Temporal dynamics, population characterization and mycotoxins accumulation of Fusarium graminearum in Eastern China

Abstract

Trichothecene genotype composition, mycotoxin production, genetic diversity, and population structure were analyzed, using 185 Fusarium strains collected from wheat (Triticum aestivum L.) throughout the Jiangsu province during 1976, 1983, 1998, 2006, and 2014. The results showed that 3-acetyldeoxynivalenol (3ADON) was consistently the predominant type in this region over 40 years, and the nivalenol (NIV) type has emerged since 1998. Long-term rotation of wheat and rice (Oryza sativa L.), rather than fungicide application, crop fitness, or weather conditions, might be the main cause of this phenomenon. The genetic diversity results from two toxin synthetic genes, Pks4 and Tri10, and variable number of tandem repeat (VNTR) markers revealed the largest variance within the population in 1998, which was also the year with the highest production of mycotoxins. Population differentiation analysis indicated that major temporal population comparisons from the same area were not significantly differentiated. Our results showed that dominant species could maintain genetic stability for a long time, and Pks4 would be of utility in genetic and population studies.Fusarium head blight (FHB) is one of the most destructive and widespread diseases of wheat (Triticum aestivum L.), barley (Hordeum vulgare L.), and other cereals, globally. This disease reduces crop yields, causing extensive economic losses. More importantly, harvested grain quality is often compromised, due to mycotoxins produced by pathogens. Consumption of contaminated grains and products might have pernicious effects on human and animal health 1 . Fusarium graminearum species complex (FGSC) consists of at least 16 phylogenetically distinct species, and is the main causal agent of FHB [2][3][4][5][6][7] . Fusarium asiaticum is the predominant species in Asia 8-12 , while F. graminearum sensu stricto (s. str.) is present in most FHB-occurring areas around the world, especially in America and Europe 3,4,6 . Members of FGSC produce toxic secondary metabolites, among which trichothecene and zearalenone (ZEN) are the most closely monitored due to their high detection rates and strong toxicity. Trichothecene toxins, including deoxynivalenol (DON) and nivalenol (NIV), inhibit eukaryotic protein biosynthesis and cause some human and animal mycotoxicoses 13,14 . FGSC strains have been shown to possess one of three trichothecene genotypes: 3-acetyldeoxynivalenol (3ADON), or NIV 15 . Zearalenone (ZEN) and its metabolites have estrogen-like functions and strong teratogenic effects 16 . Moreover, ZEN has been shown to be genotoxic to cells and toxic to some animal tissues 17 . As a result, the mycotoxin-producing ability of individual isolates is always a concern.With the development of molecular biology, sequences and functions of members in the trichothecene biosynthetic gene cluster have been gradually elucidated. The first gene discovered in the trichothecene pathway was Tri5 18 , which catalyzes the first reaction in this pathway. Thereafter, the other 11 core genes...

Building on a foundation: advances in epidemiology, resistance breeding, and forecasting research for reducing the impact of fusarium head blight in wheat and barley

“…In Japan, F. graminearum is most prevalent in wheat fields in the northern parts of the country, which feature low temperatures, while F. asiaticum is the most abundant species in the southern region, which features higher temperatures (Suga et al 2008). Similar results with respect to geography have been obtained in China, where approximately 76% of isolates obtained from wheat in the northeast parts of the country were of the F. graminearum species, while 97% of isolates collected from the southern region were of the F. asiaticum species (Zhang et al 2010;Qiu et al 2016). Surveys undertaken in Argentina, Brazil, and Uruguay have also shown F. graminearum to be the major causative pathogen (Ramirez et al 2007;Reynoso et al 2011;Castañares et al 2014;Yerkovich et al 2020).…”

“…Additionally, the 3ADON isolates were more aggressive and showed higher levels of fungicide resistance. In China, VNTR marker analysis of 185 Fusarium isolates collected within a 28-year period resulted in a strong correlation between highgenetic diversity and mycotoxin production (Qiu et al 2016). These results suggest natural selection as a dominant force in the introduction of more toxigenic pathogens into a region.…”

Population Genetic Structure and Chemotype Diversity of Fusarium graminearum Populations from Wheat in Canada and North Eastern United States

“…The F. graminearum VNTR markers have been widely used in F. graminearum population genetic analysis [ 7 , 9 , 24 , 36 , 37 , 38 , 39 , 40 , 41 , 42 , 43 ]. In the current study, a high level of polymorphism was detected as indicated by the relatively high Shannon Index values across the geographic regions.…”

Fusarium Toxins in Chinese Wheat since the 1980s

“…The population structure and genetic variation in FHB pathogens have been studied in detail in Jiangsu Province, which has a long history of rice growing and a large rice-growing area that covers 30 million acres. The F. asiaticum strain that produced 3ADON has always dominated [60,61], and no similar evidence of temporal trends in the North American wheat population or Chinese barley population has been found [62,63,64,65,66]. Extensive wheat-rice rotation is critical for F. asiaticum overwintering, and perithecium production typically favors rice straw under warmer conditions.…”