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BACKGROUND: The complete mitochondrial respiratory chain is a precondition for maintaining cellular energy supply, development, and metabolic balance. Due to the evolutionary differentiation of complexes and the semi-autonomy of mitochondria, respiratory chain subunits have become critical targets for crop improvement and fungal control. In fungi, mitochondrial complex I mediates growth and metabolism. However, the role of this complex in the pathogenesis of phytopathogenic fungi is largely unknown. RESULTS: In this study, we identified the NADH: ubiquinone oxidoreductase 24-kDa subunit (VdNuo1) of complex in vascular wilt pathogen, Verticillium dahliae, and examined its functional conservation in phytopathogenic fungi. Based on the treatments with respiratory chain inhibitors, the mitochondria-localized VdNuo1 was confirmed to regulate mitochondrial morphogenesis and homeostasis. VdNuo1 was induced during the different developmental stages in V. dahliae, including hyphal growth, conidiation, and melanized microsclerotia development. The VdNuo1 mutants displayed variable sensitivity to stress factors and decreased pathogenicity in multiple hosts, indicating that VdNuo1 is necessary in stress tolerance and full virulence. Comparative transcriptome analysis demonstrated that VdNuo1 mediates global transcriptional effects, including oxidation and reduction processes, fatty acid, sugar, and energy metabolism. These defects are partly attributed to impairments of mitochondrial morphological integrity, complex assembly, and related functions. Its homologue (CgNuo1) functions in the vegetative growth, melanin biosynthesis, and pathogenicity of Colletotrichum gloeosporioides; however, CgNuo1 does not restore the VdNuo1 mutant to normal phenotypes. CONCLUSIONS: Our results revealed that VdNuo1 plays important roles in growth, metabolism, microsclerotia development, stress tolerance, and virulence of V. dahliae, sharing novel insight into the function of complex I and a potential fungicide target for pathogenic fungi.

RESEARCH HIGHLIGHTSAvian pathogenic Escherichia coli (APEC) is an important zoonotic pathogen that infects avian species by colonizing the gastrointestinal, respiratory, or reproductive tracts, leading to significant economic losses to the poultry industry worldwide and threatening food security and human health. APEC has evolved the two-component signal transduction system (TCS) to adapt and respond to extracellular environmental stresses, which are produced when the host is invaded by APEC. Here, we focus on the effect of the UhpAB TCS on the pathogenicity of APEC. The results in this study showed that the UhpAB TCS contributed to the pathogenicity of APEC in a chicken infection model. The electrophoretic mobility shift assays (EMSA) confirmed that UhpAB specifically bound to the promoters of fepG, ldrD, ycgV, and ydeI, and activated their expression, measured using real-time reverse transcription PCR (real-time RT–PCR). Furthermore, the UhpAB TCS could promote biofilm formation by activating the expression of biofilm master transcriptional regulator encoding gene csgD and enhance stress tolerance by activating the expression of stress protein encoding genes uspA and bhsA, thereby assisting APEC to evade host immune responses and inflammatory responses, and increasing the pathogenicity of APEC. These findings deepen our understanding of the pathogenic mechanism in APEC and offer new perspectives for further studies on the prevention and control of APEC infection.UhpAB increases the pathogenicity of APEC.UhpAB activates the expression of virulence genes fepG, ldrD, ycgV, and ydeI.UhpAB promotes biofilm formation and enhances stress tolerance.UhpAB contributes to APEC evading attack by the host immune system.UhpAB increases the pathogenicity of APEC.UhpAB activates the expression of virulence genes fepG, ldrD, ycgV, and ydeI.UhpAB promotes biofilm formation and enhances stress tolerance.UhpAB contributes to APEC evading attack by the host immune system. [ABSTRACT FROM AUTHOR]

Grass endophytes (Epichloë) are important symbiotic microorganisms of perennial ryegrass, playing a vital role in plant resistance against various stresses. This study investigated the effects of grass endophyte on leaf spot disease caused by fungal pathogen Bipolaris sorokiniana and subsequent feeding preferences of aphids (Rhopalosiphum maidis) on perennial ryegrass, with a particular focus on how grass endophyte influence the interactions between pathogens and aphids. The results indicated that grass endophytes significantly increased the net photosynthetic efficiency of perennial ryegrass. The interactions among grass endophytes, pathogen, and aphids affected the activities of superoxide dismutase (SOD), peroxidases (POD), and catalase (CAT). Grass endophytes enhanced SOD and CAT activities in pathogen-infected ryegrass. While pathogen infection and aphid infestation decreased jasmonic acid (JA) and salicylic acid (SA) concentrations, grass endophyte increased SA levels. Correlation analysis revealed a negative relationship between shoot dry weight and plant transpiration rate, SOD, and CAT activities. Aphid feeding choice showed that grass endophytes attracted more aphid feeding when co-infected with pathogens. This preference correlated positively with H2O2 and SA levels but negatively with NO and JA concentrations. Overall, grass endophytes enhance perennial ryegrass resistance to leaf spot pathogens and aphids, offering a novel pest and disease management strategy in agriculture. [ABSTRACT FROM AUTHOR]

Tomato (Solanum lycopersicum), which is considered one of the more important and widely cultivated crop members of the family Solanaceae, exhibits numerous biochemical mechanisms to alleviate the stress produced by various biotic and abiotic factors. Many researchers have found that phytochelatins (PCs) play an important role in these stress-alleviating mechanisms and, therefore, contribute significantly to the plant's coping strategies, particularly under heavy metal exposure. Ongoing research has extensively investigated tomato genotypes in plant stress research, with a particular focus on heavy metal stress. The production of PCs, synthesized from glutathione, is regulated by various factors and different stressors. Here, we aim to provide an overview of the panorama regarding the synthesis of PCs in tomato under different environmental conditions and experimental settings, as well as provide information on their broader roles in biotechnology and modulating plant tolerance and responses across diverse stress conditions and treatments within the context of tomato research. [ABSTRACT FROM AUTHOR]

Limited aerobic scope (AS) during digestion might be the main constraint on the performance of bodily functions in water‐breathing animals. Thus, investigating the postprandial changes in various physiological functions and determining the existence of a shared common pattern because of possible dependence on residual AS during digestion in freshwater fish species are very important in conservation physiology. All species from slow‐flow habitats showed impaired swimming speed while digesting, whereas all species from fast‐flow habitats showed strong swimming performance, which was unchanged while digesting. Only two species from slow‐flow habitats showed impaired heat tolerance during digestion, suggesting that whether oxygen limitation is involved in the heat tolerance process is species‐specific. Three species from slow‐ or intermediate‐flow habitats showed impaired hypoxia tolerance during digestion because feeding metabolism cannot cease completely under hypoxia. Overall, there was no common pattern in postprandial changes in different physiological functions because: (1) the digestion process was suppressed under oxygen‐limiting conditions, (2) the residual AS decreased during digestion, and (3) performance was related to residual AS, while digestion was context‐dependent and species‐specific. However, digestion generally showed a stronger effect on bodily functions in species from slow‐flow habitats, whereas it showed no impairment in fishes from fast‐flow habitats. Nevertheless, the postprandial change in physiological functions varies with habitat, possibly due to divergent selective pressure on such functions. More importantly, the present study suggests that a precise prediction of how freshwater fish populations will respond to global climate change needs to incorporate data from postprandial fishes. [ABSTRACT FROM AUTHOR]

Polyploid varieties have been suggested as an alternative approach to promote drought tolerance in citrus crops. In this study, we compared the responses of diploid and tetraploid Sunki 'Tropical' rootstocks to water deficit when grafted onto 'Valencia' sweet orange trees and subjected to water withholding in isolation or competition experiments under potted conditions. Our results revealed that, when grown in isolation, tetraploid rootstocks took longer to show drought symptoms, but this advantage disappeared when grown in competition under the same soil moisture conditions. The differences in drought responses were mainly associated with variations in endogenous leaf levels of abscisic acid (ABA), hydrogen peroxide (H₂O₂) and carbohydrates among treatments. Overall, tetraploids were more affected by drought in individual experiments, showing higher H₂O₂ production, and in competition experiments, rapidly increasing ABA production to regulate stomatal closure and reduce water loss through transpiration. Therefore, our results highlight the crucial importance of evaluating diploid and tetraploid rootstocks under the same soil moisture conditions to better simulate field conditions, providing important insights to improve selection strategies for more resilient citrus rootstocks. Summary statement: This study investigates the drought responses of diploid and tetraploid Sunki 'Tropical' rootstocks grafted onto sweet oranges 'Valencia'. Tetraploids initially showed delayed drought symptoms when considered in isolation; however, this advantage was lost under competitive conditions. Variations in abscisic acid (ABA), hydrogen peroxide (H₂O₂) and carbohydrates played a crucial role in these responses. Notably, although tetraploids exhibited an initial advantage, they displayed greater sensitivity to drought under conditions that more closely mimic field environments. These findings challenge the widely accepted notion that tetraploids are inherently more drought‐tolerant than diploids, indicating the need for more detailed and realistic evaluations to improve drought resilience in citrus rootstocks. [ABSTRACT FROM AUTHOR]

The growing demand for food production and increasing stress scenarios increase the crucial need for sustainable alternatives to achieve increased crop yield and quality without affecting the environment. The use of brown macroalgae, being a renewable resource, is a promising option with various application options in agricultural systems, mainly in the form of extracts, direct applications, and compost. Brown algae are a source of active biomolecules and minerals that are currently used as agricultural biostimulants, since they increase crop productivity. This type of biostimulants derived from brown algae improve seed germination, increase the accumulation of plant biomass by accelerating cell division and elongation, activating the antioxidant system of plants, making them more resistant to stress, and contributes to the absorption and translocation of nutrients present in the soil. These products are also compatible with other agricultural inputs, such as synthetic fertilizers and pesticides, which makes them ideal for comprehensive applications and maintaining a balance in agroecosystems. This review incorporates fundamental and applied aspects of brown seaweeds that impact yields, biochemical quality, physiology, stress mitigation, and soil properties. Based on the above, the review is divided into different Sections that show the formulation of brown seaweed products; their effect on crop yield, quality, and physiology; their effect on biotic and abiotic stress mitigation; and their impact on soil physical, chemical, and biological properties. [ABSTRACT FROM AUTHOR]

Plants are frequently challenged by a variety of microorganisms. To protect themselves against harmful invaders, they have evolved highly effective defense mechanisms, including the synthesis of numerous types of antimicrobial peptides (AMPs). Snakins are such compounds, encoded by the GASA (Gibberellic Acid-Stimulated Arabidopsis) gene family, and are involved in the response to biotic and abiotic stress. Here, we examined the function of the newly identified TdGASA1 gene and its encoded protein in Triticum durum subjected to different biotic stress-related simulants, such as mechanical injury, methyl jasmonate (MeJA), indole-3-acetic acid (IAA), salicylic acid (SA), hydrogen peroxide (H2O2), as well as infection with pathogenic fungi Fusarium graminearum and Aspergillus niger. We found that in durum wheat, TdGASA1 transcripts were markedly increased in response to these stress simulants. Isolated and purified TdGASA1 protein exhibited significant antifungal activity in the growth inhibition test conducted on eight species of pathogenic fungi on solid and liquid media. Transgenic Arabidopsis lines overexpressing TdGASA1 obtained in this study showed higher tolerance to detrimental effects of H2O2, MeJA, and ABA treatment. In addition, these lines exhibited resistance to Fusarium graminearum and Aspergillus niger, which was linked to a marked increase in antioxidant activity in the leaves under stress conditions. This resistance was correlated with the upregulation of pathogenesis-related genes (AtPDF1.2a, AtERF1, AtVSP2, AtMYC2, AtPR1, AtACS6, AtETR1, and AtLOX2) in the transgenic lines. Overall, our results indicate that TdGASA1 gene and its encoded protein respond ubiquitously to a range of biotic stimuli and seem to be crucial for the basal resistance of plants against pathogenic fungi. This gene could therefore be a valuable target for genetic engineering to enhance wheat resistance to biotic stress. [ABSTRACT FROM AUTHOR]

This study evaluates the stress tolerance and metabolic adaptability of twelve yeast strains, including eleven commercial strains from Wyeast Laboratories and one prototrophic laboratory strain, under industrially relevant conditions. Yeast strains were assessed for their fermentation performance and stress responses under glucose limitation, osmotic stress, acid stress, elevated ethanol concentrations, and temperature fluctuations. Results revealed significant variability in glucose consumption, ethanol production, and stress tolerance across strains. ACY34 and ACY84 demonstrated the highest fermentation efficiency, while ACY19 exhibited exceptional stress resilience, excelling under multiple stress conditions such as osmotic and ethanol stress. The findings highlight strain-specific performance, with some strains suited for high-yield fermentation and others excelling under challenging environmental conditions. These results provide critical insights for selecting and optimizing yeast strains tailored to specific industrial fermentation processes, contributing to improved productivity and product quality in food and beverage production. [ABSTRACT FROM AUTHOR]