerante (Musa 07, Musa 23) compartilham alto grau de identidade com as sequências de aminoácidos dos genes SOS1 e SOS2, respectivamente. O clone Musa 10 é muito semelhante à sequência de aminoácidos do gene da peroxidase do ascorbato, e o Musa 26 codifica a enzima aldeído betaína desidrogenase. Estes marcadores biológicos significativos indicam que a tolerância à salinidade em banana envolve pelo menos dois mecanismos simultâneos: a ativação da via SOS, aumentando a extrusão do Na + , e a ativação do sistema antioxidante, aumentando a síntese de aPX e da enzima aldeído betaína desidrogenase. Termos para indexação: área foliar, DDRt PcR, Musa, Na + , rota SOS, sistema antioxidativo. 1 (Pa...

Two new species and one new nothospecies of Tacinga from semi-arid Eastern Brazil are described. The new taxa were discovered on the basis of material collected during field trips carried out by staff of the Cactarium Guimarães Duque of the Instituto Nacional do Semiárido. A morphologic comparison of all the Tacinga species currently known, together with the cytogenetic analysis of the new taxa, are made. Full descriptions, illustrations, taxonomic discussions for all three new taxa are given as well as an identification key for all known Tacinga species. IUCN categories for the new taxa were assessed, resulting as endangered or critically endangered, due to their small population size and restricted distribution.

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