The coconut palm (Cocos nucifera L.) is a common crop in pantropical areas facing various challenges, one of them being the control of diseases and pests. Diseases such as bud rot caused by Phytophthora palmivora, lethal yellowing caused by phytoplasmas of the types 16SrIV-A, 16SrIV-D or 16SrIV-E, among others, and pests like the coconut palm weevil, Rhynchophorus vulneratus (Coleoptera: Curculionidae), and the horned beetle, Oryctes rhinocerus (Coleoptera: Scarabaeidae), are controlled by applying pesticides, pheromones and cultural control. These practices do not guarantee eradication since some causal agents have become resistant or are imbedded in infected tissues making them difficult to eradicate. This review condenses the current genomics, transcriptomics, proteomics and metabolomics studies which are being conducted with the aim of understanding the pathosystems associated with the coconut palm, highlighting the findings generated by omics studies that may become future targets for the control of diseases and pests in the coconut crop.

Cocos nucifera L. is one of the most cultivated palm trees in the world since it is used to obtain both raw materials and food. From a human point of view, the coconut fruit is a very valuable product, producing an aromatic and tasty liquid endosperm (coconut water) containing high levels of sugars, amino acids and other molecules of nutritional and nutraceutical value. Most of the chemical composition studies conducted on coconut to date have focused on the determination of fatty acid content in coconut oil and the extension of the shelf life of coconut water. Despite the economic importance of this species, the maturation of the coconut fruit is a complex biological process scarcely studied from the metabolic approach and biochemical changes occurring during fruit maturation are not well-known. The objective of this study is to investigate and elucidate the metabolic changes that occur during the maturation process of coconut (Cocos nucifera L.) fruits, specifically focusing on the liquid endosperm of the Yucatan green dwarf variety. In this study, the liquid endosperm of coconut fruits at the immature, intermediate and mature stages have been analyzed through an untargeted metabolomics approach by ultra performance liquid chromatography coupled to high resolution mass spectrometry (UPLC-HRMS). A total of 591 spectrometric features were detected and the corresponding identified compounds were classified into 24 chemical classes. The principal component analysis (PCA) showed segregation among the samples, according to their stage of maturation. Most of the metabolites detected were related to the metabolism of flavonoids, carbohydrates and organooxygen compounds. Pathway analysis showed that sphingolipid, starch and sucrose metabolisms were among the most over-accumulated during ripening, followed by the metabolism of glyoxylates and dicarboxylates and the metabolism of amino acids such as alanine, aspartate and glutamate, and others. This is the first study that focuses on elucidating the metabolic profiles of the liquid endosperm of coconut Yucatan green dwarf variety during three stages of maturation with an untargeted metabolomics approach through UPLC-MS.

Cocos nucifera L. is a crop grown in the humid tropics. It is grouped into two classes of varieties: dwarf and tall; regardless of the variety, the endosperm of the coconut accumulates carbohydrates in the early stages of maturation and fatty acids in the later stages, although the biochemical factors that determine such behavior remain unknown. We used tandem mass tagging with synchronous precursor selection (TMT-SPS-MS3) to analyze the proteomes of solid endosperms from Yucatan green dwarf (YGD) and Mexican pacific tall (MPT) coconut cultivars. The analysis was conducted at immature, intermediate, and mature development stages to better understand the regulation of carbohydrate and lipid metabolisms. Proteomic analyses showed 244 proteins in YGD and 347 in MPT; from these, 155 proteins were shared between both cultivars. Furthermore, the proteomes related to glycolysis, photosynthesis, and gluconeogenesis, and those associated with the biosynthesis and elongation of fatty acids, were up-accumulated in the solid endosperm of MPT, while in YGD, they were down-accumulated. These results support that carbohydrate and fatty acid metabolisms differ among the developmental stages of the solid endosperm and between the dwarf and tall cultivars. This is the first proteomics study comparing different stages of maturity in two contrasting coconut cultivars and may help in understanding the maturity process in other palms.

Background: Biofortification is the process by which the nutritional quality of food crops is improved through agronomic practices, conventional plant breeding, or modern biotechnology. The objective in this work was to determine the effect of iron on mineral content, proximal composition, bioactive compound content and antioxidant activity in the bean grain. Methods: In this present work, we biofortificated plants of common bean (Phaseolus vulgaris L.), with doses of iron sulfate (0, 0.25, and 0.50 g) and foliar iron chelate (0, 25, 50 and 100 µM). In the grain content mineral (iron, zinc, copper and nickel), proximal composition (moisture, ash, crude fiber, fat, protein, carbohydrates and energy), total phenols, flavonoids, anthocyanins and antioxidant activity were determined. Result: Edaphic and foliar biofortification increased iron content in the grain. All treatment combinations containing some edaphic or foliar doses of iron increased levels of ash fat, protein, crude fiber, total phenols and anthocyanins, and decreased carbohydrate content and energy. Nine treatment combinations, including the control, possessed the highest antioxidant activities (84.96-89.76%).

There is a limited number of studies analyzing the molecular and biochemical processes regulating the metabolism of the maturation of Cocos nucifera L. zygotic embryos. Our research focused on the regulation of carbohydrate and lipid metabolic pathways occurring at three developmental stages of embryos from the Mexican Pacific tall (MPT) and the Yucatan green dwarf (YGD) cultivars. We used the TMT-synchronous precursor selection (SPS)-MS3 strategy to analyze the dynamics of proteomes from both embryos; 1044 and 540 proteins were determined for the MPT and YGD, respectively. A comparison of the differentially accumulated proteins (DAPs) revealed that the biological processes (BP) enriched in the MPT embryo included the glyoxylate and dicarboxylate metabolism along with fatty acid degradation, while in YGD, the nitrogen metabolism and pentose phosphate pathway were the most enriched BPs. Findings suggest that the MPT embryos use fatty acids to sustain a higher glycolytic/gluconeogenic metabolism than the YGD embryos. Moreover, the YGD proteome was enriched with proteins associated with biotic or abiotic stresses, e.g., peroxidase and catalase. The goal of this study was to highlight the differences in the regulation of carbohydrate and lipid metabolic pathways during the maturation of coconut YGD and MPT zygotic embryos.