Fusarium

Fusarium graminearum (Schwabe) and Fusarium culmorum (W. G. Smith Sacc.) are the main pathogens associated with head blight (“scab”) and root/foot rot diseases of wheat and barley. Both fungal pathogens belong to Ascomycete group by having a necrothrophic life cycle.  In particular, “Root and Foot Rot” disease have been reported as one of the most important yield limiting factors in Turkish barley growing fields.

Infection:

Fusarium culmorum penetrates directly through plant tissues while F. graminearum diffuse from stomata of glumes, lemmas, paleas or the rachilla. Nutrient and water uptake is prevented in plants with F. culmorum infection in which xylem vessels are blocked. Infected plants can be recognized by short heights and browning in their foot rots. Head blight symptoms can be determined by discolored, withered and light test-weighted kernels containing high amounts of mycotoxins including deoxynivalenol (DON), nivalenol (NIV) and their several acetylated derivatives. Studies on the occurrence of F. culmorum on wheat and barley as well as the other families such as Betulaceae and Cucurbitaceae in Turkey indicate that the pathogen is widespread in the northwestern and Central Anatolian plateau particularly in the spring. Turkey’s climate is very diverse accross the country. The soil characteristics and seasonal variations in cereal growing locations are therefore important factors affecting fungal occurrence. In Turkey, F. culmorum has been found to be a dominant species by its distribution frequency and occurrence in the dryland root rot complex (DLRRC) with the other species, Bipolaris sorokiniana and F. pseudograminearum.

 

Some of genome characteristics of F. graminearum:

 

Genome                                  : 36,1 –Mb

Chromosomes                        : Four submetacentric chromosomes with 7-11 Mb in size.

Predicted gene number          : 12.000

RNA annotations                   : 319 tRNA, 62 rRNA, 121 ncRNA, and 2 tmRNA

Functional categories for genes        : Transcription factors, Hydrolitic enzymes,    Transmembrane transporters

Mycotoxin synthesis                         : DON synthesis are related to 11 genes (Tri genes), Tri-gene cluster is located on chromosome 2

Transposons                                       : small families (gypsy type LTR retrotransposons)

Repetitive sequences                                     : low numbers

No. of SNPs                                       : 10,495 (Between the strains PH-1 and GZ3639)

 

References

Nelson PE et al. (1983). Fusarium Species. An illustrated manual for identification. The Penn State Univ Press, Pennsylvania-USA, pp. 193.

 Cuomo A et al. (2007) Science 317: 1400-1402.

Tunalı B et al (2013) J Basic Microbiol. 53(8):686-94

King R et al. (2015) BMC Genomics 16:544

F. culmorum genome sequence article

 

F16 on PDA.jpg

Fusarium culmorum pathogenic isolate F16 (Turkey origin) on PDA medium

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