W. Chan-Cupul, J. M. Palma-Garcia, E. Ruiz-S & aacute;nchez, and E. Cruz-Crespo. 2025. Assessment of the effects of inoculation with entomopathogenic fungi on the vegetative growth and yield of Capsicum chinense under water stress conditions. Int. J. Agric. and gastronomic value. The cultivation of C. chinense is increasingly challenged by global warming and droughts, which impact both plant health and market stability. Climate change affects agriculture by altering temperature and precipitation patterns, leading to soil moisture loss, drought, phenological damage, and increased pest and disease incidence. The use of bioinoculants, including entomopathogenic fungi (EFs), may be a strategy to mitigate drought in C. chinense production. The aim of this study was to assess the impact of Beauveria brongniartii and Purpureocillium lilacinum inoculation on the vegetative growth and yield of C. chinense var. Chichen Itza under two water stress conditions. Experiments were conducted in a gothic greenhouse, and C. chinense seedlings were transplanted into growth bags [coconut fiber (70%) and dust (30%)] with controlled irrigation at 75% and 100% levels. The EFs were applied weekly for the first month (50 mL at 1x107 conidia mL-1). Agronomic parameters, including plant height, stem diameter, chlorophyll index, leaf area, fruit quality, and yield, were measured. The results indicated that both B. brongniartii and P. lilacinum significantly increased plant height and stem diameter in the early stages of growth under water stress conditions. B. brongniartii notably increased plant growth and maintained fruit yield even under reduced irrigation. However, no significant differences were observed in the chlorophyll index or overall fruit yield among the treatments. The results of this study suggest that B. brongniartii and P. lilacinum can improve C. chinense resilience to water stress, suggesting potential applications in sustainable agriculture amidst climate change.

Salt stress is a significant abiotic stress that adversely affects pepper plant growth which can accelerate the development of plant pathogens and increase plant susceptibility to diseases. Verticillium dahliae, which causes pepper wilt disease, is an important biotic stress factor. Funneliformismosseae and biochar organic wastes help to take nutrients from the soil by establishing symbiotic connections with plant roots and, are effective in treating plant diseases, plant growth, and stress tolerance. This study aims to determine the effects of F. mosseae (Fm) and 2% biochar (Bc) against V. dahliae (Vd) on some plant physiological properties, plant nutrient uptake, soil pH, and EC value in pepper plants grown under salt stress (50mM, 100mM, 150mM). As a result of the study, the use of F. mosseae alone or in interaction with 2% biochar significantly increased some physiological parameters and some minerals (P, K, Mg, and Mn) contents of the plant. Moreover, pepper plants showed remarkable resistance to salt and stress factors caused by V. dahliae. In addition, the interaction between F. mosseae and biochar significantly lowered the soil EC value under conditions of severe salt stress. On the other hand, biochar was more effective than F.mosseae in terms of soil pH and Ca/Na ratio. The results showed that biochar and F. mosseae were beneficial in reducing biotic ( V. dahliae) and abiotic stress (salt stress) damage while enhancing plant growth and nutrient absorption. Therefore, this study yields excellent and novel results, particularly in the field of employing beneficial microorganisms for sustainable agriculture.

Key messageA plant growth regulator, 5-aminolevulinic acid, enhanced the saline-alkali tolerance via photosynthetic, oxidative-reduction, and glutathione metabolism pathways in pepper seedlings.AbstractSaline-alkali stress is a prominent environmental problem, hindering growth and development of pepper. 5-Aminolevulinic acid (ALA) application effectively improves plant growth status under various abiotic stresses. Here, we evaluated morphological, physiological, and transcriptomic differences in saline-alkali-stressed pepper seedlings after ALA application to explore the impact of ALA on saline-alkali stress. The results indicated that saline-alkali stress inhibited plant growth, decreased biomass and photosynthesis, altered the osmolyte content and antioxidant system, and increased reactive oxygen species (ROS) accumulation and proline content in pepper seedlings. Conversely, the application of exogenous ALA alleviated this damage by increasing the photosynthetic rate, osmolyte content, antioxidant enzyme activity, and antioxidants, including superoxide dismutase, catalase, glutathione reductase, and glutathione peroxidase, and reducing glutathione to reduce ROS accumulation and malonaldehyde content. Moreover, the transcriptomic analysis revealed the differentially expressed genes were mainly associated with photosynthesis, oxidation-reduction process, and glutathione metabolism in saline-alkali stress + ALA treatment compared to saline-alkali treatment. Among them, the change in expression level in CaGST, CaGR, and CaGPX was close to the variation of corresponding enzyme activity. Collectively, our findings revealed the alleviating effect of ALA on saline-alkali stress in pepper seedlings, broadening the application of ALA and providing a feasible strategy for utilize saline-alkali soil.

Phytophthora, one among the most devastating phytopathogenic genus representing the oomycetes inflicts substantial damage to a broad spectrum of economically important horticultural crops worldwide. The rapid dissemination of Phytophthora in agro-ecosystems is mediated through bi-flagellated zoospores and their homing response towards the host is profoundly influenced by chemo-electrotactic mechanisms leading to encystment and subsequent colonization. Though different procedures are reported to isolate Phytophthora from infested rhizospheric soils, studies addressing zoospore encystment-based method using different baits for isolation and subsequent retrieval of cultures (in case of bacterial contamination) are meagre in Phytophthora-black pepper host-pathosystem. In the present study, Phytophthora was isolated from infested rhizospheric soils of black pepper using different baits viz., thermocol, impregnated paper discs, leaves of Albizzia falcataria and green gram roots. Modified cabin-sequestering methods were subsequently adopted to salvage the cultures in case of bacterial contamination, if any. The zoospore encystment-based method is cost effective and consumes lesser time for isolation of Phytophthora from infested rhizospheric soils of black pepper. Further, the two approaches of cabin sequestering method which were found promising in obtaining pure cultures of Phytophthora devoid of bacterial contamination, can also be employed to retrieve bacterial contaminated cultures of research significance.

In recent years, the fungal disease 'pepper stem rot', contracted from the soil -borne pathogen sclerotium rolfsii, has been increasing year by year, causing significant losses to the pepper (Capsicum annuum L.) industry. To investigate the infection mechanism of stem rot, the fungus S. rolfsii was used to infect the roots of pepper plants, and was found to affect root morphology and reduce root activity, which subsequently inhibited root growth and development. With fungal infestation, its secretions (oxalic acid, PG and PMG enzyme) were able to break normal tissues in the stem base and induced the burst of the active oxygen, which leads to injury aggravation. Morphological observations of the site of damage at the base of the stem using SEM revealed that the vascular bundles and stomata were completely blocked by hyphae, resulting in a blockade of material exchange in the plant. It was subsequently found that most of the stomata in the leaves were closed, which caused the leaves to lose their ability to photosynthesize, then turned yellow, wilt, shed, and the plant died. Commercialized fungicide thifluzamide with excellent in vitro (EC50 = 0.1 mu g/mL) and in vivo curative (EC50 = 29.2 mu g/mL) antifungal activity was selected to control the stem rot disease in peppers. The results demonstrated that it was able to suppress the secretion of associated pathogenic factors and reduce the outbursts of reactive oxygen species, thus reducing the damage caused by S. rolfsii at the base of the plant's stem and also enhancing the root activity of the infected plant, thereby promoting root growth. It could also inhibit fungal growth, unblock the vascular bundles and stomata, maintain a balance of material and energy exchange within the plant, and thus restore the damaged plant to its normal growth capacity. All the results will provide an adequate reference for the prevention and control of stem rot disease on peppers with thifluzamide.

PECTOBACTERIUM and Dickeya species are the main causative agents for soft rot disease that adversely affect fruits and vegetables leading to considerable economic losses. Biological management with beneficial microorganisms is a promising alternative to hazardous bactericides. Therefore, the antagonistic activity of two different strains of Rahnella aquatilis was in vitro and in vivo evaluated against nine soft rotting bacterial strains. The antagonistic soil bacteria R. aquatilis strains 17 and 55 restricted the growth of nine soft rotting bacterial strains on nutrient agar plates, (7 Pectobaterium carotovorum strains and 2 Dickeya chrysanthmi strains). Transmission electron micrographs of P. carotovorum Pep3B cells antagonized with R. aquatilis strain 17, showed damaged cells with disrupted plasma membrane releasing the cellular contents. To examine whether R. aquatilis 17 could be an effective biological control agent for pepper soft rot disease, two applications were conducted. The pepper seedlings were pretreated, before the pathogen, with R. aquatilis 17 through leaves and roots. All seedlings pretreated with the antagonistic strain 17 showed reduced susceptibility towards the P. carotovorum Pep3B, increased fresh, dry weights and seedlings' height relative to controls. R. aquatilis 17 inoculation has positively influenced the physiological parameters evaluated, such as chlorophyll content, carotenoids, phenolics, flavonoids, protein concentration as well as proline concentration. The obtained results revealed that R. aquatilis 17 mitigated the effect of P. carotovorum on pepper seedlings and promoted their growth, which means that it has a high probability of being an effective biological control agent and a plant-promoting bacterium.