Ascosporic and conidial inoculum of<i>Gibberella zeae</i>play different roles in Fusarium head blight and crown rot of wheat in Australia and the USA

Mitter, V.; Francl, L. J.; Ali, Shaukat; Simpfendorfer, S.; Chakraborty, Sukumar

doi:10.1071/ap06046

Cited by 27 publications

(22 citation statements)

References 34 publications

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“…There is an ecological adaptation among the three pathogens that further influence their fitness. Macroconidia, not ascospores, are the main inoculum source for FHB in Australia, and Australian Fg isolates produce fewer perithecia in culture or in the field compared with isolates from the USA (Mitter et al, 2006a). With winter snow covering wheat fields postharvest in the USA, the production of perithecia on crop residues is critical to pathogen survival.…”

Section: Discussionmentioning

confidence: 99%

Fitness of three Fusarium pathogens of wheat

Tunalı

Obanor

ERGİNBAŞ>

et al. 2012

FEMS Microbiol Ecol

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Crown rot and head blight of wheat are caused by the same Fusarium species. To better understand their biology, this study has compared 30 isolates of the three dominant species using 13 pathogenic and saprophytic fitness measures including aggressiveness for the two diseases, saprophytic growth and fecundity and deoxynivalenol (DON) production from saprophytic colonization of grain and straw. Pathogenic fitness was generally linked to DON production in infected tissue. The superior crown rot fitness of Fusarium pseudograminearum was linked to high DON production in the stem base tissue, while Fusarium culmorum and Fusarium graminearum had superior head blight fitness with high DON production in grains. Within each species, some isolates had similar aggressiveness for both diseases but differed in DON production in infected tissue to indicate that more than one mechanism controlled aggressiveness. All three species produced more DON when infecting living host tissue compared with saprophytic colonization of grain or straw, but there were significant links between these saprophytic fitness components and aggressiveness. As necrotrophic pathogens spend a part of their life cycle on dead organic matter, saprophytic fitness is an important component of their overall fitness. Any management strategy must target weaknesses in both pathogenic fitness and saprophytic fitness.

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Section: Discussionmentioning

confidence: 99%

Fitness of three Fusarium pathogens of wheat

Tunalı

Obanor

ERGİNBAŞ>

et al. 2012

FEMS Microbiol Ecol

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“…Under humid conditions, Fusarium produces conidia on infected stubbles and this can be used to directly measure fecundity. However, the role of conidia in CR infection is relatively minor (Mitter et al , 2006a) and since hyphae growing from infected crop residue are the primary means of infection of crown and stem base tissue (Burgess et al , 2001), pathogen biomass in stubble is an adequate measure of CR inoculum.…”

Section: Discussionmentioning

confidence: 99%

Production and fitness of Fusarium pseudograminearum inoculum at elevated carbon dioxide in FACE

Melloy

Hollaway²,

Luck

et al. 2010

Global Change Biology

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Rising atmospheric carbon dioxide (CO 2 ) concentration is increasingly affecting food production but how plant diseases will influence production and quality of food under rising CO 2 is not well understood. With increased plant biomass at high CO 2 the stubble-borne fungal pathogen Fusarium pseudograminearum causing crown rot (CR) of wheat may become more severe. We have studied inoculum production by Fusarium using fungal biomass per unit wheat stubble, stem browning from CR and the saprophytic fitness of Fusarium strains isolated from two wheat varieties grown in 2007 and 2008 at ambient and elevated CO 2 in free-air CO 2 enrichment (FACE) with or without irrigation and once in a controlled environment. Fungal biomass, determined using primers for fungal ribosomal 18s and the TRI5 gene, increased significantly at elevated CO 2 in two of the three studies. Stem browning increased significantly at elevated CO 2 in the 2007 FACE study. At elevated CO 2 increased stem browning was not influenced by irrigation in a susceptible variety but in a resistant variety stem browning increased by 68% without irrigation. Wheat variety was significant in regression models explaining stem browning and Fusarium biomass but pathogen biomass at the two CO 2 levels was not significantly linked to stem browning. Fusarium isolates from ambient and elevated CO 2 did not differ significantly in their saprophytic fitness measured by the rate of colonization of wheat straw. We show that under elevated CO 2 Fusarium inoculum in stubbles will be amplified from increased crop and pathogen biomass while unimpeded saprophytic fitness will retain its effectiveness. If resistant varieties cannot completely stop infection, Fusarium will rapidly colonize stubble to further increase inoculum once the crop is harvested. Research should move beyond documenting the influence of elevated CO 2 to developing disease management strategies from improved knowledge of pathogen biology and host resistance under rising CO 2 .

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“…This difference in the type of spores trapped was consistent between the two locations (P=0.436 and P=0.435 for the effect of location on numbers of ascospores and conidia, respectively). Prevalence of ascospores is not surprising because maize residues are a favourable substrate for ascospore production (Pereyra and Dill-Macky 2008) and ascospores have been found to be prevalent over conidia in other studies (Fernando et al 2000;Inch et al 2005;Markell and Francl 2003;Mitter et al 2006;Panisson et al 2002). However, F. graminearum survives on a wide range of plant material (Parry et al 1995) and there is limited information on whether the substrate affects the ascospore/conidium production ratio.…”

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confidence: 90%

Deposition patterns of Fusarium graminearum ascospores and conidia within a wheat canopy

2015

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Fusarium graminearum is the most important species in the fungal complex causing Fusarium head blight of small grain cereals. The fungus produces two types of spores on crop residues (ascospores and conidia), which are dispersed to ears by air currents and rain splashes, respectively. The distribution patterns of ascospores and conidia within a wheat canopy between booting and grain maturity were assessed by using leaflike spore traps placed at 10, 30, and 60 cm height, and ear-like spore traps at 90 cm height. Maize residues were the inoculum source for both ascospores and conidia within the wheat plot. Of the total spores counted, 93 % were ascospores and 7 % were conidia. Approximately 41, 22, 19, and 18 % of the ascospores, and 77, 10, 8, and 5 % of the conidia were sampled at 10, 30, 60, and 90 cm height, respectively. Ascospore numbers did not significantly differ between those sampled on the upper or the lower sides of the leaf-like traps or among the four orientations (north, south, east, or west) of the ear-like traps. According to the index of dispersion (D), the spatial distribution of trapped ascospores was largely random (i.e., D≤1) rather than aggregated (i.e., D>1). The collective results (averaged across all traps and sampling periods) showed that the random distribution of the ascospores within the wheat canopy and at the ear level was associated with a clear vertical distribution pattern indicating an upward movement of ascospores from the maize residues on the ground.

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Ascosporic and conidial inoculum ofGibberella zeaeplay different roles in Fusarium head blight and crown rot of wheat in Australia and the USA

Cited by 27 publications

References 34 publications

Fitness of three Fusarium pathogens of wheat

Fitness of three Fusarium pathogens of wheat

Production and fitness of Fusarium pseudograminearum inoculum at elevated carbon dioxide in FACE

Deposition patterns of Fusarium graminearum ascospores and conidia within a wheat canopy

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