Winter wheat lines were evaluated for their reaction to Fusarium head blight (FHB) after inoculation with Fusarium culmorum in two field experiments. A mixture of two F. culmorum chemotypes was applied (3ADON—deoxynivalenol producing, NIV—nivalenol producing). Different types of resistance were evaluated, including head infection, kernel damage, Fusarium biomass content and trichothecenes B (deoxynivalenol (DON), and nivalenol (NIV)) accumulation in grain. The aim of the study was to find relationships between different types of resistance. Head infection (FHB index) and Fusarium damaged kernels (FDK) were visually scored. Fusarium biomass was analysed using real-time PCR. Trichothecenes B accumulation was analysed using gas chromatography. Wheat lines differ in their reaction to inoculation for all parameters describing FHB resistance. We found a wide variability of FHB indexes, FDK, and Fusarium biomass content. Both toxins were present. DON content was about 60% higher than NIV and variability of this proportion between lines was observed. Significant correlation was found between head infection symptoms and FDK. Head infection was correlated with F. culmorum biomass and NIV concentration in grain. No correlation was found between the FHB index and DON concentration. Similarly, FDK was not correlated with DON content, but it was with NIV content; however, the coefficients were higher than for the FHB index. Fusarium biomass amount was positively correlated with both toxins as well as with the FHB index and FDK. Environmental conditions significantly influenced the DON/NIV ratio in grain. In locations where less F. culmorum biomass was detected, the DON amount was higher than NIV, while in locations where more F. culmorum biomass was observed, NIV prevailed over DON.

Fusarium head blight (FHB) can contaminate cereal grains with mycotoxins. Winter wheat can also become infected with FHB and is more resistant than durum wheat to head infection but less than other small-grain cereals. The aim of this study was to identify winter wheat lines that combine low levels of head infection and kernel damage with low levels of grain contamination with mycotoxins. Resistance of 27 winter wheat lines (four with resistance gene Fhb1) and cultivars to FHB was evaluated over a three-year (2017–2019) experiment established in two locations (Poznań and Radzików, Poland). At the anthesis stage, heads were inoculated with Fusarium culmorum isolates. The FHB index was scored, and the percentage of Fusarium-damaged kernels (FDKs) was assessed. The grain was analyzed for type B trichothecenes (deoxynivalenol and derivatives and nivalenol) and zearalenone content. The average FHB index of both locations was 12.9%. The proportion of FDK was 6.9% in weight and 8.5% in number. The average content of deoxynivalenol amounted to 3.543 mg/kg, and the average amount of nivalenol was 2.115 mg/kg. In total, we recorded 5.804 m/kg of type B trichothecenes. The zearalenone content in the grain was 0.214 mg/kg. Relationships between the FHB index, FDK, and mycotoxin contents were highly significant for wheat lines; however, these relationships were stronger for FDK than for FHB index. Breeding lines combining all types of FHB resistance were observed, five of which had resistance levels similar to those of wheat lines with the Fhb1 gene.

The cell wall emerged as one of the important structures in plant stress responses. To investigate the effect of cold on the cell wall properties, the content and localization of pectins and pectin methylesterase (PME) activity, were studied in two maize inbred lines characterized by different sensitivity to cold. Low temperature (14/12 °C) caused a reduction of pectin content and PME activity in leaves of chilling-sensitive maize line, especially after prolonged treatment (28 h and 7 days). Furthermore, immunocytohistological studies, using JIM5 and JIM7 antibodies, revealed a decrease of labeling of both low- and high-methylesterified pectins in this maize line. The osmotic potential, quantified by means of incipient plasmolysis was lower in several types of cells of chilling-sensitive maize line which was correlated with the accumulation of sucrose. These studies present new finding on the effect of cold stress on the cell wall properties in conjunction with changes in the osmotic potential of maize leaf cells.

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Main conclusion The changes in the expression of key sugar metabolism enzymes (SPS and SUS), sucrose content and arrangement of chloroplast starch may play a significant role in the cold response in M. giganteus and maize plants.

Highlight: The level of pathogen alpha-amylase and plant beta-amylase activities could be components of plant-pathogen interaction associated with the resistance of triticale to Fusarium head blight.Triticale was used here as a model to recognize new components of molecular mechanism of resistance to Fusarium head blight (FHB) in cereals. Fusarium-damaged kernels (FDK) of two lines distinct in levels of resistance to FHB were applied into a proteome profiling using two-dimensional gel electrophoresis (2-DE) to create protein maps and mass spectrometry (MS) to identify the proteins differentially accumulated between the analyzed lines. This proteomic research was supported by a measurement of alpha- and beta-amylase activities, mycotoxin content, and fungal biomass in the analyzed kernels. The 2-DE analysis indicated a total of 23 spots with clear differences in a protein content between the more resistant and more susceptible triticale lines after infection with Fusarium culmorum. A majority of the proteins were involved in a cell carbohydrate metabolism, stressing the importance of this protein group in a plant response to Fusarium infection. The increased accumulation levels of different isoforms of plant beta-amylase were observed for a more susceptible triticale line after inoculation but these were not supported by a total level of beta-amylase activity, showing the highest value in the control conditions. The more resistant line was characterized by a higher abundance of alpha-amylase inhibitor CM2 subunit and simultaneously a lower activity of alpha-amylase after inoculation. We suggest that the level of pathogen alpha-amylase and plant beta-amylase activities could be components of plant-pathogen interaction associated with the resistance of triticale to FHB.

Resistance to Fusarium head blight in 32 winter triticale and 34 winter wheat accessions was evaluated. Triticale and wheat were sown in field experiments in two locations. At the time of flowering, heads were inoculated with three Fusarium culmorum isolates. Fusarium head blight index was scored and after the harvest percentage of Fusarium damaged kernels was assessed. Grain was analysed for type B trichothecenes (deoxynivalenol and derivatives, nivalenol) and zearalenone (ZEN) content. The average Fusarium head blight indexes were 28.0% for wheat and 19.2% for triticale accessions. The percentage of Fusarium damaged kernels was also higher for wheat and came to 55.6%, while for triticale this figure was 40.2%. The average content of deoxynivalenol (DON) for wheat amounted to 11.65 mg/kg and was lower than the result for triticale which was 14.12 mg/kg. The average contents of nivalenol were similar in both cereals: 4.13 mg/kg and 5.19 mg/kg for wheat and triticale respectively. Considerable amounts of DON derivatives in the cereals were also detected. The ZEN content in the grain was 0.60 mg/kg for wheat and 0.66 mg/kg for triticale. Relationships between Fusarium head blight index, Fusarium damaged kernels and mycotoxin contents were statistically significant for wheat and mostly insignificant for triticale. Triticale proved to have less infected heads and kernels than wheat. However, the content of type B trichothecenes was higher in triticale grain than in wheat grain.

Sucrose and starch concentration, sucrose phosphate synthase (SPS) activity in leaves, and long distance transport were studied in maize seedlings treated with moderate chilling (14 °C/12 °C -day/night).Two inbred lines were tested: chilling-tolerant KW1074 and chilling-sensitive CM109. Seedlings were grown in phytotrone on water nutrient tmtil the 4-th leaf appearance. The estimations were done on fully developed 2-nd leaf.Six days after the temperature was lowered, leaves of line KW 1074 plants contained 5-fold more sucrose and starch than the control ones. The same treatment of CM 109 seedlings resulted in accumulation of sucrose and starch by 2-fold and 8.5-fold, respectively.As the result of chilling-treatment, 14C assimilation rate (Pa), transport speed in the leaf blade (TS1) and along the plant (TSm) decreased by about 50 % in both lines. On the other hand, time necessary for radiolabel movement into the phloem loading region (AT) increased strongly, especially in chilling-sensitive line CM 109. It was also noted, that the radioactivity exported from leaves (RI) and imported by roots (Rm) decreased in line CM 109, and increased slightly in line KW 1074.The activity of SPS extracted from leaves of both lines decreased by about 3.3 when temperature was lowered form 30°C to 10°C. There was no effect of 6 day treatment of chilling on SPS activity.Changes in sucrose and starch concentration, SPS activity as well as differences in transport parameters observed in KW1074 and CM109 seedlings at moderate low temperatures are discussed in terms of mechanism of maize chillingsensitivity.List of abbreviations: Pa-14CO2 assimilation rate;AT -time of radioactivity appearance in the loading region; R 1 -radioactivity of leaves near the feeding area, Rm -radioactivity of mesocotyl; TSI -speed of translocation in the leaf blade; TS m -speed of translocation between leaf and mesocotyl, PCMBS p-chloromercuribenzen esulphonic acid, SPS -sucrose phosphate synthase