This study reports on expression analysis associated with molecular systems biology of cacao-Moniliophthora perniciosa interaction. Gene expression data were obtained for two cacao genotypes (TSH1188, resistant; Catongo, susceptible) challenged or not with the fungus M. perniciosa and collected at three time points through disease. Using expression analysis, we identified 154 and 227 genes that are differentially expressed in TSH1188 and Catongo, respectively. The expression of some of these genes was confirmed by RT-qPCR. Physical protein-protein interaction (PPPI) networks of Arabidopsis thaliana orthologous proteins corresponding to resistant and susceptible interactions were obtained followed by cluster and gene ontology analyses. The integrated analysis of gene expression and systems biology allowed designing a general scheme of major mechanisms associated with witches' broom disease resistance/susceptibility. In this sense, the TSH1188 cultivar shows strong production of ROS and elicitors at the beginning of the interaction with M. perniciosa followed by resistance signal propagation and ROS detoxification. On the other hand, the Catongo genotype displays defense mechanisms that include the synthesis of some defense molecules but without success in regards to elimination of the fungus. This phase is followed by the activation of protein metabolism which is achieved with the production of proteasome associated with autophagy as a precursor mechanism of PCD. This work also identifies candidate genes for further functional studies and for genetic mapping and marker assisted selection.

ABSTRACT. Many cell functions are redundantly executed in cells, and the experimental approaches that analyze the group of proteins, whose expression is modified in a specific functional condition, enable the identification of the group of proteins that are expressed under stress conditions. The objective of the present study was the evaluation of the genetic expression induced by cadmium (Cd) in Genipa americana L. (Rubiaceae) plants cultivated in nutritive solution, in order to help further studies concerning its use as a plant phytoremediator of such a metallic element. Plants were exposed to increasing concentrations of Cd (0.5, 1, 2, 4, 8, and 16 mg/L), together with the control, in nutritive solution. After the application of the treatments, root tips were harvested for the construction of a cDNA library. Of the 165 expressed sequence tags (ESTs) generated with the construction of the cDNA library, 81 showed homology to genes deposited in the NCBI database, 67 did not show similarity to any available gene, and 17 ESTs ESTs of genes in G. americana exposed to cadmium demonstrated homology with unknown genes. Of the most abundant cDNAs, 16 ESTs were similar to sequences of metallothionein genes. The analysis of ESTs, obtained from the root of G. americana through the construction of a cDNA library, allowed the identification of genes probably associated with proteins and enzymes related to the defense mechanisms of plants when they undergo biotic and abiotic stresses.

The phylogenetic position of a new species of Anhellia (Myriangiales) was investigated by analysis of nucleotide sequences of ribosomal large subunit (LSU) and ITS regions. The new sequence was aligned with 28 sequences obtained from GenBank, including four species of Davidiellaceae (Capnodiales) used as outgroup. This study is the first attempt to resolve the placement of the genus Anhellia within Myriangiales. The genus Anhellia was strongly supported in Myriangiaceae by phylogenetic analyses. In addition, A. nectandrae sp. nov., collected on Nectandra rigida from a fragment of Atlantic forest in Brazil, is described, illustrated and a table with morphological features to all known Anhellia species is provided.

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ABSTRACT. Cacao (Theobroma cacao) is one of the most important tropical crops; however, production is threatened by numerous pathogens, including the hemibiotrophic fungus Moniliophthora perniciosa, which causes witches' broom disease. To understand the mechanisms that lead to the development of this disease in cacao, we focused our attention on cacao transcription factors (TFs), which act as master regulators of cellular processes and are important for the finetuning of plant defense responses. We developed a macroarray with 88 TF cDNA from previously obtained cacao-M. perniciosa interaction libraries. Seventy-two TFs were found differentially expressed between the susceptible (Catongo) and resistant (TSH1188) genotypes and/or during the disease time course -from 24 h to 30 days after infection. Most of the differentially expressed TFs belonged to the bZIP, MYB and WRKY families and presented opposite expression patterns in susceptible and resistant cacao-M. perniciosa interactions (i.e., upregulated in Catongo and down-regulated in TSH1188). The results of the macroarray were confirmed for bZIP and WRKY TFs by realtime PCR. These differentially expressed TFs are good candidates for subsequent functional analysis as well as for plant engineering. Some of these TFs could also be localized on the cacao reference map related to witches' broom resistance, facilitating the breeding and selection of resistant cacao trees.