Shahram Naeimi

This study evaluated the effects of Exiguobacterium aurantiacum SA100 on wheat (Triticum aestivum) growth under varying levels of salinity stress. Results indicated that SA100 significantly enhanced seed germination, root and shoot length, and fresh and dry biomass across salinity levels, particularly at 50 and 100 mM NaCl. Inoculation improved antioxidant enzyme activities (CAT, APX, POD, PPO), increased total phenolic content, and reduced oxidative damage by lowering MDA and H₂O₂ levels under 150 mM salinity. Ionic balance was maintained, with significant increases in K⁺, Mg⁺⁺, and Ca⁺⁺ and a reduction in Na⁺ accumulation. Gene expression analysis revealed upregulation of salt‐tolerance genes (NAC7, NHX1, SOS1) and downregulation of stress‐responsive genes (GS1, DREB2, DHN13, WRKY32). Principal component analysis confirmed that SA100 promotes salinity tolerance by modulating both biochemical and molecular responses. These findings suggest E. aurantiacum SA100 as a promising bioinoculant for enhancing wheat resilience under salinity stress.

Salinity stress severely impacts wheat productivity, necessitating effective strategies to enhance crop resilience. This study investigates the potential of Penicillium chrysogenum CM022 as a biological agent to alleviate the impact of salinity stress on wheat (Triticum aestivum L.). P. chrysogenum CM022 improved germination of wheat seeds, particularly under salinity of 150 mM NaCl. Fungal inoculation significantly improved plant growth in terms of root length, plant height, and seedling biomass, even under high salinity conditions. Notably, inoculated plants preserved photosynthetic pigments and reduced oxidative damage, evidenced by lower levels of hydrogen peroxide (H₂O₂) and malondialdehyde (MDA), compared to non-inoculated controls. The inoculated plants also exhibited enhanced proline and soluble sugar contents, which are crucial for osmotic adjustment under stress. Additionally, P. chrysogenum CM022 significantly increased the antioxidant capacity of wheat, boosting total phenolic and flavonoid contents, and enhancing antioxidant enzyme activity under high salinity. These findings underscore the potential of P. chrysogenum CM022 in improving wheat tolerance to salinity stress through physiological, biochemical, and antioxidant defense mechanisms, supporting its use in sustainable agricultural practices to mitigate the adverse effects of salinity on crop production.

Strengthening agriculture is crucial for ensuring food security for the world’s expanding population. Endophytes, microorganisms that live within plant tissues without harming the host, can colonize these tissues. They promote plant growth, serve as biocontrol agents, and naturally shield the host from a variety of biotic and abiotic challenges. Each year, the emergence of numerous stresses in crops leads to a decrease in yield, resulting in significant losses. To mitigate these losses and manage plant pests and diseases, various effective strategies should be employed. Endophytes, being environmentally friendly, non-toxic, and cost-effective, could serve as an alternative for farmers aiming for sustainable agriculture. This chapter will discuss the biochemical, molecular, and genetic mechanisms of endophytes in enhancing stress tolerance in different crops and their role as biological control agents. Furthermore, endophytes and their metabolites should be explored as potential beneficial agents in the biological control of plant pests and diseases, extending the investigation up to the multi-omics level.

Plant Growth-Promoting Rhizobacteria (PGPR) modifies the activity of the relevant genes to affect the physiological traits, metabolites, pathways, and proteins of plants. Traditional methods for creating salt-tolerant crops are expensive, laborious, and occasionally difficult to adopt. It has been proposed that using microorganisms that encourage plant growth is a suitable and economical method of raising plant tolerance. These evocative microbes can act as a mediator between plants and their morphological, physiological, and molecular responses. Extensive research has been done on the signaling pathways used by hormones, plant receptors, and microbial signals to stimulate PGPR in plants. This chapter aims to increase comprehension of the convergence mechanisms used by these signaling molecules as well as the ambiguities of signaling activities that occur in the host as a result of interactions with PGPR under demanding environmental situations. In order to address biotic and abiotic stressors in agricultural areas and hence raise global food production, the use of rhizobacteria inoculants is a viable strategy.

Plant disease outbreaks are increasingly exacerbated by climate change and the conditions of stress combinations. They are negatively affecting crop yield and driving threats to food security in many areas of the world. Although synthetic pesticides offer relative success in the control of pests and plant diseases, they are often overused, and this method faces numerous drawbacks, including environmental toxicity, soil degradation, and adverse effects on human health. Therefore, alternatives are being developed and examined, including the biocontrol of pests and pathogens and biomass pyrolysis leading to wood vinegar that has shown great promise in agriculture and organic farming. However, while wood vinegar use is expanding and allows the control of numerous pests and bacterial and fungal diseases, its application to control oomycete diseases is limited. This study aimed to test wood vinegar for the control of oomycete plant pathogens from which six wood vinegars of pistachio, pomegranate, almond, pine, cypress, and walnut were produced. The inhibitory effects of volatile metabolites (semi-VOCs) of different wood vinegars concentrations (100%, 50%, 25%, 12.5%, and 6.25%) were examined against the hyphal growth of Globisporangium ultimum and Pythium aphanidermatum isolates. An in vitro analysis unambiguously demonstrated that for Globisporangium ultimum, the wood vinegar semi-VOCs of almond, pistachio (C 100% and 50%), and walnut (C 100%) totally inhibited mycelial growth. On the other hand, Pythium aphanidermatum, pistachio (C 100%, 50%, and 25%), and cypress (C 100%) expressed their abilities to completely inhibit the mycelial growth. Other treatments, including relevant concentrations of pine and pomegranate significantly inhibited the growth of mycelia of both species compared to the control (p ≤ 0.05). Therefore, wood vinegar could be considered a natural and organic product to use in agriculture to cope not only against pests, bacterial and fungal pests but also against emerging oomycete plant diseases.

Crop diseases and agricultural pests and pathogens are causing huge economic losses. The actual means for dealing with them involve the use of damaging chemical pesticides that harm the environment, threaten biodiversity, and undermine human health. This research was aimed at developing an environmentally friendly means to cope with emerging oomycete disease from tomato fields in the province of East-Azerbaijan. The oomycete disease causal agent was isolated and identified as Ovatisporangium sp. using a combination of morphological features and molecular methods. Six wood vinegars (pyroligneous acid) belonging to pine, pomegranate, pistachio, almond, walnut, and cypress were produced during this study and examined against Ovatisporangium sp. Their inhibition of volatile metabolites (VOCs) using different dilutions (1, 1/2, 1/4, 1/8, and 1/10) was assessed against the mycelial growth of Ovatisporangium sp. In vitro analysis demonstrated that pistachio, cypress, and almond dilution 1 (D 1) wood vinegar VOCs had the ability to stop the mycelial growth of Ovatisporangium sp. All other treatments including pine, walnut, and pomegranate with relevant dilutions significantly reduced the mycelial growth of Ovatisporangium sp. compared with the control (p ≤ 0.05). Wood vinegar is therefore a potent means to cope with pathogenic infections and allows plant protection against oomycete diseases.