| Fusarium is an important phytopathogenic fungus with a wide range of hosts such as corn,wheat,rice and other cereal crops.Most members of this genus can produce mycotoxins which causes food safety problems for humans and animals.The genus has numerous species which are morphologically indistinguishable,causing great difficulties in isolation,identification and diagnosis of associated diseases.Identifying the species of Fusarium causing maize stalk rot disease is the premise to design effective integrated control strategy for this disease.In this study,15 Fusarium spp.were isolated from more than 300 symptomatic maize samples,collected from the major maize growing regions of China.These species of Fusarium were classified,on the basis of morphological characteristic and phylogenetic relationships.They are F.asiaticum,F.boothii,F.brachygibbosum,F.cerealis,F.cortaderiae,F.graminearum,F.meridionale,F.fujikuroi,F.proliferatum,F.temperatum,F.verticillioides,F.equiseti,F.incarnatum,F.oxysporum and F.avenaceum,respectively.Among them,maize stalk rot disease caused by F.brachygibbosum and F.cerealis were first reported in the world.The 15 species of Fusarium belong to five species complexes.F.graminearum,F.meridionale,F.boothii,F.asiaticum,F.cortaderiae,F.cerealis and F.brachygibbosum belong to the F.sambucinum species complex(FSAMSC).Phylogenetic analysis showed that these species had obvious geographical distribution characteristics.The species of Fusarium isolated from Yunnan formed an independent branch,and these include F.meridionale,F.boothii and F.asiaticum.F.graminearum is the predominant species in the Huang-Huai-Hai plain.We found four species belong to F.fujikuroi species complex(FFSC),such as F.fujikuroi,F.proliferatum,F.temperatum and F.verticillioides.Phylogenetic analysis showed that F.verticillioides is far from the other three isolates and F.fujikuroi and F.proliferatum are relatively close.In addition,there are also obvious differences in geographical distribution among these species.F.verticillioides and F.fujikuroi are mainly distributed in the Huang-Huai-Hai area,and are rarely found in Yunnan,while F.temperatum is mainly distributed in Yunnan.F.temperatum is a new species that was first isolated and identified from maize stalk rot disease samples in Belgium by Scauflaire et al.in 2011.Currently,this fungus was resulted in maize stem rot disease in 19 provinces of China,and also produced various mycotoxins including fumonisin,frustracin and beauvericin.Therefore,we have developed a rapid detection method for F.temperatum according to Loop-mediated isothermal amplification technology.This method can accurately detect this fungus both in maize stalks and kernels and has potential application value for the rapid detection. |
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