Zinc thiazole enhances defense enzyme activities and increases pathogen resistance to Ralstonia solanacearum in peanut (Arachis hypogaea) under salt stress

Abstract

Crop plants always encounter multiple stresses in the natural environment. Here, the effects of the fungicide zinc thiazole (ZT) on propagation of Ralstonia solanacearum, a bacterial pathogen, were investigated in peanut seedlings under salt stress. Compared with water control, salt stress markedly reduced pathogen resistance in peanut seedlings. However, impaired pathogen resistance was alleviated by treatment with dimethylthiourea, a specific ROS scavenger, or ZT. Subsequently, salt stress or combined salt and pathogen treatment resulted in inhibition of photosynthesis, loss of chlorophyll and accumulation of thiobarbituric acid reactive substances, which could be reversed by ZT. In addition, ZT treatment suppressed the salt stress up-regulated Na+ content and Na+/K+ ratios in peanut roots. Furthermore, salt stress or combined salt and pathogen treatment impaired the activities of antioxidant (e.g. superoxide dismutase/SOD and catalase/CAT), and defense-related (e.g. phenylalanine ammonia lyase /PAL and polyphenol oxidase/PPO) enzymes, which could be rescued by addition of ZT. In contrast, only slight changes of SOD and CAT activities were observed in pathogen-infected seedlings. Similarly, activities of PAL and PPO were slightly modified by salt stress in peanut seedlings. These results suggest that the ZT-enhanced pathogen resistance can be partly attributed to the improvement of photosynthetic capacity and defense enzyme activities, and also the inhibition of Na+/K+ ratios, in this salt-stressed crop plant.

Isolation and identification of symbiotic strains in Paris fargesii Franch that promote disease resistance

“…Symbiotic strains can promote plant growth through direct and indirect mechanisms (Glick, 1995): direct mechanisms are manifested in the ability of the strain to promote nutrient uptake by the host plant through its own nitrogen fixation (Peŕez-Montaño et al, 2014), phosphate solubilization (Alori et al, 2017), potassium solubilization (Zhang et al, 2020) and other probiotic characteristics, providing vitamins needed for plant growth, and through the production of growth hormone-like phytohormones (Ahmed and Hasnain, 2010;Wagi and Ahmed, 2019) similar to the phytohhormones of the host plant. A symbiotic strain also promotes the accumulation of active substances in the host plant by producing some physiologically active metabolites that are the same as or similar to the metabolites of the host plant, such as paclitaxel (Stierle et al, 1993), podophyllotoxin (Eyberger et al, 2006), camptothecin (Kusari et al, 2009), huperzine (Li et al, 2007) and quercetin (Min et al, 2010); the indirect mechanism is manifested mainly in the ability of symbiotic strains to directly inhibit the growth of pathogenic bacteria (Zhang et al, 2017) and to enhance host plant biocontrol enzymes such as polyphenol oxidase (PPO), phenylalanine aminolase (PAL), superoxide dismutase (SOD) and peroxidase (POD) active enzymes (Sang et al, 2019) and the expression of related resistance genes (Sherameti et al, 2005), thus indirectly promoting plant growth.…”

Response of salt stress resistance in highland barley (Hordeum vulgare L. var. nudum) through phenylpropane metabolic pathway

“…PAL is the first reactive enzyme in the phenylpropane metabolism pathway, and also a rate-limiting enzyme in catalyzing phenylpropane to cinnamic acid, which is the precursor for the synthesis of downstream secondary metabolites [42]. Sang [43] found that the PAL activity was increased in wheat roots…”

Effects of Zinc Thiazole and Oxytetracycline on the Microbial Metabolism, Antibiotic Resistance, and Virulence Factor Genes of Soil, Earthworm Gut, and Phyllosphere

“…14 However, being a systemic and less degradable fungicide, zinc thiazole can persist in soil environments for a long time, ultimately affecting soil microbial activity. 15 In addition, antibiotics are applied worldwide to veterinary medicines. Unfortunately, large amounts of antibiotics are not assimilated by organisms and are excreted via organic manure into agricultural fields.…”

“…Growing evidence showed that pesticide residues in soils have an important selective pressure of ARGs. , Zinc thiazole (2-amino-5-mercapto-1,3,4-thiadiazole zinc) is widely used to control bacterial diseases in crops . However, being a systemic and less degradable fungicide, zinc thiazole can persist in soil environments for a long time, ultimately affecting soil microbial activity . In addition, antibiotics are applied worldwide to veterinary medicines.…”