Fitness traits of deoxynivalenol and nivalenol-producing Fusarium graminearum species complex strains from wheat

Abstract

Fusarium graminearum of the 15-acetyl(A)deoxynivalenol(D0N) chemotype is the main cause of Fusarium head blight (FHB) of wheat in south of Brazil. However, 3-ADON and nivalenol(NIV) chemotypes have been found in other members of the species complex causing FHB in wheat. To improve our understanding of the pathogen ecology, we assessed a range of fitness-related traits in a sample of 30 strains representatives of 15-ADON (F. graminearum), 3-ADON (F. cortaderiae and F. austroamericanum) and NIV (F. meridionale and F. cortaderiae). These included: perithecia formation on three cereal-based substrates, mycelial growth at two suboptimal temperatures, sporulation and germination, pathogenicity towards a susceptible and a moderately resistant cultivar and sensitivity to tebuconazole. The most important trait favoring F. graminearum was its 2x higher sexual fertility (> 40% PPI = perithecia production index) than the other species (< 30% PPI); PPI varied among substrates (maize > rice > wheat). In addition, sensitivity to tebuconazole appeared lower in F. graminearum which had the only strain with EC50 > 1 ppm. In the pathogenicity assays, the DON-producers were generally more aggressive (1.5 to 2x higher final severity) towards the two cultivars, with 3-ADON or 15-ADON leading to higher area under the severity curve than the NIV strains in the susceptible and moderately resistant cv., respectively. There was significant variation among strains of a same species with regards asexual fertility (mycelial growth, macroconidia production and germination), which suggest a strain-rather than a species-specific differences. These results contribute new knowledge to improve our understanding of the pathogen-related traits that may explain the dominance of certain members of the species complex in specific wheat agroecosystems.

Characterization of Fusarium asiaticum and F. graminearum isolates from gramineous weeds in the proximity of rice fields in Korea

“…Trichothecenes have been reported as important factors in the aggressiveness of FHB disease in wheat and other cereal crops (Goswami & Kistler, 2004;Proctor et al, 1995) Liu et al, 2017;Nicolli et al, 2018;Yang et al, 2018). The aggressiveness of the 3ADON and 15ADON chemotypes varies in wheat.…”

Gramineous weeds near paddy fields are alternative hosts for the Fusarium graminearum species complex that causes fusarium head blight in rice

“…Fusarium graminearum species complex isolates vary in their ability to cause disease in different hosts (Goswami and Kistler, ). In general, both 3ADON and 15ADON chemotypes of F. graminearum and F. asiaticum are more aggressive than NIV chemotypes of F. asiaticum , F. meridionale , and F. cortaderiae in wheat (Starkey et al , ; Spolti et al , ; Umpiérrez‐Failache et al , ; Liu et al , ; Nicolli et al , ; Yang et al , ; Amarasinghe et al , ). However, there have been few reports on the pathogenicity of FGSC isolates in rice (Goswami and Kistler, ; Lee et al , ; Gomes et al , ).…”

The FaFlbA mutant of Fusarium asiaticum is significantly increased in nivalenol production

“…Generally, the worldwide ubiquitously distributed organism F. graminearum produces mainly DON and its acetyl derivatives (Desjardins, 2006;van der Lee et al, 2015;Qiu et al, 2019;Yli-Mattila et al, 2011), while F. asiaticum strains, predominantly distributed in Asia, produce NIV and 4-AcNIV (Dong et al, 2020;Karugia et al, 2009;Lee et al, 2002Lee et al, , 2009Lee et al, , 2011. NIV-producing species also include F. meridionale, F. cortaderiae and F. austroamericanum (Nicolli et al, 2018). In this study, the ability to produce NIV was compared among 62 F. asiaticum NIV chemotype strains isolated from rice in Jiangsu Province, China.…”