Endophytic fungi have emerged as vital allies in enhancing plant resilience to abiotic stresses, offering significant potential for climate-smart agriculture (CSA). This mechanistic review synthesises physiological, biochemical, and molecular pathways through which these symbionts mitigate stress, emphasising mechanistic understanding over descriptive diversity. Key mechanisms include osmotic regulation, ion homeostasis, antioxidant defence, hormonal modulation, and epigenetic reprogramming. As demonstrated by studies on Trichoderma harzianum, Fusarium solani, and Piriformospora indica, such interactions allow plants to sustain photosynthesis, nutrient uptake, and growth when subjected to drought, salinity, heat, and heavy metal stress. Comparative insights highlighted lineage-specific strategies: Ascomycota display broad-spectrum regulation through metabolite production and hormonal control; Basidiomycota specialise in root-fungus signalling and resource acquisition; and Zygomycota contribute primarily to nutrient mobilisation and rapid colonisation. Collectively, these insights reveal that endophytes act as "hidden regulators" of plant stress resilience. Integration of fungal symbionts into CSA practices holds considerable potential for improving productivity, adaptation, and mitigation, particularly in stress-prone agroecosystems. Yet, as several sources have argued, key gaps remain including field performance is inconsistent across host genotypes, beneficial and pathogenic traits sometimes overlap, and inoculant mass production is still limited. Addressing these challenges will necessitate omics-driven innovations, efficient delivery methods, improved relationships between empirical biological research and on-farm application, and policy frameworks. Overall, this synthesis highlights endophytic fungi as essential partners in building resilient and sustainable food systems under changing climates.

Fungal bio-control agents (BCA) can minimize use of agro-chemicals while increasing plant productivity and tolerance to biotic-abiotic stressors. Ideally, BCA should tolerate varying environmental conditions they are introduced into, to successfully dominate and protect plants from stressors. However, BCA are living micro-organisms, their survival and efficacy can be impeded by extreme conditions. The current study aimed at evaluating whether indigenous fungal isolates, viz, Aspergillus flavus, A. terreus, Penicillium sp. AL-38 IRH-2012b, Talaromyces minioluteus, T. purpureogenus, T. sayulitensis, Trichoderma ghanense and T. viride can tolerate different levels of salinity, pH, nutrient and temperature. Certain fungal species are pests with potential of destroying many crops; the pathogenic effects of the aforementioned fungal isolates were further assessed on different crops’ seeds. The results showed that, although being indigenous, Aspergillus, T. sayulitensis and T. ghanense failed to thrive in high salinity and pH. While Penicillium sp. AL-38 IRH-2012b failed to thrive under reduced nutrient level and all fungal isolates failed to grow at 10–20 °C. Furthermore, it was noted species within the same genus could affect crops in both favorable and unfavorable ways. The study demonstrated that the selected indigenous fungal isolates can tolerate different abiotic conditions and have potential to improve seed germination and seedling growth.

Using nematode resistant varieties is one of effective and environmental sound strategies being adopted in the management of economically important Meloidogyne species. Wild cucumber (Cucumis africanus) has been reported to possess resistance to Meloidogyne species. Two mechanism of nematode resistance, pre- and post-penetration resistance, had been identified, with post-penetration mechanism being used in plant breeding programs and crop rotation systems. The objective of this study was to determine the mechanism of nematode resistance in C. africanus to M. incognita and M. javanica. 6 weeks old C. africanus seedlings were separately inoculated with 100 s-stage juveniles (J2) of M. incognita and M. javanica. For 30 days, five seedlings were harvested from both M. incognita and M. javanica experiments every other day. Seedlings’ roots were examined for necrotic spots, rootlet interferences, giant cells and root gall numbers as indicators of successful or unsuccessful nematode penetration. Harvesting times were highly significant (P ≤ 0.01) on necrotic spot, rootlet interference and root gall numbers in both C. africanus—M. incognita and—M. javanica relations, but were not significant for giant cell number in C. africanus—M. incognita. The results suggested that C. africanus have post-penetration nematode resistance to both Meloidogyne species.

Potato (Solanum tuberosum L.) is a well-known food crop that is regarded as an important component in the worldwide battle against hunger and malnutrition. Root-knot nematodes (RKN), Meloidogyne species, are a serious limitation in the potato industry. Potato, being a tuberous crop, yield reduction is mainly due to tuber quality and quantity. In order to evaluate the response of five commercial potato cultivars, viz ‘Buffelspoort 1’, ‘Hertha’, ‘Larnoma’, ‘Mnandi’ and ‘Up-to-date’ to two RKN species, viz M. enterolobii and M. javanica; pot experiments were conducted under net house conditions. Ten separate experiments, each with treatments: 0, 500, 1500, 2500 and 3500 eggs + second-stage juveniles (J2), were arranged in a randomized complete block design (RCBD) with five replicates. Fifty-six days after inoculation, nematode effect on plant yield was evaluated. Potato tubers were assessed for root galls, and nematodes reproductive factor (RF) was computed. There were significant differences amongst treatments on the following potato growth parameters: plant height, stem diameter, chlorophyll content, number of tubers and tuber weight in both M. enterolobii and M. javanica (P ≤ 0.05). The RF was above unity (one) in all potato cultivars for both M. enterolobii and M. javanica; with M. enterolobii showing more aggressiveness compared to M. javanica. Further, cultivars ‘Buffelspoort 1’ and ‘Hertha’ showed the highest susceptibility, whilst cultivar ‘Mnandi’ showed the least susceptibility. Infection of potato cultivars by the nematodes had severe effects on growth parameters of all the cultivars. Results suggested that all five commercial potato cultivars were susceptible to M. enterolobii and M. javanica. Thus, there is an urgent need for RKN management intervention in the aforementioned cultivars.

Dry bean (Phaseolus vulgaris L.) is an important commercialized field crop in South Africa for aiding in food security as a cheap protein source. However, it is highly susceptible to root-knot nematodes (RKN), Meloidogyne species. Use of indigenous nematophagous fungi as bio-control agents (BCA) of Meloidogyne nematodes is a promising research focus area. This is because indigenous fungal species are naturally part of the ecosystem and therefore compatible with other biological processes unlike most synthetic chemicals. The objective of the study was to identify indigenous nematophagous fungal BCA and establish their potential efficacy in reducing M. enterolobii population densities on dry bean with and without incorporation of compost. Screened indigenous fungal species included Aspergillus terreus, Talaromyces minioluteus, T. sayulitensis, Trichoderma ghanense, and T. viride. There were observed significant parasitism differences (P ≤ 0.05) among the BCA, with T. ghanense showing the highest egg parasitism (86%), followed by T. minioluteus (72%) and T. sayulitensis (70%). On the other hand, the highest J2 parasitism was observed on T. minioluteus (95%), followed by A. terreus and T. viride (63%). A similar trend was observed under in vivo conditions, with higher efficacy with compost incorporation. This provides a highly encouraging alternative and ecologically complementary Meloidogyne management in dry bean production.