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Investigations of the compatibility between cacao genotypes of the population of the Parinari series (Pa), resulting from the reciprocal crossing of Pa 30 × Pa 169 and Pa 121 × Pa 169, allowed the verification of the occurrence of the recessive lethal single character called Luteus-Pa. These genotypes have this gene in heterozygosity, which when intercross or self-fertilize, segregate in a 3:1 ratio. Normal (NS) and mutant (MS) seedlings grow normally and, after a period of approximately 30 days of age, MS leaves begin to show a metallic yellow color, followed by necrotic spots, and death of the entire seedling, approximately 40 days after the emergency. The work evaluate the molecular, biochemical and micromorphological responses in NS and MS, with and without cotyledons, resulting from the crossing of the Pa 30 × Pa 169 cacao genotypes, aiming to elucidate the possible lethal mechanisms of the homozygous recessive Luteus-Pa. The presence of the lethal gene Luteus-Pa in the seedlings of the cacao genotypes of the population of the Parinari (Pa), with and without cotyledons, resulting from the crossing of Pa 30 × Pa 169, in addition to regulating the synthesis of proteins related to the photosynthetic and stress defense processes, promoted an increase in the synthesis of proteins involved in the glycolic pathway, induced oxidative stress, altered the mobilization of cotyledonary reserves, the integrity of cell membranes, leaf micromorphology and induced the death of seedlings, soon after depletion of protein and carbohydrate reserves, especially in the absence of cotyledons.

Cocoa is a perennial and arboreal species intolerant to strong and frequent winds and, for this reason, is usually grown with windbreaks of trees. The mechanical alterations caused by the wind in the field have a great impact on the growth, development and productivity of cocoa. The present work had a main objective to understand the molecular mechanisms of responses to mechanical stress, caused by the action of constant wind flow in young plants of cocoa through alterations of the proteomic profile in young (YL) and mature leaves (ML). Plants were exposed to constant wind (CW) at a speed of 4.5 m s−1 for 12 h. There was a reduction in the accumulation of proteins in YL and a significant increase in ML submitted to CW in relation to the control. Differentially accumulated proteins, identified in YL and ML, belong to a broad functional group, related to energy production and carbon metabolism. Besides that, there was a higher efficiency in the protein relative abundance associated to energy production and the assimilation of carbon in the ML exposed to CW, in relation to the control. It was observed the appearance of new isoforms and, or post-transitional changes, which represent an acclimatization and tolerance response of these leaves to the stressor factor. In contrast, in YL, the energy production and the synthesis of gene products essential for their growth and development were affected by the mechanical stress caused by the wind, making them more intolerant.

Diseases associated with Phytophthora cause considerable losses in cocoa production worldwide. Analyzing genes, proteins, and metabolites involved in Theobroma cacao’s interaction with Phytophthora species is essential to explaining the molecular aspects of plant defense. Through a systematic literature review, this study aims to identify reports of genes, proteins, metabolites, morphological characteristics, and molecular and physiological processes of T. cacao involved in its interaction with species of Phytophthora. After the searches, 35 papers were selected for the data extraction stage, according to pre-established inclusion and exclusion criteria. In these studies, 657 genes and 32 metabolites, among other elements (molecules and molecular processes), were found to be involved in the interaction. The integration of this information resulted in the following conclusions: the expression patterns of pattern recognition receptors (PRRs) and a possible gene-to-gene interaction participate in cocoa resistance to Phytophthora spp.; the expression pattern of genes that encode pathogenesis-related (PRs) proteins is different between resistant and susceptible genotypes; phenolic compounds play an important role in preformed defenses; and proline accumulation may be involved in cell wall integrity. Only one proteomics study of T. cacao-Phytophthora spp. was found, and some genes proposed via QTL analysis were confirmed in transcriptomic studies.

Significant scientific advances to elucidate the Moniliophthora perniciosa pathosystem have been achieved in recent years, but the molecular biology of this pathogen-host interaction is still a field with many unanswered questions. In order to present insights at the molecular level, we present the first systematic review on the theme. All told, 1118 studies were extracted from public databases. Of these, 109 were eligible for the review, based on the inclusion and exclusion criteria. The results indicated that understanding the transition from the biotrophic-necrotrophic phase of the fungus is crucial for control of the disease. Proteins with strong biotechnological potential or that can be targets for pathosystem intervention were identified, but studies regarding possible applications are still limited. The studies identified revealed important genes in the M. perniciosa-host interaction and efficient molecular markers in the search for genetic variability and sources of resistance, with Theobroma cacao being the most common host. An arsenal of effectors already identified and not explored in the pathosystem were highlighted. This systematic review contributes to the understanding of the pathosystem at the molecular level, offering new insights and proposing different paths for the development of new strategies to control witches’ broom disease.

Decreased accumulation of polyphenol oxidase, H2O2 accumulation, effective regulation of programmed cell death, and a protein predicted as allergenic can play key roles in cacao defense against Ceratocystis cacaofunesta. Ceratocystis wilt, caused by the fungus Ceratocystis cacaofunesta, has destroyed millions of Theobroma cacao trees in several countries of the Americas. Through proteomics, systems biology, and enzymatic analyses of infected stems, it was possible to infer mechanisms used by resistant (TSH1188) and susceptible (CCN51) cacao genotypes during infection. Protein extraction from xylem-enriched tissue of stems inoculated with the fungus and their controls 1 day after inoculation was carried out, followed by separation through two-dimensional gel electrophoresis and identification by mass spectrometry. Enzyme activity was determined at 1, 3, 7 and 15 days after inoculation. A total of 50 differentially accumulated distinct proteins were identified in the treatments of both genotypes and were classified into 10 different categories. An interaction network between homologous proteins from Arabidospsis thaliana was generated for each genotype, using the STRING database and Cytoscape software. Primary metabolism processes were apparently repressed in both genotypes. The resistance factors suggested for genotype TSH1188 were: H2O2 accumulation, effective regulation of programmed cell death, production of phytoalexins derived from tryptophan and furanocoumarins, and participation of a predicted allergenic protein with probable ribonuclease function inhibiting the germination and propagation of the fungus. In the susceptible genotype, it is possible that its recognition and signaling mechanism through proteins from the SEC14 family is easily overcome by the pathogen. Our results will help to better understand the interaction between cacao and one of its most aggressive pathogens, to create disease control strategies.

The aim of this study was to investigate the proteins found in tear film of healthy domestic cats. Schirmer tear test strips were used to collect tear samples of twelve healthy cats, which were mixed, centrifuged, and placed in a single 1.5 mL microtube that was frozen at −20°C, until analysis by two-dimensional polyacrylamide gel and mass spectrometry associated with high-performance liquid chromatography. The resulting spectra were analyzed and compared with the Swiss-Prot search tool. Forty peptides were detected in the analyzed protein fragments of 90 spots, with 16 proteins identified. Of these, the authors confirmed what has been already found in other studies: lactotransferrin, serum albumin, allergenic lipocalins, and neutrophil gelatinase-associated lipocalin. Others were considered novel in tear film samples of all species: cyclin-dependent protein kinase, serine/arginine repetitive matrix protein, apelin receptor, secretory protein related to C1q/TNF, Wee1, α-1,4 glucan phosphorylase, and WD repeat domain 1. The network was divided into 11 clusters, and a biological function was assigned. Most of the proteins have functions in the defense and maintenance of feline ocular surface homeostasis. Serum albumin is a bottleneck protein, with a high betweenness value. This paper is a pioneer in reporting, in-depth, the tear film proteome of domestic cats.