Molecular Pathogens, 2025, Vol.16, No.6, 276-284 http://microbescipublisher.com/index.php/mp 278 3.2 Shifts in pathogen communities across different salinity gradients In fact, the composition of pathogenic bacteria is not static; it is closely related to changes in soil conditions. Agronomic measures such as no-tillage and straw returning to the field seem to be good ways to protect the soil, but they may also "unintentionally" increase the numbers of Fusarium glutinale and Fusarium stramineum, thereby increasing the risk of diseases (Wang et al., 2020). If corn is planted year after year and the environmental pressure is also high, the more pathogenic Fusarium and Trichoderma will be more likely to gain the upper hand. Once the proportion of beneficial bacteria and protective bacteria decreases, the resistance of corn will naturally become weak. Although there is not much direct evidence on the impact of salinity gradient on pathogenic bacteria at present, existing studies have suggested that stresses such as salinization are likely to make resilient and more toxic pathogens more prone to spread (Zhao et al., 2021). 3.3 Salt-induced changes in pathogen virulence, metabolism, and survival strategies Not all pathogenic bacteria will "fail" in a saline-alkali environment. Fusarium verticillioides is an exception. It can form tight biofilms and thereby enhance its survival ability under extreme pH and temperature conditions (Peremore et al., 2025). Biofilms offer not only a protective shell, but also mean more flexible metabolism and stronger adaptability. For it, saline-alkali soil might instead become a "suitable breeding ground for survival". This also makes prevention and control more difficult. A pathogen that can adapt to high salt and enhance its virulence is clearly more threatening. Such physiological changes remind us that understanding the ecological strategies of pathogenic bacteria in a saline-alkali background is not only a scientific research issue but also a key point in practical prevention and control (Wang et al., 2020). 4 Maize Physiological and Immune Responses under Saline–Alkaline Conditions 4.1 Effects of salt stress on maize root structure and physiological metabolism Once a saline-alkali environment is formed, the root system of corn is the first to be impacted. Some strains show particularly obvious reactions. For instance, root cells are severely damaged, reactive oxygen species (ROS) levels rise significantly, and electrolytes start to leak in large quantities, making the entire root system appear very fragile. Salt-tolerant corn is different. Their roots can still maintain good integrity, and the levels of osmotic regulatory substances (such as soluble sugars and flavonoids) in their bodies are relatively high, and antioxidant enzymes are also active (Fatima et al., 2021). However, regardless of the variety, the accumulation of salt will disrupt the absorption of nutrients by the roots, especially the decrease of potassium and the increase of sodium, which can easily lead to the instability of cell membranes, and the vitality of the entire corn plant will naturally decline (Figure 1) (Ullah et al., 2025). 4.2 Influence of salinization on maize defense gene expression and immune-related pathways Under saline-alkali stress, some key resistance pathways in corn will "activate", but the situation is not always singular. For instance, the two transcription factors, ZmWRKY82 and ZmNAC89, will be activated. They promote the synthesis of flavonoids and help plants enhance their antioxidant capacity (Hu et al., 2023; Wang et al., 2025). Meanwhile, multiple pathways involved in hormone signaling (especially ABA), MAPK, and REDOX reactions will also experience changes in gene expression levels. The activation of these pathways helps enhance the environmental adaptability of corn. However, it should be noted that sometimes certain defense paths may also be suppressed, and regulation is not enhanced across the board. In addition, chitinase genes like LcCHI2 can simultaneously endow corn with dual resistance to pathogens and salt damage, which is particularly crucial in specific contexts (Li, 2025). 4.3 Interactions between salt stress and pathogen infection (salt–disease interaction model) Not all stresses occur in a single line; salt damage and diseases often come together. Especially in plots with a high risk of root rot, once salinization intensifies, the damage caused by pathogenic bacteria will also be more difficult to control. However, some salt-tolerant strains have demonstrated decent "dual resistance" capabilities. Through enhanced antioxidant mechanisms and osmotic regulation systems, they have suppressed the dual pressures brought by salt damage and pathogen invasion (Zhao et al., 2025). Moreover, when genes like chitinase
RkJQdWJsaXNoZXIy MjQ4ODYzNA==