Overexpression of Water-Responsive Genes Promoted by Elevated CO2 Reduces ROS and Enhances Drought Tolerance in Coffea Species.

Drought is a major constraint to plant growth and productivity worldwide and will aggravate as water availability becomes scarcer. Although elevated air [CO2] might mitigate some of these effects in plants, the mechanisms underlying the involved responses are poorly understood in woody economically important crops such as Coffea. This study analyzed transcriptome changes in Coffea canephora cv. CL153 and C. arabica cv. Icatu exposed to moderate (MWD) or severe water deficits (SWD) and grown under ambient (aCO2) or elevated (eCO2) air [CO2]. We found that changes in expression levels and regulatory pathways were barely affected by MWD, while the SWD condition led to a down-regulation of most differentially expressed genes (DEGs). eCO2 attenuated the impacts of drought in the transcripts of both genotypes but mostly in Icatu, in agreement with physiological and metabolic studies. A predominance of protective and reactive oxygen species (ROS)-scavenging-related genes, directly or indirectly associated with ABA signaling pathways, was found in Coffea responses, including genes involved in water deprivation and desiccation, such as protein phosphatases in Icatu, and aspartic proteases and dehydrins in CL153, whose expression was validated by qRT-PCR. The existence of a complex post-transcriptional regulatory mechanism appears to occur in Coffea explaining some apparent discrepancies between transcriptomic, proteomic, and physiological data in these genotypes.

Biochemical and Molecular Profiling of Wild Edible Mushrooms from Huila, Angola.

The harvesting, processing, and sale of wild edible mushrooms (WEM) is a relevant economic activity in Angola and a good example of the use of non-wood forest products for food. Although there is deep traditional knowledge about the general properties of WEMs, a huge gap remains in detailed scientific knowledge. Thus, this study aimed to investigate the socio-economic importance of the species sold at local markets in Huila, Angola, from their molecular identification to the assessment of their nutritional, chemical, and bioactive profiles. From the eight WEM morphotypes studied, five were identified based on phenotypical and molecular approaches (four Russula spp., and Amanita loosei). The studied mushrooms proved to be a rich source of carbohydrates, proteins, and ashes, also presenting low amounts of fat. Chemical analyses further revealed mannitol as the main free sugar in all samples, and organic acids, namely, oxalic, quinic, malic, citric, and fumaric acids in low amounts. Additionally, the α-tocopherol isoform and monounsaturated fatty acids were predominant. Regarding phenolic acids, protocatechuic, p-hydroxybenzoic, p-coumaric, and cinnamic acids were detected in all mushroom hydroethanolic extracts, being responsible for their antioxidant, antibacterial, and antifungal activities. Our investigation contributes to the identification and knowledge of WEMs as important complementary food sources in Angola, some of which were reported for the first time, promoting their utilization as a basis of nutritional and functional ingredients, as being able to be part of a balanced diet and to be used in new bio-based formulations.

First Report of Dieback Caused by Neofusicoccum batangarum in Cashew in Guinea-Bissau.

Cashew (Anacardium occidentale L.) is a cash crop with a highly significant economic importance in West Africa, particularly in Guinea-Bissau (Monteiro et al. 2015, 2017). In October 2018, dieback-like symptoms such as wilt and necrosis of apical shoots were observed in 10 % of the cashew trees grown in a 100 plant-orchard in Bolama Island at Bijagós archipelago, Guinea-Bissau. Six symptomatic apical shoots from individual plants were collected for fungal isolation and identification. Tissue pieces (3 × 2 mm) from healthy to diseased margins were surface sterilized with 1 % sodium hypochlorite, washed twice with sterilized water, placed on potato dextrose agar (PDA, Difco® Laboratories) supplemented with potassium thiocyanate (50 µg/ml), and incubated at 24 ± 1 °C in the dark for 7 days. Four fungal colonies were isolated (67 %) and purified through hyphal tips removal, displaying rapid growth rate, and aerial mycelia that initially was white, turning later to dark greenish on PDA. Pycnidia produced on 1.5 % water agar and sterilized pine needles (± 25ºC; near-UV light) were solitary, covered by mycelium, obpyriform to ampulliform (152.5 ± 41.6 × 135.2 ± 30.8 µm, n = 30). Conidia were unicellular, hyaline, smooth, fusoid to ovoid, thin-walled, measuring 16.21 ± 1.52 × 5.84 ± 0.66 µm (n = 50, L/W 2.8). Such morphological features are characteristic of Neofusicoccum spp. (Phillips et al. 2013). For molecular identification, genomic DNA was extracted from a representative isolate GB160 and partial regions of ribosomal internal transcriber spacer (ITS) (ITS1/ITS4; White et al. 1990), translation elongation factor 1-α (EF1-α) (EF1-688F/EF1-1251R; Alves et al. 2008) and ß-tubulin (ß-tub) (Bt2a/Bt2b; Glass and Donaldson 1995) genes were amplified as previously described, respectively, with BSA (50 mg/ml). Amplicons were sequenced and deposited in GenBank (ITS, MN952993; EF1-α, MN952204; ß-tub, MN952208). BLAST analysis of ITS, EF1-α and ß-tub gene sequences showed 100 % identity with Neofusicoccum batangarum reference strain CBS124923 (FJ900608, FJ900654, FJ900635, respectively). Maximum-likelihood and Bayesian Inference analyses from the concatenated dataset placed GB160 isolate within the N. batangarum cluster (BS = 72 %; PP = 0.95). For pathogenicity assessment, 3-month-old cashew "Caju di Terra" plants (n = 8) grown in a greenhouse under controlled conditions were inoculated following a randomized block design as described by Lima et al. (2013). Briefly, 3 mm diam. stem tissue bark was removed and replaced with a 3 mm diameter PDA plug retrieved from the colony margin. Inoculation wound was covered with sterilized wet cotton and sealed with parafilm. Eight control plants were only treated with PDA plugs and the wound covered and sealed as described. After 15 days, all inoculated plants displayed similar symptoms to those observed in the field, and vascular lesions (10.8 ± 4.0 cm), whereas control plants remained symptomless. Koch's postulates were fulfilled by successful re-isolation of the pathogen from all inoculated stems and identification by morphology and gene sequencing. N. batangarum was identified associated with Anacardium spp. in Brazil (Netto et al. 2017) and recently reported as causing grapevine dieback in Brazil (Rêgo et al. 2020). To our knowledge, this is the first report of N. batangarum causing cashew dieback in Guinea-Bissau and West Africa. Occurrence of this disease may represent a significant impact for cashew production since this crop is the major agricultural commodity in Guinea-Bissau.

Population genomic footprints of host adaptation, introgression and recombination in coffee leaf rust.

Coffee leaf rust, caused by Hemileia vastatrix (Hv), represents the biggest threat to coffee production worldwide and ranks amongst the most serious fungal diseases in history. Despite a recent series of outbreaks and emergence of hypervirulent strains, the population evolutionary history and potential of this pathogen remain poorly understood. To address this issue, we used restriction site-associated DNA sequencing (RADseq) to generate ∼19 000 single nucleotide polymorphisms (SNPs) across a worldwide collection of 37 Hv samples. Contrary to the long-standing idea that Hv represents a genetically unstructured and cosmopolitan species, our results reveal the existence of a cryptic species complex with marked host tropism. Using phylogenetic and pathological data, we show that one of these lineages (C3) infects almost exclusively the most economically valuable coffee species (tetraploids that include Coffea arabica and interspecific hybrids), whereas the other lineages (C1 and C2) are severely maladapted to these hosts, but successfully infect diploid coffee species. Population dynamic analyses suggest that the C3 group may be a recent 'domesticated' lineage that emerged via host shift from diploid coffee hosts. We also found evidence of recombination occurring within this group, which could explain the high pace of pathotype emergence despite the low genetic variation. Moreover, genomic footprints of introgression between the C3 and C2 groups were discovered and raise the possibility that virulence factors may be quickly exchanged between groups with different pathogenic abilities. This work advances our understanding of the evolutionary strategies used by plant pathogens in agro-ecosystems with direct and far-reaching implications for disease control.

A first insight into the involvement of phytohormones pathways in coffee resistance and susceptibility to Colletotrichum kahawae.

Understanding the molecular mechanisms underlying coffee-pathogen interactions are of key importance to aid disease resistance breeding efforts. In this work the expression of genes involved in salicylic acid (SA), jasmonic acid (JA) and ethylene (ET) pathways were studied in hypocotyls of two coffee varieties challenged with the hemibiotrophic fungus Colletotrichum kahawae, the causal agent of Coffee Berry Disease. Based on a cytological analysis, key time-points of the infection process were selected and qPCR was used to evaluate the expression of phytohormones biosynthesis, reception and responsive-related genes. The resistance to C. kahawae was characterized by restricted fungal growth associated with early accumulation of phenolic compounds in the cell walls and cytoplasmic contents, and deployment of hypersensitive reaction. Similar responses were detected in the susceptible variety, but in a significantly lower percentage of infection sites and with no apparent effect on disease development. Gene expression analysis suggests a more relevant involvement of JA and ET phytohormones than SA in this pathosystem. An earlier and stronger activation of the JA pathway observed in the resistant variety, when compared with the susceptible one, seems to be responsible for the successful activation of defense responses and inhibition of fungal growth. For the ET pathway, the down or non-regulation of ET receptors in the resistant variety, together with a moderate expression of the responsive-related gene ERF1, indicates that this phytohormone may be related with other functions besides the resistance response. However, in the susceptible variety, the stronger activation of ERF1 gene at the beginning of the necrotrophic phase, suggests the involvement of ET in tissue senescence. As far as we know, this is the first attempt to unveil the role of phytohormones in coffee-C. kahawae interactions, thus contributing to deepen our understanding on the complex mechanisms of plant signaling and defense.

Chemical profiling of Portuguese Pinus pinea L. nuts.

BACKGROUND: The first detailed chemical characterisation of Portuguese pine nut (Pinus pinea L.) is reported concerning proximate composition, fatty acid, mineral and vitamin contents. RESULTS: Based on the analysis of 27 different populations, pine nuts were characterised by high contents of fat (47.7 g per 100 g dry matter (DM)), protein (33.8 g per 100 g DM) and phosphorus (1130 mg per 100 g DM) and low contents of moisture (5.9 g per 100 g DM) and starch (3.5 g per 100 g DM). They were also found to be a good source of zinc, iron and manganese. CONCLUSION: Mineral composition seemed to be most prone to variation, suggesting its potentially useful role in discriminating Mediterranean pine nuts. A significant variability was found in the nut composition of Portuguese P. pinea populations.