Biodiversity Studies in Key Species from the African Mopane and Miombo Woodlands

The Southern African Miombo-Mopane woodlands are globally considered as ecosystems with irreplaceable species endemism, being the most important type of vegetation in the region. Among the approximately 8500 plant species, legume trees play a crucial role in biodiversity dynamics, being also key socioeconomic and environmental players. From the ecological point of view, they contribute significantly to ecosystem’s stability as well as to water, carbon, and energy balance. Additionally, legume species represent an immensurable source of timber and nontimber products. Research in Miombo-Mopane biodiversity has been mainly focused on the analysis of ecosystem drivers by means of ecological parameters and models, lacking interdisciplinary with relevant cross-cutting tools, such as the application of molecular markers to assess genetic diversity within the region. In this chapter, the applications and biodiversity dynamics of typical legume species from Miombo (Brachystegia spp., Julbernardia globiflora, and Pterocarpus angolensis) and Mopane (Colophospermum mopane) are reviewed. Gaps and challenges are also brought forward in the context of the lack of genetic diversity assessments and the need of an effective and coordinated network of interdisciplinary research

Characterization of the primary matabolome of Brachystegia boehmii and Colophospermum mopane under different fire regimes in Miombo and Mopane African woodlands

Original ResearchMiombo and Mopane are ecological and economic important woodlands from Africa, highly affected by a combination of climate change factors, and anthropogenic fires. Although most species of these ecosystems are fire tolerant, the mechanisms that lead to adaptive responses (metabolic reconfiguration) are unknown. In this context, the aim of this study was to characterize the primary metabolite composition of typical legume trees from these ecosystems, namely, Brachystegia boehmii (Miombo) and Colophospermum mopane (Mopane) subjected to different fire regimes. Fresh leaves from each species were collected in management units and landscapes across varied fire frequencies in the Niassa National Reserve (NNR) and Limpopo National Park (LNP) in Mozambique. Primary metabolites were extracted and analyzed with a well-established gas chromatography time-of-flight mass spectrometry metabolomics platform (GC-TOF-MS). In B. boehmii, 39 primary metabolites were identified from which seven amino acids, two organic acids and two sugars increased significantly, whereas in C. mopane, 41 primary metabolites were identified from which eight amino acids, one sugar and two organic acids significantly increased with increasing fire frequency. The observed changes in the pool of metabolites of C. mopane might be related to high glycolytic and tricarboxylic acid (TCA) rate, which provided increased levels of amino acids and energy yield. In B. boehmii, the high levels of amino acids might be due to inhibition of protein biosynthesis. The osmoprotectant and reactive oxygen species (ROS) scavenging properties of accumulated metabolites in parallel with a high-energy yield might support plants survival under fire stressinfo:eu-repo/semantics/publishedVersio

Linking Bacterial Rhizosphere Communities of Two Pioneer Species, Brachystegia boehmii and B. spiciformis, to the Ecological Processes of Miombo Woodlands

Miombo is the most extensive ecosystem in southern Africa, being strongly driven by fire, climate, herbivory, and human activity. Soils are major regulating and supporting services, sequestering nearly 50% of the overall carbon and comprising a set of yet unexploited functions. In this study, we used next-generation Illumina sequencing to assess the patterns of bacterial soil diversity in two pioneer Miombo species, Brachystegia boehmii and Brachystegia spiciformis, along a fire gradient, in ferric lixisol and cambic arenosol soils. In total, 21 phyla, 51 classes, 98 orders, 193 families, and 520 genera were found, revealing a considerably high and multifunctional diversity with a strong potential for the production of bioactive compounds and nutrient mobilization. Four abundant genera characterized the core microbiome among plant species, type of soils, or fire regime: Streptomyces, Gaiella, Chthoniobacter, and Bacillus. Nevertheless, bacterial networks revealed a higher potential for mutualistic interactions and transmission of chemical signals among phylotypes from low fire frequency sites than those from high fire frequency sites. Ecological networks also revealed the negative effects of frequent fires on the complexity of microbial communities. Functional predictions revealed the core “house-keeping” metabolisms contributing to the high bacterial diversity found, suggesting its importance to the functionality of this ecosystem.info:eu-repo/semantics/publishedVersio

Genomic evaluation of Coffea arabica and its wild relative Coffea racemosa in Mozambique: settling resilience keys for the Coffee crop in the context of climate change

Climate change is negatively affecting the coffee value chain, with a direct effect on approximately 100 million people from 80 countries. This has been attributed to the high vulnerability of the two-mainstream species, Coffea arabica and Coffea canephora, to extreme weather events, with notable uneven increases in market prices. Taking into account the narrow genetic plasticity of the commercial coffee cultivars, wild-relatives and underutilized Coffea species are valuable genetic resources. In this work, we have assessed the occurrence of Coffea species in to understand the degree of genetic relationships between Coffea species in the country, as well as the patterns of genetic diversity, differentiation, and genetic structure. Only one wild species was found, C. racemosa, which showed a high level of genetic separation with C. arabica, based on plastid, as well as SSR and SNP analysis. C. arabica presented low levels of diversity likely related to their autogamous nature, while the allogamous C. racemosa presented higher levels of diversity and heterozygosity. The analysis of the functional pathways based on SNPs suggests that the stress signaling pathways are more robust in this species. This novel approach shows that it is vital to introduce more resilient species and increase genomic diversity in climate-smart practices.This researchwas funded by by Camões, Instituto da Cooperação e da Língua (CICL), Agência Brasileira de Cooperação (ABC), and ParqueNacional da Gorongosa (PNG), under the Triangular Project TriCafé (GorongosaCoffee), and by Fundação para a Ciência e a Tecnologia, I.P. (FCT)info:eu-repo/semantics/publishedVersio

Applications of Essential Oils as Antibacterial Agents in Minimally Processed Fruits and Vegetables - A Review

Microbial foodborne diseases are a major health concern. In this regard, one of the major risk factors is related to consumer preferences for “ready-to-eat” or minimally processed (MP) fruits and vegetables. Essential oil (EO) is a viable alternative used to reduce pathogenic bacteria and increase the shelf-life of MP foods, due to the health risks associated with food chlorine. Indeed, there has been increased interest in using EO in fresh produce. However, more information about EO applications in MP foods is necessary. For instance, although in vitro tests have defined EO as a valuable antimicrobial agent, its practical use in MP foods can be hampered by unrealistic concentrations, as most studies focus on growth reductions instead of bactericidal activity, which, in the case of MP foods, is of utmost importance. The present review focuses on the effects of EO in MP food pathogens, including the more realistic applications. Overall, due to this type of information, EO could be better regarded as an added value to the food industryinfo:eu-repo/semantics/publishedVersio

potential for soil health improvement anwd plant growth promotion

Funding text: This work was supported by funds from Camões, Instituto da Cooperação e da Língua and Fundação para a Ciência e a Tecnologia through the research unit UIDB/00239/2020 (CEF), the PhD grant SFRH/BD/113951/2015 (Ivete Sandra Maquia), and the contribution to the International Rice Research Institute.(1) Aims: Assessing bacterial diversity and plant-growth-promoting functions in the rhizosphere of the native African trees Colophospermum mopane and Combretum apiculatum in three landscapes of the Limpopo National Park (Mozambique), subjected to two fire regimes. (2) Methods: Bacterial communities were identified through Illumina Miseq sequencing of the 16S rRNA gene amplicons, followed by culture dependent methods to isolate plant growth-promoting bacteria (PGPB). Plant growth-promoting traits of the cultivable bacterial fraction were further analyzed. To screen for the presence of nitrogen-fixing bacteria, the promiscuous tropical legume Vigna unguiculata was used as a trap host. The taxonomy of all purified isolates was genetically verified by 16S rRNA gene Sanger sequencing. (3) Results: Bacterial community results indicated that fire did not drive major changes in bacterial abundance. However, culture-dependent methods allowed the differentiation of bacterial communities between the sampled sites, which were particularly enriched in Proteobacteria with a wide range of plant-beneficial traits, such as plant protection, plant nutrition, and plant growth. Bradyrhizobium was the most frequent symbiotic bacteria trapped in cowpea nodules coexisting with other endophytic bacteria. (4) Conclusion: Although the global analysis did not show significant differences between landscapes or sites with different fire regimes, probably due to the fast recovery of bacterial communities, the isolation of PGPB suggests that the rhizosphere bacteria are driven by the plant species, soil type, and fire regime, and are potentially associated with a wide range of agricultural, environmental, and industrial applications. Thus, the rhizosphere of African savannah ecosystems seems to be an untapped source of bacterial species and strains that should be further exploited for bio-based solutions.publishersversionpublishe

Fire and biodiversity dynamics of two priority legume tree species from Miombo (Brachystegia boehmii Taub.) and MOPANE (Colophosperum mopane (J. Kirk ex Benth) J. Léonard) Woodlands in Mozambique

Forest tree genetic resources are one of the most important repositories of biological diversity, constituting a key component for the stability of the ecosystems. Due to the increasing human pressure and global climate changes, the management and conservation of forests has become a key issue in order to sustain their productive, environmental and socio-economic value. Therefore, worldwide the development of appropriated conservation strategies became a priority and several international, regional and national initiatives and framework instruments have been established. The research focused on the analysis of plant and microbial diversity in the Miombo and Mopane woodlands, the densely-forested ecosystems of African savannas, in two key conservation areas, the Niassa Special Reserve (NSR), northern Mozambique, and Limpopo National Park (LNP), southern of Mozambique, respectively. Both ecosystems are considered sources of woody species, their resources contributing to the livelihood systems of millions of households in rural and urban areas that depend on these ecosystems for their food, health, energy and housing needs. Moreover, these ecosystems play an important role for the environment, for its overall impact on energy, water and carbon balance. Fire is the major threat to which these ecosystems are exposed, being essentially related to human and climate pressure and herbivory by elephants. The project aimed at contributing to the Management Program of NSR and LNP, particularly to the components of fire control and biodiversity conservation. The proposed work was integrated into a multi-disciplinary program and focused on two selected priority species from the legume family, Brachystegia boehmii (Miombo) and Colophospherum mopane (Mopane), preceeded by an overall characterization of legume tree distribution, diversity and conservation status in the two ecosystems. In the first part of the study it was concluded that, despite the high diversity of species (78), there was a notable research gap regarding their conservation status (Chapter 2). Over the last two years, this gap has been properly addressed and the percentage of catalogued species in the International Union for Conservation of Nature’s Red List of Threatened Species – IUCN, has increased from 15 to 77%. Most of the species (56) are classified as least concern, 2 as vulnerable, and another 2 as nearly threatened, reflecting the ongoing conservation efforts in the region. The remaining 18, in which the two focal species of this thesis are included, were not yet evaluated (Chapter 5). In the second part of the the work (Chapters 3 and 4), the dynamics of rhizobacteria diversity and associated functional traits have been analysed, considering different soil types and fire regimes, using culture-independent (Metagenomics) and culture dependent approaches. Despite the fact that both Miombo and Mopane rhizosphere bacteria were quite rich, there was a clear difference between them. First, the abundance of Operational Taxonomic Units (OTUs) was higher in B. boehmii (977 – 1391 OTUs) than in C. mopane (696 – 831 OTUs), which was also reflected in the Shannon diversity index, i.e. 7.21 – 8.50 vs 4.040 – 4.087, respectively. Second, while the bacterial diversity in the rhizosphere of B. boehmii varied with the soil type and fire frequency, no changes were observed in C. mopane. This may be attributed to the multi-specific nature of Miombo vs. the mono-specific nature of Mopane. However, in both cases, a pyrodiversity effect seems to be an important evolutionary driver towards high-temperature tolerance in both cases. The most representative groups were Actinobacteria (40%), Proteobacteria (20%), and Acidobacteria (13%) in Miombo and Firmicutes (31%), Bacteroidetes (25%), and Proteobacteria (23%). At the species level, the rhizosphere of B. boehmii was enriched in newly characterized species from recalcitrant environments, like the thermophilic, halo- and radiotolerant Gaiella oculta and the thermotolerant Rhodoplanes tepidicaeni and Saccharopolyspora spongiae, likely playing multiple roles in plant growth and protection as well as in soil fertility and/or restauration and/or remediation. The metagenomics approach did not allow to resolve taxonomic questions at the species level in the Mopane rhizosphere, probably because the most abundant species are yet unidentified. However, higher taxonomic classification suggests that the diversity of functions accomplished by these bacteria is similar to that of Miombo. Regarding the Plant Growth-Promoting Bacteria (PGPB) isolated from soils, a larger collection was captured in Mopane (16 isolates, nine species: Bacillus sp., Caballeronia concitans, Pantoea agglomerans, Paraburkholderia phenoliruptrix, Phyllobacterium myrsinacearum, Pseudomonas azotoformans, Pseudomonas gessardii, Pseudomonas synxantha and Stenotrophomonas maltophilia) than in Miombo (eight isolates, five species: Burkholderia sp., Caballeronia zhejiangensis, Microvirga sp., Rhizobium spp., Variovorax defluvii), all accomplishing at least one PGP trait, i.e. nitrogen fixation, phosphate solubilization, indole acetic acid production, siderophore production, and hydrolysis of cellulose. Regarding the bacteria trapped in Vigna unguiculata (cowpea) nodules, the number of isolates was considerably higher in Miombo (64 isolates, including symbiotic Ensifer adhaerens, Mesorhizobium sp., Neorhizobium galegae, Rhizobium sp., and non-symbiotic Agrobacterium sp., Cohnella sp., Herbaspirillum huttiense, Pseudomonas sp., and Stenotrophomonas sp.) than in Mopane (23 isolates, including symbiotic Bradyrhizobium sp. and Rhizobium sp., and non-symbiotic Azospirillum zeae, Cohnella rhizosphaerae, P. agglomerans, Pseudomonas nitroreducens. In both cases, nodule consortia bacteria promoted cowpea growth, but the effect of Miombo consortia was considerably more prominent. Altogether the results revealed that rhizospere bacteria from both Miombo and Mopane are highly resilient to soil composition and fire, hiddding an enourmous bio-economic potential for the devolpement of nature-based solutions like, the production of fertilizers, soil remediators, phytostimulators, or antimicrobials. The produced knowledge constitutes a significant contribution to the understanding of the dynamics of soil bacteria in tropical forest ecosystems, namely in what concerns plant-microbe interactions, and bioprospection of new species. Despite the fact that tropical ecosystems host ca. 80% of the global biodiversity, pressures imposed by a combination of human, animal and climate pressure are imposing major challenges. Thus, understanding key aspects of the ecosystem dynamics is of utmost importance to support community-based conservation programs