Variable interactions between non-cereal grasses and Fusarium graminearum

Figures & data

Fig. 1 Survival of Fusarium graminearum in grass stems over two winters. Bars show per cent pathogen recovery from stems after one and two years of overwintering in artificially infested debris deposited outside in autumn 2016. Whiskers represent standard deviation of three replicates, each containing 10 stem segments. Lolium perenne was significantly less likely to be colonized than other hosts (P ≤ 0.001), and by year two all the grasses had decreased to less than 40% infestation rates (P < 0.001).

Fig. 2 Fusarium graminearum spore production on six different grasses. Bars are confidence intervals (95%) around least square means from a linear mixed model of (a) ascospore and (b) conidia production on grass stems averaged across 10 isolates of F. graminearum. The number of spores produced was significantly affected by host in both cases (F_5,8 = 14.30, P < 0.001 and F_5,8 = 43.45, P < 0.001, respectively).

Fig. 3 Incidence of root rot caused by five isolates of Fusarium on the seedlings of six grass species. Host species had a significant effect on disease incidence (F_5,419 = 91.04, P ≤ 0.001), and there was a significant interaction between host and isolate (F_20,419 = 3.01, P ≤ 0.001). Sample sizes are included below each bar.

Table 1. Fusarium isolates used in this study.

Isolate	Host	Chemotype^b	Overwintering	Spore production	Root rot
Fusarium graminearum
Gz5668NY15^a	Bromus inermis	15-ADON	X	X
Gz5673NY15	Hordeum jubatum	15-ADON	X	X
Gz5676NY15	Elymus canadensis	15-ADON	X	X
Gz6033NY16	Triticum aestivum	15-ADON	X	X
Gz6039NY16	T. aestivum	3-ADON	X	X
Gz6046NY16	T. aestivum	15-ADON	X	X
Gz5953NY16	Grass residue	15-ADON	X	X
Gz5911NY16	Grass residue	15-ADON	X	X
Gz5933NY16	Grass residue	3-ADON	X	X
Gz448NY13	Zea mays	15-ADON	X	X	X
Gz830NY11	Z. mays	NX-2			X
Gz014NY98	T. aestivum	15-ADON			X
Gz112VA10	–	NIV			X
Fusarium cerealis
Fc1134NY13	Hordeum vulgare	(NIV)			X

^a Isolate names are formatted as ‘Species-Collection Number-State-Year’

^b Determined by PCR based methods (Ward et al. 2008; Liang et al. 2014) prior to selection for use in root rot assay and after use in overwintering and spore production assays.

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