Bambara groundnut (Vigna subterranea L. Verdc) is grown by smallholders and subsistence farmers in the marginal parts of sub-Saharan Africa. This legume is native to Africa and is cultivated throughout semi-arid sub-Saharan Africa. It is hardy and has been recognized as a nutritious food source in times of scarcity. Drought can negatively affect the germination or establishment of seedlings in the early stages of crop growth. Drought can limit the growing season of certain crops and create conditions that encourage the invasion of insects and diseases. Drought can also lead to a lack of crop yield, leading to rising food prices, shortages, and possibly malnutrition in vulnerable populations. A drought-tolerant genotype can be identified at the germination stage of Bambara groundnut by screening for drought-tolerance traits, and this knowledge can be applied to Bambara crop improvement programs to identify drought-tolerant traits during early growth phases. As an osmolyte, polyethylene glycol (PEG 6000) reduced water potential and simulated drought stress in Bambara groundnut seeds of different genotypes. Osmolytes are low-molecular-weight organic compounds that influence biological fluid properties. In this study, 24 Bambara groundnut genotypes were used. Data were collected on seed germination percentage (G%), germination velocity index (GVI), mean germination time (MGT), root dry mass (RDM), root fresh mass (RFM), and seven drought tolerance indices: mean productivity (MP), tolerance index (TOL), geometric mean productivity (GMP), stress susceptibility index (SSI), yield index (YI), yield stability index (YSI), stress tolerance index (STI) as well as seed coat color measurements. The data were applied to the mean observation of genotypes under simulated drought conditions (Ys) and the mean observation of genotypes under controlled conditions (Yp). Germination%, germination velocity index (GVI), mass germination time (MGT), and root fresh mass (RFM) differed significantly (p < 0.001) between the two stress conditions. Bambara genotypes Acc 82 and Acc 96 were found to be the most drought-tolerant.

Extracellular vesicles (EVs) are tiny messengers that convey bioactive molecules from donor to recipient cells, leading to changes in their physiology and function. We investigated the role of EVs in shaping growth and the biofilm biology of the tree pathogen Fusarium circinatum and its interaction with the susceptible host, Pinus patula. Vesicles were collected from fungal planktonic and biofilm cultures and from pine seedling needles and roots. The physical properties of these vesicles were analysed using nanoparticle tracking analysis and transmission electron microscopy, which revealed a diverse range of sizes and shapes, respectively. Furthermore, uptake of vesicles by conidia was conducted. The results demonstrated that F. circinatum EVs significantly but variably affected spore viability during the early phase (2-4 h) although they enhanced fungal biofilm integrity. In contrast, P. patula EVs greatly inhibited hyphal formation and biofilm biomass, but failed to inhibit matrix production in the fungal biofilm. Our results therefore show that conidial germination is essential for late fungal development including hyphal and biofilm formation while matrix production is a counter measure against harsh environmental conditions including the effects of plant-derived EVs.

Much of what we know about the biological impacts of vesicles (MVs) is derived from Arabidopsis thaliana. Our study focused on vesicles from species in the non‐model plant group, Pinus (pine) (P. elliottii, P. radiata, and P. patula × Pinus tec (hybrid)). These plants have tougher tissues and strong, acicular‐shaped leaves (needles). Herein, we first developed a protocol to guide effective collection of juice fluid from needles and roots in a clean and efficient manner. The effects of these vesicles were characterized in terms of the global nutrient profile of the pine pitch canker fungus, Fusarium circinatum, generated from growing fungal spores on ~400 substrates embedded across BioLog phenotypic microarray (PM) plates (PM1, PM2A: carbon sources; PM3B: nitrogen sources; PM9: osmolytes/pH; PM24C: chemicals). Our findings revealed that MVs, specifically needle‐derived MVs (ndMVs) from P. elliottii, disrupt metabolite assimilation in several important pathways, including carbon and nitrogen metabolism. The PM data were also strongly correlated with observed phenotypic effects, including reduced viability and germination of spores in liquid media, as well as impaired filamentous growth on solid media. Importantly, these MV‐induced phenotypic effects were reproducible in other filamentous pathogens (e.g., Botrytis cinerea, Chrysoporthe cubensis and F. graminearum) and during a glasshouse trial conducted with F. circinatum‐infected P. elliottii seedlings, demonstrating the stable biological effects of ndMVs. Cumulatively, our results suggest that plant‐derived vesicles can disrupt metabolism in pathogenic fungi and, therefore, serve as a cost‐effective and sustainable source of novel plant protection molecules.

Extracellular vesicles (EVs) are tiny messengers that convey bioactive molecules from donor to recipient cells, leading to changes in their physiology and function. We investigated the role of EVs in shaping growth and the biofilm biology of the tree pathogen Fusarium circinatum and its interaction with the susceptible host, Pinus patula. Vesicles were collected from fungal planktonic and biofilm cultures and from pine seedling needles and roots. The physical properties of these vesicles were analysed using nanoparticle tracking analysis and transmission electron microscopy, which revealed a diverse range of sizes and shapes, respectively. Furthermore, uptake of vesicles by conidia demonstrated that F. circinatum EVs significantly but variably affected spore viability during the early phase (2-4 h) although they enhanced biomass and extracellular matrix (ECM) production in biofilms. In contrast, P. patulaEVs greatly inhibited hyphal formation and biofilm biomass, but failed to inhibit ECM biosynthesis in the fungal biofilm. Our results therefore suggest that conidial germination is essential for late fungal development including hyphal and biofilm formation while matrix production may be a counter measure against harsh environmental conditions including the effects of plant-derived EVs. Therefore, plant-microbe interactions viewed within the context of biofilm formation can improve understanding into the dynamic and complex behaviours of fungal pathogens and their interactions with plant hosts.