Abiotic and biotic stresses, such as mineral nutrition deficiency (especially nitrogen) and Fusarium attack, pose a global threat with devastating impact on wheat yield and quality losses worldwide. This preliminary study aimed to determine the effect of Fusarium inoculation and two different nitrogen levels on oxidative status and antioxidative response in nine wheat varieties. Level of lipid peroxidation, activities of antioxidant enzymes (catalase, ascorbate peroxidase, glutathione reductase), phenolics, and chloroplast pigments content were measured. In general, wheat variety, nitrogen, and Fusarium treatment had an impact on all tested parameters. The most significant effect had a low nitrogen level itself, which mostly decreased activities of all antioxidant enzymes and reduced the chloroplast pigment content. At low nitrogen level, Fusarium treatment increased activities of some antioxidative enzymes, while in a condition of high nitrogen levels, antioxidative enzyme activities were mostly decreased due to Fusarium treatment. The obtained results provided a better understanding on wheat defense mechanisms against F. culmorum, under different nitrogen treatments and can serve as an additional tool in assessing wheat tolerance to various environmental stress conditions.

Fusarium head blight and inadequate nitrogen fertilization can cause numerous biochemical changes in wheat. The main aim of this study was to determine the effects of Fusarium inoculation and a broader range of different nitrogen fertilization on the defense response in the spikes of four wheat varieties, varying in FHB susceptibility. Total soluble phenolics content, activities of enzymes involved in phenol metabolism (PAL and PPO), and total antioxidant capacity were determined as indicators of defense response. In both growing seasons, Fusarium inoculation altered PHE content in wheat spikes, indicating involvement of PHE in the defense response to Fusarium attack. Increased PHE content in the partially resistant varieties (Apache and Graindor) indicates involvement of PHE in the defense response and better disease tolerance in the more resistant varieties. Breeding wheat varieties with enhanced PHE synthesis could be a promising strategy to control FHB. To the best of our knowledge, this is the first study that emphasizes the effects of Fusarium infection and a broader range of different nitrogen fertilization on PHE and enzymes involved in PHE metabolism. In addition, this is the first study using the FRAP method to determine the antioxidant capacity of wheat tissues under the influence of Fusarium infection and different nitrogen fertilization.

Selenium (Se) deficiency in human and animal nutrition is primarily due to low levels of Se in soils. It can be prevented by enriching crops, such as wheat, with Se through agronomic biofortification. Although Se is not essential for plants, it shows a dual effect on their metabolism depending on its concentration. This study aimed to elucidate the impact of five different concentrations (0.4, 4, 20, 40, and 400 mg/kg) of selenate and selenite on the oxidative status and antioxidative response of wheat (Triticum aestivum L., cv. Kraljica) shoots and roots. According to morpho-physiological analyses, selenite was found to have a lower toxicity threshold than selenate. The measurement of oxidative stress biomarkers showed that Se did not cause oxidative damage to wheat seedlings due to the activation of detoxification mechanisms at the biochemical level, which depended on the type of tissue, concentration, and form of applied Se. Treatment with 20 mg/kg of selenate can be recommended for wheat seedling biofortification due to a sufficient increase in Se accumulation in shoots without signs of toxicity. These results contribute to a better understanding of wheat seedlings’ physiological and biochemical responses to Se and the development of more effective biofortification strategies.

Fuzarijska palež klasova (FHB) pšenice ekonomski je značajna bolest koja može imati nepovoljne posljedice na prinos i kvalitetu pšenice. Do danas ne postoji mjera zaštite koja osigurava potpunu zaštitu usjeva pšenice, ali kombinacija više mjera može dati dobre rezultate. Učinkovitost svake pojedine mjere pod utjecajem je okolišnih uvjeta koji prevladavaju tijekom vegetacijske sezone, a učinkovitost će ovisiti i o osjetljivosti pojedine sorte na FHB. Sve veći broj istraživanja potvrđuje kako je integrirana zaštita bilja (IZB) ključ za što uspješniju borbu protiv FHB-a. Kako bi primijenjene mjere zaštite bile što uspješnije, od iznimne je važnosti dobro poznavati uzročnika bolesti, njegov životni ciklus i ekologiju. Budući da je F. graminearum dominantni uzročnik FHB-a na području Republike Hrvatske, osobiti naglasak je stavljen na sve dostupne mjere zaštite u njegovu suzbijanju.

Zbog stalnog povećanja upotrebe kemijskih pesticida i njihovog štetnog djelovanja na ljudsko zdravlje i okoliš, sve veće zanimanje pobuđuju metode biološke kontrole uzročnika biljnih bolesti. Biološka kontrola je mjera koja podrazumijeva korištenje mikroorganizama koji smanjuju populaciju štetnika i patogena i na taj način štite biljku i kontroliraju razvoj bolesti. U Hrvatskoj je trenutno na tržištu prisutan samo jedan biofungicid, na bazi bakterije iz roda Pseudomonas, za suzbijanje uzročnika bijele noge (Rhizoctonia solani) na krumpiru, batatu, čičoki i kineskom jamu te uzročnika srebrolikosti gomolja (Helminthosporium solani) na krumpiru. Vrste Bacillus thuringiensis, Bacillus subtilis i Pseudomonas fluorescens su najvažniji predstavnici bakterija uključenih u biokontrolu protiv uzročnika biljnih bolesti. Do danas je na svjetskom tržištu prisutno ili je u procesu registracije 28 sredstava na bazi različitih vrsta roda Trichoderma, koji većinom djeluju protiv fitopatogenih gljiva iz rodova Pythium, Rhizoctonia i Fusarium. Najzastupljenije vrste roda Trichoderma koje se koriste u biološkoj kontroli su Trichoderma harzianum, Trichoderma viride i Trichoderma koningii. Upotreba antagonističkih gljiva i bakterija u biološkoj kontroli brojnih uzročnika bolesti predstavlja važnu alternativu kojom bi se mogli zamijeniti kemijski pesticidi ili u što većoj mjeri smanjiti njihova primjena. Cilj rada je prikazati antagonističke gljive i bakterije koje se koriste u biološkoj kontroli te opisati njihove složene mehanizme djelovanja.

Wheat production worldwide is significantly threatened by phytopathogenic fungi of the genus Fusarium, while inadequate nitrogen fertilization can contribute to the development of Fusarium head blight (FHB), ultimately leading to reduced yield and grain quality. This study aimed to elucidate the individual and interactive effects of genotype, Fusarium inoculation and different nitrogen treatments on the antioxidant response of wheat spikes across two growing seasons. The study was conducted under field conditions on four winter wheat genotypes differing in FHB susceptibility. Oxidative stress was assessed by lipid peroxidation, and antioxidant responses by glutathione content and antioxidant enzyme activities. The results showed that wheat antioxidant responses to Fusarium infection were mainly shaped by genotype and seasonal conditions, with significant genotype-dependent interactions with nitrogen supply. FHB-susceptible genotypes, Srpanjka and Sofru, showed consistently lower basal glutathione levels and glutathione S-transferase activity than the resistant genotypes Apache and Graindor in both growing seasons. In both seasons, Fusarium inoculation increased guaiacol peroxidase activity in most genotypes, suggesting a consistent association with infection response. These findings improve understanding of wheat defence responses under varying nitrogen levels and may support more effective FHB management. Overall, the results indicate that antioxidant responses reflect both defence activation and stress intensity, depending on genotype and environmental conditions.