Research Articles (Plant Production and Soil Science)
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Item Taking stock of South Africa's flora(Elsevier, 2025-09) Le Roux, M. Marianne; Klopper, Ronell RenettSouth Africa is rich in plant biodiversity and has a longstanding history of record-keeping of its plant resources. In recent years, updated versions of the South African National Plant Checklist (Checklist) have been published annually in electronic form, reflecting changes from published taxonomic revisions and new species descriptions. The most recent Checklist from 2025 recognises 23 514 taxa and 21 539 species (20 204 indigenous and 1 329 naturalised species). Of the indigenous species, 60.5 % are endemic to the country. The e-Flora of South Africa project (e-Flora) was initiated in 2013 and the first phase was completed in 2020. Both the Checklist and e-Flora data were published online in 2024 on the South African National Biodiversity Institute’s Biodiversity Advisor website. The e-Flora adds a layer of descriptive information to the list of names provided in the Checklist, thereby enhancing the utility of these outputs for end-users from a variety of biodiversity-related fields. The e-Flora is a dynamic data source with updates guided by changes incorporated in the Checklist. An overview of the statistics from both the Checklist and the e-Flora, as of March 2025, are provided. HIGHLIGHTS • The South African National Plant Checklist recognises 21,539 species. • Species endemism is recorded at 60.5 %. • KwaZulu-Natal hosts the most number of families and genera while the Western Cape is most speciose. • The e-Flora of South Africa holds descriptions for 22,056 taxa. • Checklist and e-Flora data are accessible on the SANBI Biodiversity Advisor.Item Leaf anatomical traits of macadamia cultivars with potential links to drought tolerance(Elsevier, 2025-05) Maumela, Khodani; Taylor, Nicolette Jane; Oberlander, Kenneth Carl; Kritzinger, Angelique; angelique.kritzinger@up.ac.zaSelecting Macadamia cultivars with anatomical traits capable of withstanding drought may improve water management in their cultivation. Macadamia integrifolia, Macadamia tetraphylla, and their hybrids are commercially grown in South Africa for their high-value edible nuts, however, to improve yields, irrigation is required. This study examined leaf and petiole anatomical traits linked with plant water-use strategies in four commonly planted cultivars: ‘695′, ‘814′, ‘816′, and ‘A4’. Key traits investigated included stomatal density, mesophyll thickness (palisade and spongy parenchyma), vein density, and petiole Huber value. Fully matured macadamia leaves with their petioles were collected from Komatipoort, Nelspruit, and KwaZulu-Natal South Coast during the spring flush of 2021 and the summer flush of 2022 for anatomical analysis. Box plots illustrated significant variations in leaf and petiole anatomical traits among macadamia cultivars and regions. Cultivars ‘814′ and ‘695′ exhibited higher stomatal densities and higher vein densities, while cultivar ‘814′ also showed thicker mesophyll tissues and higher petiole Huber values. These traits suggest that cultivars ‘814′ and ‘695′ may have improved water transport and potential drought tolerance than cultivars ‘816′ and ‘A4’. Seasonal variation accounted for 45 % of the observed variability in leaf and petiole anatomy, highlighting a strong influence of environmental factors during leaf development. However, the anatomical variation was shaped not only by environmental factors but also by cultivar-specific characteristics. These findings suggest that these leaf and petiole anatomical traits could serve as indicators of drought tolerance and help improve the water management practices in macadamia cultivation, particularly in regions with inadequate rainfall. HIGHLIGHTS • The water requirements of macadamia trees remain unexplored. • Leaf and petiole anatomy varies significantly across cultivars and regions. • Environmental conditions and genetic factors influenced leaf and petiole anatomy. • Selecting drought-tolerant cultivars improves the water management practices in macadamia cultivation.Item Anti-acne and anti-hyperpigmentation potential of selected South African bryophytes with identification of oleamide as a lead compound(Elsevier, 2025-09) Paulsen, Alexander Quinn; Seaman, Jonathan Lloyd; Lall, Namrita; namrita.lall@up.ac.zaAcne vulgaris (AV), a chronic dermal inflammatory condition, affects approximately 9.4 % of the global population, with adolescents exhibiting the highest prevalence. Cutibacterium acnes is a key pathogenic factor in this chronic inflammatory condition, often resulting in post-inflammatory hyperpigmentation (PIH), which is primarily treated with tyrosinase inhibitors targeting melanin synthesis. While bryophytes are underexplored in modern cosmeceutical research, they have a history of use in traditional Chinese and Indian medicine for skin ailments. This study aimed to evaluate the antibacterial and anti-tyrosinase potential of three bryophyte species—Bryum argenteum Hedw., Fabronia pilifera Hornsch., and Leptodictyum riparium (Hedw.) Warnst.—to assess their utility in managing AV and PIH. Ethanolic (70 % v/v) extracts were prepared from rinsed and unrinsed plant material. Antibacterial activity against C. acnes (ATCC 6919) was assessed via PrestoBlue microtiter plate assays to determine the minimum inhibitory concentration (MIC) of the bryophyte ethanolic extracts. Tyrosinase inhibition was measured using colorimetric microtiter plate assays to evaluate anti-hyperpigmentation potential. Lead extracts were further analysed for their volatile constituents using gas chromatography-mass spectrometry (GC-MS). Rinsed B. argenteum extract exhibited the strongest antibacterial activity with an MIC of 31.25 μg/mL, followed by rinsed F. pilifera extract at 62.5 μg/mL. All extracts showed minimal tyrosinase inhibition, with IC₅₀ values exceeding the highest concentration tested. GC-MS analysis identified oleamide, a compound with known antibacterial properties, as the major volatile constituent (17.37 %–52.64 %), with the highest concentration of oleamide found in rinsed B. argenteum extract. These findings suggest that selected bryophytes, particularly B. argenteum, may serve as promising sources of antibacterial agents for the treatment of AV. Although pharmaceutically significant tyrosinase inhibition was not observed, the high oleamide content warrants further investigation through bioassay-guided fractionation. This study introduces bryophytes as novel candidates for cosmeceutical applications targeting acne-related skin concerns. HIGHLIGHTS • Determination of antibacterial activity of selected bryophyte species. • Variation in bioactivity and chemical profile between bryophyte extract preparations. • Antibacterial (Cutibacterium acnes) activity of rinsed Bryum argenteum and Fabronia pilifera with MICs of 31.25 μg/mL and 62.5 μg/mL respectively. • Oleamide is the primary volatile constituent of 70 % ethanolic B. argenteum and F. pilifera extracts.Item Adjuvant properties of selected medicinal plants for tuberculosis treatment(Elsevier, 2025-02) Kok, Anna-Mari; Meyer, Debra; Lall, Namrita; namrita.lall@up.ac.zaPlease read abstract in the article. HIGHLIGHTS • Many plant extracts with antimycobacterial activity have been identified recently. • Eucalyptus deglupta and Melianthus major had effective antioxidant capacity. • Searsia lancea showed significant hepatoprotection protection. • Increase in IL-12 by Eucalyptus deglupta and Sutherlandia frutescens.Item A review of the world's response to COVID-19 and the potential of medicinal plants for future pandemics(Elsevier, 2025-09) Alston, Brandon James; Maphutha, Jacqueline; Ackron, Jessica; Kok, Anna-Mari; Lall, Namrita; namrita.lall@up.ac.zaCoronavirus pandemics such as Spanish influenza, severe acute respiratory syndrome-coronavirus (SARS-CoV), middle east respiratory syndrome-coronavirus (MERS-CoV) and severe acute respiratory syndrome-coronavirus (SARS-CoV-2) have displayed high incidence and mortality rates prompting the need for repurposing of drugs, vaccine development and the investigation of medicinal plants. Research on previous coronaviruses has served as the foundation for COVID-19 (arising from SARS-CoV-2) research. Various medicinal plants such as Glycyrrhiza glabra, Ginkgo biloba, Curcuma longa and Artemisia annua have displayed favorable results against SARS-CoV-2. Medicinal plants as well as bioactive compounds derived from medicinal plants have been investigated in clinical trials to elucidate the effect on SARS-CoV-2. Several clinical trials evaluate the effect of the medicinal plant and bioactive compounds derived thereof on symptoms arising due to SARS-CoV-2 thus, the main aim of this review article is to highlight the gap in the investigation of the effect of medicinal plants and bioactive compounds on the specific mechanisms of COVID-19 in clinical trials. The review also highlights challenges pertaining to the standardization and quality control of medicinal plants as well as bioactive compounds derived from medicinal plants which may impede the feasibility of using medicinal plants in the clinical regimen for COVID-19 or future coronavirus pandemics. HIGHLIGHTS • SARS-CoV-2 is a highly infectious virus with high incidence and mortality rates. • Medicinal plants and bioactive compounds derived thereof are still relevant despite the use of repurposed antivirals (remdesivir) and vaccines. • Thorough clinical trials need to be conducted to elucidate the mechanism of action of medicinal plants and bioactive compounds derived thereof on COVID-19. • Gap in clinical trials leads to the use of unapproved medicinal plants and compounds which is a major health risk.Item Spatio-temporal dynamics of Isoberlinia-dominated woodlands in disturbance-prone landscapes over 15 years(Elsevier, 2025-06) Idjigberou, Shegoun Eudes; Assede, Emeline Sessi Pelagie; Biaou, Severin; Gouwakinnou, Gerard Nounagnon; Natta, Armand Kuyema; Biaou, Samadori Sorotori HonoreUnderstanding the impact of productivity and disturbance on vegetation succession is a crucial debate in community ecology, with significant implications for biodiversity conservation. Productivity and disturbance influence species richness and structure, enhancing our understanding of vegetation dynamics and species coexistence over time. Numerous theories, such as the Intermediate Stress Hypothesis, Intermediate Disturbance Hypothesis, and Dynamic Equilibrium Model, have been proposed to explain these mechanisms. However, our understanding of how productivity and disturbance affect the spatio-temporal dynamics of Isoberlinia-dominated woodlands remains limited. We analyzed floristic data from sixteen sites with 64 permanent plots (400 m² each) along a south-north precipitation gradient (1112–991 mm per year) over 15 years (2006–2020). We calculated species richness and density for sapling and adult trees, and estimated two main variables: potential productivity using water deficit as a proxy, and disturbance intensity using logging rate. A linear mixed effects model, with plots nested within sites as random variables, was developed to test the effect of potential productivity and level of disturbance on species richness and density, for sapling and adult trees. Our results showed that species richness (SR) and density, for saplings and adult trees decreased over time, regardless of the disturbance and potential productivity gradients. Compared to higher levels of disturbance, low and medium levels of disturbance significantly increase the species richness of saplings and adult trees. In addition, the density of adult trees and saplings decreased over time, but increased with the level of disturbance from high to low. These results suggest that increased disturbance reduces the density of woodland species in favor of invasive species, typically savanna species. Overall, our results are consistent with the Dynamic Equilibrium Model, highlighting the complex interactions between disturbance regimes, productivity gradients, and their effects on species richness within ecosystems. Efficient forest management in Isoberlinia-dominated would avoid the high levels of logging that promote the establishment of invasive species and would maintain the biodiversity of this ecosystem in the long term. HIGHLIGHTS • Examined how the productivity and disturbance affect the spatio-temporal dynamics of Isoberlinia-dominated woodlands. • Analyzed data from 64 permanent plots along a south-north precipitation gradient over 15 years. • Species richness and density for saplings and adult trees decreased over time. • Low to medium disturbance levels increase the richness of saplings and adult trees compared to higher levels. • Increased disturbance favored invasive savannah species over woodland species.Item A third biodiversity metric in the third pole(Wiley, 2025-04) Oberlander, Kenneth Carl; kenneth.oberlander@up.ac.zaThe readers of this journal need no introduction to the threat posed to biodiversity by anthropogenic factors such as habitat degradation and climate change. The (sometimes considerable) efforts by many national governments to increase biodiversity protection over the last few decades, via the establishment of protected areas for conservation, have nevertheless met with criticism, particularly with regard to the evidence base used for the establishment and expansion of such protected areas (Maxwell et al. 2020). This is particularly acute for regional planning efforts involving multiple governments, where the effects of national borders on biodiversity conservation may have profound consequences in the near future (Li et al. 2025). Ideally, such decisions should be made taking into account evidence from multiple different levels of biological organisation, but this is seldom achieved in reality.Item Effect of storage conditions on soybean seed quality produced by smallholder farmers within two districts of Gauteng, South Africa(University of Kassel, 2024) Mahlangu, A. Zanele; Truter, Mariette; Kritzinger, Quenton; zanele.mahlangu@up.ac.zaSeed quality comprises of physical, physiological, and health attributes. Moreover, significant aspects of seed quality include seed viability and vigour. Maintaining good seed quality under sub-optimal storage conditions is one of the major challenges smallholder soybean farmers face. Hence, this study aimed to determine the effect of on-farm storage conditions on the seed quality of soybeans from smallholder farmers within the Gauteng Province, South Africa. The objectives of this study were to i) evaluate and compare the viability and vigour of farm-saved soybean seeds, and ii) evaluate the effect of seed moisture and simulated storage period on the rate of deterioration of the seeds. Farm-saved seed samples collected from the twenty-two smallholder farmers from two districts within the Gauteng Province showed significant variations in terms of seed moisture, viability, vigour [accelerated aging (Aa) and conductivity], and in the rate of deterioration. The seed moisture content ranged from 7.8-30.8 %. The majority of the farm-saved seed samples had a germination percentage significantly higher than 75 %, irrespective of the storage conditions. On the other hand, seeds subjected to Aa and to the controlled deterioration test resulted in less vigourous seedlings. Seeds that were subjected to 24 hr Aa had a significantly (p < 0.05) higher germination than those subjected to 72 hr Aa. The 72 hr Aa results verified the reduction of seed vigour as the storage period increased. A similar declining germination trend was observed on seeds subjected to deterioration tests under high moisture content levels. The study gives an indication of how the sub-optimal storage facilities used by smallholder soybean farmers affect seed quality. Based on the vigour tests, it can be assumed that storing seeds with high SMC under high relative humidity coupled together with high temperatures for prolonged periods tends to deteriorate the seeds rapidly and thus reduce seed vigour.Item Biotic pressure outweighs the influence of resource availability on physical defence investment in a tropical tree(Oxford University Press, 2025-06) Babah Daouda, Bio Barriou; Kouagou, M'Mouyohoun; Assede, Emeline Sessi Pelagie; Gaoue, Orou G.Plants have long-lasting and complex interactions with herbivores, including insects and mammals. In response to high herbivory rates, plants either tolerate biomass loss or develop several defence mechanisms, such as physical defence. The resource availability hypothesis (RAH) predicts that plant defence investment is dependent on resource availability and plant's life history. However, the effect of resource availability on plant investment in defence is mediated through biotic pressure. We tested the effects of soil qualities and browsing pressure on the physical defence and reproductive investments in Acacia sieberiana at the Pendjari Biosphere Reserve in West Africa. We selected six populations, including three in the Pendjari River floodplain where soil moisture is high but with high elephant browsing pressure, and three populations on the plateau in the hunting zone where soils are drier and relatively poorer with a lower density of elephants. We found greater investment in physical defence for trees in the floodplain. Furthermore, A. sieberiana trees produced less fruit in the floodplain than in the plateau. Contrary to the predictions of the RAH, we found more and longer thorns in populations in the richer floodplains than on the plateau. This was linked to higher elephant browsing pressure in the floodplains. This physical defence was probably induced to cope with the episodic but high levels of herbivory observed in this environment. Surprisingly, the negative influence of thorn number and size on the likelihood of elephant damage was observed only in the rich floodplains and not in plateau sites. Altogether, our study demonstrates that the influence of resource availability (soil moisture, pH, and fertility) in shaping plant physical defence can be outweighed by high herbivory pressure.Item Bark investment is key to forest expansion into African savannas by conferring resistance to fire and seasonal drought(Oxford University Press, 2025-05) Rosell, Julieta A.; Vetter, Susanne; Olson, Mark E.; Greve, MichelleBACKGROUND AND AIMS : Forest expansion into savannas is widespread even though fire and seasonal drought provide environmental conditions against encroachment by forest specialists. A distinct suite of species can establish under savanna trees, forming bush clumps and facilitating forest establishment. Understanding the functional traits of clump-forming species is crucial for uncovering encroachment mechanisms and devising management strategies. Bark likely plays a key role in enabling clump initiation. Fire resistance can be achieved by accumulation of outer bark thickness (OBT), height and/or stem diameter (SD), while drought resistance may be enhanced by greater inner bark thickness (IBT), associated with water and carbohydrate storage. METHODS : We selected representative savanna, clump-forming and closed-canopy species (ecological categories) at two South African sites experiencing forest expansion and differing in rainfall and fire frequency. We compared OBT–SD and IBT–SD allometries across ecological categories and sites and examined whether categories separated along axes reflecting fire/drought resistance (OBT and IBT) and resource allocation strategy (density and water content, leaf size). KEY RESULTS : OBT–SD scaling of clump-forming species was more similar to savanna than forest species, and savanna species at the more fire-prone savanna had steeper OBT–SD scaling, consistent with high OBT providing fire protection in early clump formation. Similar IBT–SD slope across groups was consistent with similar metabolic needs, while higher intercepts in savanna and clump-forming species indicated higher water storage. ‘Cheap’ low-density tissues in savanna species allow fast accumulation of SD and OBT and resistance to fire topkill. Closed-canopy species had denser tissues and thin stems and bark for a given height, while the clump-forming species were intermediate. CONCLUSIONS : Bark and probably other traits are key in the capacity of some species to form bush clumps. Identifying these traits and the mechanisms underlying clump formation is essential for managing encroached savannas and grasslands.Item Assessing the use of remotely sensed surface water flux to estimate net groundwater storage change in an aquifer predominantly used for irrigation(Elsevier, 2025-07) Viviers, Cindy; Van der Laan, MichaelPlease read abstract in the article.Item Assessing extensive pasture-based beef production in South Africa under future climate change conditions(Elsevier, 2025-10) Magona, Christopher; Hassen, Abubeker; Tesfamariam, Eyob Habte; Mengistu, Michael; Visser, Carina; Oosting, Simon; Van der Linden, Aart; carina.visser@up.ac.zaCONTEXT : Assessing the impact of climate change on extensive pasture-based beef production across varied agro-ecological regions is crucial for designing customized adaptation measures. OBJECTIVE : This study assesses the effects of climate change on extensive pasture-based beef production systems in three South African agro-ecological regions (Bloemfontein, Phalaborwa and Buffalo Berlin) under two climate change scenarios, namely the representative concentration pathways (RCPs) 4.5 and 8.5. METHODS : The LiGAPS-Beef model, previously calibrated for the region, was used to evaluate the impact of climate change on beef cattle production under pasture-based extensive systems. Four breed types, namely Bos taurus, Composite, Zebu indicine and Sanga cattle were included in this study. Genetic parameters for each breed were obtained from SA Stud Book, Livestock Registering Federation (LRF) and literature. Measured historical weather data was obtained from the South African Weather Service for the three agro-ecological regions. An ensemble of eight regional climate model (RCA4) simulations from the CORDEX Africa initiative was used to generate future climate change projection data for the period 2036–2065 under RCP 4.5 and RCP 8.5 scenarios. The future nutritional composition data for forage was collected from studies that simulated and predicted future forage quality under climate change conditions. RESULTS AND CONCLUSION : The study found that the baseline average daily gain (ADG) was significantly higher (0.40 kg/head/day) than the simulated RCP 4.5 (0.21 kg/head/day, −48 %) and RCP 8.5 (0.20 kg/head/day, −51 %) ADGs regardless of breed type when both feed quality and feed quantity limited growth. Although the effect of the climate change scenarios on beef production was agro-ecological region dependent, the performance of Bos taurus declined more than other breeds under future climate scenarios while the Sanga and the Composite types were the most resilient, especially in hot climate areas. Model simulations predict that future climate change will have a greater negative impact on cattle in Buffalo Berlin and Phalaborwa, while those in Bloemfontein will be least affected. The study also highlights that under future climate change scenarios, pasture quality will be the key factor influencing cattle growth in Bloemfontein and Buffalo Berlin, while pasture quantity will be the dominant factor in Phalaborwa if stocking rates remain unchanged. The study highlights the need for nutritional and pasture management interventions for pasture-based extensive system (e.g., feed supplementation, adjusting the stocking rate to match pasture availability, identifying and integrating drought and/or heat tolerant ecotypes, fodder trees that provide shade for the animals) to mitigate the expected decline in beef cattle performance in South African agro-ecological regions. SIGNIFICANCE : Quantifying the impact of anticipated climate change on pasture-based extensive beef production and identifying specific factors that limit beef production per breed type in the different agro-ecological regions is crucial for assessing the potential ramifications on beef production. This information empowers farmers and policy makers to develop targeted mitigation and adaptation strategies that promote resilience of the beef production system in the respective regions. HIGHLIGHTS • Quantifying climate change impact on beef production is vital for coping measures. • Beef cattle growth was simulated under RCP 4.5 and RCP 8.5 in South Africa. • 2050 simulated growth declined by 48 % in RCP 4.5 and 51 % in RCP 8.5 from baseline. • Growth of Bos taurus was most adversely affected, but Sanga was the most resilient. • Location-specific intervention is vital to sustain beef production in South Africa.Item Proposals to conserve the name Aloe mitriformis with a conserved type and the name A. microstigma against A. perfoliata (Asphodelaceae: Alooideae)(Wiley, 2025-06) Klopper, Ronell Renett; Smith, Gideon F.; Van Wyk, Abraham Erasmus (Braam)No abstract available.Item In vitro antiplasmodial activity and cytotoxicity of three Ziziphus (Rhamnaceae) species from South Africa(Elsevier, 2025-06) Mabuza, Mcebisi Junior; Kaiser, M.; Tshikalange, T.E.; Yusuf, Abdullahi Ahmed; Bapela, Mahwahwatse JohannaPlease read abstract in the article.Item Occurrence and genotypic characterization of selected multidrug-resistant ESKAPE-E pathogens isolated from integrated smallholder fresh produce farms(Elsevier, 2025-06) Viviers, Sheldon A.; Richter-Mouton, Loandi; Featherston, Jonathan; Korsten, Lise; lise.korsten@up.ac.zaAntimicrobial resistance (AMR) ranks among the top ten global public health threats, with extended-spectrum β-lactamase (ESBL)-producing Enterobacterales and Pseudomonas aeruginosa emerging as multidrug-resistant (MDR) priority pathogens. This study aimed to evaluate the presence and characteristics (phenotypic and genotypic AMR profiles) of ESBL/AmpC-producing Enterobacterales and P. aeruginosa isolates obtained from the water-soil-plant nexus on smallholder fresh produce farms in South Africa. Samples of irrigation water (n = 44), soil (n = 85), and fresh produce (n = 95) were collected from six smallholder farms. Potential MDR bacteria were isolated using selective enrichment, chromogenic media, and identified with MALDI-TOF MS. Antimicrobial resistance was assessed via double-disk diffusion against 13 different antibiotic classes, while 20 selected isolates were genotypically characterized using whole-genome sequencing (WGS) (Illumina MiSeq). ESBL/AmpC-producing isolates were detected in 17% of samples (38/224), primarily from fresh produce (54%), followed by soil (31%) and water (15%). The dominant Enterobacterales species identified from all three matrices included Enterobacter spp. (26%), Klebsiella spp. (26%), Serratia spp. (17%), and Escherichia coli (9%). Phenotypically, 47% and 43% of the isolates were classified as ESBL and AmpC-producers, respectively, with resistance to beta-lactams, aminoglycosides, and glycylcyclines. Notably, WGS analysis indicated the presence of clinically significant AMR and virulence genes among isolates from the environment, particularly those associated with mobile genetic elements. The results from the study add to the limited national and international knowledge of AMR prevalence in the smallholder agricultural landscape, needed for the introduction of appropriate intervention strategies and future risk assessment of the informal supply chain.Item Entomopathogenic nematodes : commercial use and future perspectives(Elsevier, 2025-09) Ramakuwela, Tshimangadzo; Tarasco, Eustachio; Chavarría-Hernández, Norberto; Toepfer, Stefan; tshimangadzo.ramakuwela@up.ac.zaThe 100 years of research, development, commercialization and use of entomopathogenic nematodes (EPN) since their discovery in the 1920s have seen impressive progress. Nowadays, many EPN products, based on a relatively limited number of EPN species, are commercially available in most world regions. This paper presents a review of EPN commercialization and examples of EPN use in field crops such as maize and in agroforestry ecosystems. It demonstrates how EPN have become an important tool in biological control of insect pests offering many advantages over chemicals. These include farmer and consumer safety, minimal damage to natural enemies, no problems with pollinators, and no environmental pollution. All of these attributes are essential for an advanced and sustainable integrated pest management strategy. We explored future potential of commercialization and adoption of EPN-based biocontrol products. The future may lie in several advances: i) The ability to tailor the use of EPN to broad as well as to local agricultural needs. ii) Enhancing their shelf life and efficacy through genetic improvements. iii) Refining application technologies. iv) Improving mass production (including machine learning using production data). v Reducing production and delivery costs, considering EPN as safe agents and therefore reducing registration burdens. Vi) Finally, expanding their use to a larger market such as to new pest species and crops. With continued research and innovation, EPN could become a cornerstone of sustainable pest management strategies in an increasing number of countries.Item Improving the antinutritional profiles of common beans (Phaseolus vulgaris L.) moderately impacts carotenoid bioaccessibility but not mineral solubility(Nature Research, 2024-05-24) Alvarado‑Ramos , Katherine; Bravo‑Nunez , Angela; Halimi , Charlotte; Maillot , Matthieu; Icard‑Verniere, Christele; Forti, Chiara; Preite, Chiara; Ferrari, Luisa; Sala, Tea; Losa, Alessia; Cominelli, Eleonora; Sparvoli, Emanuela Camilli Francesca; Lisciani, Stefania Marconi Silvia; Georgé, Stephane; Mouquet-Rivier, Claire; Kunert, Karl J.Common beans are a common staple food with valuable nutritional qualities, but their high contents in antinutritional factors (ANFs) can decrease the bioavailability of (i) fat-soluble micronutrients including carotenoids and (ii) minerals. Our objective was to select ANF-poor bean lines that would not interfere with carotenoid and mineral bioavailability. To achieve this objective, seeds of commercial and experimental Phaseolus vulgaris L. bean lines were produced for 2 years and the bean’s content in ANFs (saponins, phytates, tannins, total polyphenols) was assessed. We then measured carotenoid bioaccessibility and mineral solubility (i.e. the fraction of carotenoid and mineral that transfer into the aqueous phase of the digesta and is therefore absorbable) from prepared beans using in vitro digestion. All beans contained at least 200 mg/100 g of saponins and 2.44 mg/100 g tannins. The low phytic acid (lpa) lines, lpa1 and lpa12 exhibited lower phytate levels (≈ − 80%, p = 0.007 and p = 0.02) than their control BAT-93. However, this decrease had no significant impact on mineral solubility. HP5/1 (lpa + phaseolin and lectin PHA-E free) bean line, induced an improvement in carotenoid bioaccessibility (i.e., + 38%, p = 0.02, and + 32%, p = 0.005, for phytofluene bioaccessibility in 2021 and 2022, respectively). We conclude that decrease in the phytate bean content should thus likely be associated to decreases in other ANFs such as tannins or polyphenols to lead to significant improvement of micronutrient bioaccessibility.Item Standing vegetation and seed bank patterns paint a bleak picture for urban grassland restoration(Springer, 2025-04) Malherbe, Misha; Le Roux, Peter Christiaan; Haussmann, Natalie S.; peter.leroux@up.ac.zaUrbanisation and urban sprawl are major drivers of global habitat transformation and biodiversity loss. Natural vegetation in urban areas is confined to remnant patches and, as a result, the conservation of these patches of vegetation is becoming increasingly important for biodiversity conservation. Globally grasslands experience high rates of transformation and are threatened by expanding urban areas, causing fragmentation, and facilitating the spread of invasive species. This study explores how above- and belowground vegetation communities within remnant grassland patches vary as a function of patch connectivity and patch size in the City of Tshwane, Gauteng, South Africa. We sampled twelve sites from eleven nature reserves within Tshwane to investigate the relationships between urbanisation and vegetation characteristics. Tshwane’s grassland patches have high levels of invasion, with alien species making up a considerable portion of both standing (13% richness and a third of cover) and seed bank vegetation (31% richness and 26% abundance). Furthermore, we found low similarity between standing vegetation and the seed bank (mean ± SD = 0.25 ± 0.06). Neither road density nor reserve size were related to the total cover or richness of vascular plants, nor the cover or richness of alien species. Similarly, neither variable predicted above-belowground similarity. This suggests that the connectivity of remnant grassland patches does not have any significant effect on vegetation characteristics in this disturbed urban environment. Our results indicate that restoration relying only on natural revegetation from the seed bank is unlikely to be effective and we suggest that active restoration interventions, such as reseeding and invasive species control, may be needed to restore these grasslands and improve their long-term conservation value.Item Avocado rhizosphere community profiling : white root rot and its impact on microbial composition(Frontiers Media, 2025-05) Magagula, Phinda; Swart, Velushka; Fourie, Arista; Vermeulen, Alicia; Nelson, Johannes Harold; Van Rooyen, Zelda; Van den Berg, Noelani; noelani.vdberg@fabi.up.ac.zaINTRODUCTION : The avocado rhizosphere supports diverse microbial communities essential for plant health and defence against pathogens. This study aimed to investigate the impact of Dematophora necatrix, the causal agent of white root rot (WRR), on the microbial composition and soil physicochemical properties of infected and non-infected avocado trees in two South African orchards. METHODS : ITS and 16S metabarcoding was used to compare the composition and diversity of the rhizosphere microbiome. Soil physicochemical properties were also assessed, and culturable bacterial and fungal isolates from the rhizosphere were screened for antagonistic activity against D. necatrix. RESULTS : We found that D. necatrix did not significantly alter overall microbial diversity but influenced relative abundance of specific taxa. In Orchard A, dominant bacterial genera included Sphingomonas, Rokubacteriales and Lysobacter, while Orchard B featured Sphingomonas and Acidothermus while beneficial microbes such as Streptomyces and Bacillus were enriched in WRR non-infected (WRR-N) soils. The fungal profiles revealed Trichoderma and Penicillium as potential biocontrol agents enriched in WRR-N soils. Furthermore, dual-culture assays demonstrated that Bacillus, Pseudomonas, Penicillium and Trichoderma isolates inhibited D. necatrix, highlighting their biocontrol potential. Key parameters, such as soil pH and iron (Fe), correlated strongly with microbial composition, suggesting they play an important role in pathogen resilience. DISCUSSION : These findings underscore the complexity of the avocado rhizosphere and its role in managing WRR, offering a foundation for developing integrated disease management strategies to enhance avocado productivity.Item Removal of organic biomass in Eucalyptus plantations has a greater impact on fungal than on bacterial networks(Elsevier, 2025-06) Bose, Tanay; Vivas, Maria; Slippers, Bernard; Roux, Jolanda; Dovey, Steven; Kemler, Martin; Begerow, Dominik; Witfeld, Frederick; Brachmann, Andreas; Wingfield, Michael J.; Hammerbacher, Almuth; tanay.bose@fabi.up.ac.zaComplex and stable soil microbial networks are essential for productivity in plantation forestry, but their response to disturbances from harvesting and replanting is not well understood. This study assessed the impact of treatments designed to mitigate these disturbances on microbial biodiversity and networks in Eucalyptus plantation soils at three South African sites. We used high-throughput sequencing to catalogue fungal and bacterial biodiversity from 108 soil samples across three treatments: (i) retention of harvest residues (retained), (ii) removal of residues (removed), and (iii) removal of residues with added fertilizer (fertilized). Bioinformatic and statistical analyses of the sequence data revealed treatment-specific variations in microbial OTU richness, network structure and taxon associations at order-level. Microbiome richness was highest in ‘retained’ plots, and treatment-specific microbial diversity was evident in both fungal and bacterial communities. Network comparisons revealed that treatments to mitigate disturbances caused by harvesting significantly affected fungal networks but not bacterial networks. Fungal networks in ‘retained’ plots exhibited the highest complexity and stability compared to plots where the entire crop was removed. However, bacterial networks did not show significant differences in network structure among treatments. The associations between fungal and bacterial nodes were consistent in the three treatments, as indicated by similar Jaccard indices. However, distinct fungal hub nodes were found when comparing the 'retained' and 'removed' treatments. These findings highlight that retaining harvest residues enhances microbial richness and stabilizes fungal networks, making it a better strategy for managing soil disturbances than residue removal or fertilization.