Department of Agricultural, Food and Environmental Sciences, University of Perugia, Borgo XX Giugno 74, 06121 Perugia, Italy.
Department of Statistics, North Carolina State University, 27695 Raleigh, USA.
Int J Food Microbiol. 2019 Feb 2;290:214-225. doi: 10.1016/j.ijfoodmicro.2018.10.014. Epub 2018 Oct 17.
Fusarium head blight (FHB) results in yield loss and damaging contamination of cereal grains and can be caused by several Fusarium species. The objective of the present study was to determine, in a greenhouse experiment on winter wheat, how FHB was affected by timing of infection (0, 3, 6 or 9 days after anthesis, daa) by the aggressive species Fusarium graminearum compared to the relatively weak species Fusarium avenaceum, Fusarium poae and Fusarium acuminatum. Measures of FHB development were: symptoms in spikes (visually assessed), fungal biomass (quantified by real time quantitative PCR) and accumulation of fungal secondary metabolites (quantified by liquid chromatography-tandem mass spectrometry) in kernels. With regard to symptoms, F. graminearum was unaffected by inoculation timing, while the weaker pathogens caused greater disease severity at later timings. In contrast, the accumulation of F. graminearum biomass was strongly affected by inoculation timing (3 daa ≥ 6 daa ≥ 0 daa = 9 daa), while colonization by the weaker pathogens was less influenced. Similarly, F. graminearum secondary metabolite accumulation was affected by inoculation timing (3 daa ≥ 6 daa ≥ 0 daa = 9 daa), while that of the weaker species was less affected. However, secondary metabolites produced by these weaker species tended to be higher from intermediate-late inoculations (6 daa). Overall, infection timing appeared to play a role particularly in F. graminearum colonization and secondary metabolite accumulation. However, secondary metabolites of weaker Fusarium species may be relatively more abundant when environmental conditions promote spore dispersal later in anthesis, while secondary metabolites produced by F. graminearum are relatively favored by earlier conducive conditions.
镰刀菌穗腐病（FHB）会导致谷物减产和严重污染，可由几种镰刀菌引起。本研究的目的是在冬小麦温室试验中，确定与相对较弱的物种禾谷镰刀菌（ Fusarium avenaceum ）、禾谷镰刀菌（ Fusarium poae ）和尖孢镰刀菌（ Fusarium acuminatum ）相比，侵袭性物种禾谷镰刀菌（ Fusarium graminearum ）在感染时间（开花后 0、3、6 或 9 天，daa）上对 FHB 的影响。FHB 发展的测量指标有：穗部症状（目测评估）、真菌生物量（实时定量 PCR 定量）和籽粒中真菌次生代谢物的积累（液相色谱-串联质谱定量）。就症状而言，禾谷镰刀菌不受接种时间的影响，而较弱的病原体在较晚的时间会导致更大的疾病严重程度。相比之下，禾谷镰刀菌生物量的积累强烈受到接种时间的影响（3 daa ≥ 6 daa ≥ 0 daa = 9 daa），而较弱病原体的定植受影响较小。同样，禾谷镰刀菌次生代谢物的积累也受到接种时间的影响（3 daa ≥ 6 daa ≥ 0 daa = 9 daa），而较弱物种的次生代谢物受影响较小。然而，这些较弱物种产生的次生代谢物在中期至晚期接种时往往更高（6 daa）。总体而言，感染时间似乎在禾谷镰刀菌定植和次生代谢物积累方面起着特别重要的作用。然而，当环境条件有利于开花后孢子扩散时，较弱镰刀菌物种的次生代谢物可能相对更丰富，而禾谷镰刀菌产生的次生代谢物则相对更有利于早期的有利条件。
