Virulence structure of Blumeria graminis f. sp. tritici, the causal agent of wheat powdery mildew, in Ontario, Canada, in 2018 and 2019

Figures & data

Fig. 1 Location of origin of 42 isolates of Blumeria graminis f. sp. tritici collected in Ontario, Canada, in 2018 and 2019

Table 1. List of 24 differential wheat genotypes and their resistance genes used to characterize the virulence structure of Blumeria graminis f. sp. tritici populations in Ontario, Canada, in 2018 and 2019

Genotype^a	Resistance gene	Pedigree
C.I. 14114	Pm1a	Axminster/8*Chancellor (Sears and Briggle 1969)
MocZlatka	Pm1b	ATRI-1509-SLK(TR.MO)/(TR.DR)ATRI-3310-SLK//*Zlatka[1934] (Hsam et al. 1998)
M1N	Pm1c	Derived from Blaukorn Weihenstephan (Hsam et al. 1998)
C.I. 14118	Pm2	Ulka/8*Chancellor (McIntosh and Baker 1970)
C.I. 14120	Pm3a	Asosan/8*Chancellor (Briggle and Sears 1966)
Ralle	Pm3d	Svenno/Parlo//2149.60 (Heun and Friebe 1990)
C.I. 15888	Pm3f	Michigan Amber/8*Chancellor (Zeller et al. 1993)
Ronos	Pm4b	Graf/Kormoran//Kronjuwel (Yi et al. 2008)
C.I. 14125	Pm5a	Hope/8*Chancellor (Johnson et al. 1979)
I5	Pm5d	Unknown, collected in Shanxi, China, Accession: PI 83395, USDA-ARS
Wembley	Pm12	Hobbit/Sona 227//Sicco (Singh et al. 2001)
Pm16-13LW	Pm16	Norman/T. dicoccoides line (Reader and Miller 1991)
Amigo	Pm17	Teewon”S”/6/Gaucho/4/Tascosa/3/Wichita/Teewon/5/2*Teewon (Heun et al. 1990)
Pm21_Lukaszewski	Pm21	Derived from Haynaldia villosa (Lukaszewski and Cowger 2017)
NC96BGTA5-Ab	Pm25	Saluda/PI427662//Saluda/3/Saluda (Shi et al. 1998)
Pova	Pm29	Derived from Aegilops ovata (Zeller et al. 2002)
C20	Pm30	87–1/C20//2*8866 selection (Liu et al. 2002)
L501	Pm32	Rodina*6/Ae. speltoides (Hsam et al. 2003)
NC96BGTD7-Ab	Pm34	Saluda *3/TA2492 (Miranda et al. 2006)
NC96BGTD3-Ab	Pm35	Saluda *3/TA2377 (Miranda et al. 2007)
NC96BGTAG11-Ab	Pm37	Saluda *3/T. timopheevii accession (Perugini et al. 2008)
CH5025	Pm43	76216–96/TAI7045//2*Jing 411 (He et al. 2009)
NC06BGTAG12	MlAG12	Saluda *3/PI 538457 (Maxwell et al. 2009)
NC06BGTAG13	NCAG13	Saluda *3/PI 427442 (Murphy et al. 2007)

^aSeeds were obtained from the United States Department of Agriculture-Agricultural Research Service (USDA-ARS) in Raleigh, NC, USA.

Fig. 2 (Colour online) Powdery mildew symptoms developed on leaf segments of wheat genotypes containing Pm1a (1), Pm1c (3), Pm1d (4), Pm1e (5), Pm2 (6), or no effective Pm (c) genes, 12 d after inoculation with a Blumeria graminis f. sp. tritici isolate from Virulence Phenotype 33

Table 2. Virulence phenotypes (VP) identified from 42 Blumeria graminis f. sp. tritici isolates collected from greenhouses (G) and commercial fields and research plots (F&P) in Ontario, Canada, in 2018 and 2019

	Virulence formula	# virulence	2018		2019		Origin
VP #	(Avirulence Pm gene/Virulence Pm gene)	genes	#	%	#	%	G	F&P
VP1	1a,1b,1 c,2,3a,3d,3 f,4b,5a,12,16,21,25,29,30,32,34,35,37,43,MIAG12,NCAG13/5d,17	2	0	0.0	1	4.2	0	1
VP2	1a,1b,1 c,3a,3d,3 f,4b,12,16,17,21,25,29,30,32,34,35,37,43,MIAG12,NCAG13/2,5a,5d	3	0	0.0	1	4.2	0	1
VP3	1a,1b,1 c,3a,3d,3 f,4b,5a,12,16,17,21,25,29,30,34,35,37,43,MIAG12,NCAG13/2,5d,32	3	0	0.0	1	4.2	1	0
VP4	1a,1b,1 c,2,3d,3 f,4b,5d,12,16,17,21,25,29,30,32,34,37,43,MIAG12,NCAG13/3a,5a,35	3	1	5.6	0	0.0	0	1
VP5	1a,1b,1 c,3d,3 f,4b,12,16,17,21,25,29,30,32,34,35,37,43,MIAG12,NCAG13/2,3a,5a,5d	4	0	0.0	1	4.2	0	1
VP6	1a,1b,1 c,3a,3d,3 f,4b,5d,12,16,21,25,29,30,32,34,37,43,MIAG12,NCAG13/2,5a,17,35	4	0	0.0	1	4.2	0	1
VP7	1a,1b,1 c,2,3d,5d,12,16,17,21,25,29,30,32,34,35,37,43,MIAG12,NCAG13/3a,3 f,4b,5a	4	1	5.6	0	0.0	0	1
VP8	1a,1b,1 c,2,3a,3d,4b,12,16,21,25,29,30,32,34,35,37,43,MIAG12,NCAG13/3 f,5a,5d,17	4	0	0.0	1	4.2	0	1
VP9	1a,1b,1 c,3d,4b,5d,12,16,17,21,25,29,30,32,34,37,43,MIAG12,NCAG13/2,3a,3 f,5a,35	5	0	0.0	1	4.2	0	1
VP10	1a,1b,1 c,3d,4b,5a,12,16,17,21,25,29,30,34,35,37,43,MIAG12,NCAG13/2,3a,3 f,5d,32	5	1	5.6	0	0.0	1	0
VP11	1a,1b,1 c,3d,3 f,4b,12,16,21,25,29,30,32,34,35,37,43,MIAG12,NCAG13/2,3a,5a,5d,17	5	0	0.0	1	4.2	0	1
VP12	1a,1b,1 c,2,3d,5d,12,16,21,25,29,30,32,34,35,37,43,MIAG12,NCAG13/3a,3 f,4b,5a,17	5	1	5.6	0	0.0	0	1
VP13	1a,1b,1 c,2,3d,4b,5d,12,16,17,21,25,29,30,34,37,43,MIAG12,NCAG13/3a,3 f,5a,32,35	5	1	5.6	0	0.0	0	1
VP14	1a,1b,1 c,3d,4b,5d,12,16,17,21,25,29,32,34,37,43,MIAG12,NCAG13/2,3a,3 f,5a,30,35	6	0	0.0	1	4.2	0	1
VP15	1a,1b,1 c,3d,3 f,5a,5d,12,16,17,21,25,29,34,35,37,MIAG12,NCAG13/2,3a,4b,30,32,43	6	0	0.0	1	4.2	1	0
VP16	1a,1b,1 c,2,5a,12,16,17,21,25,29,30,32,34,37,43,MIAG12,NCAG13/3a,3d,3 f,4b,5d,35	6	0	0.0	1	4.2	0	1
VP17	1a,1b,1 c,3d,12,16,17,21,25,29,30,32,34,35,37,MIAG12,NCAG13/2,3a,3 f,4b,5a,5d,43	7	1	5.6	0	0.0	0	1
VP18	1a,1b,1 c,3d,5d,12,16,17,21,25,29,30,34,35,37,MIAG12,NCAG13/2,3a,3 f,4b,5a,32,43	7	1	5.6	0	0.0	0	1
VP19	1a,1b,1 c,3d,5a,12,16,17,21,25,29,30,34,35,37,MIAG12,NCAG13/2,3a,3 f,4b,5d,32,43	7	0	0.0	1	4.2	1	0
VP20	1a,1b,1 c,3d,4b,12,16,21,25,29,30,32,34,37,43,MIAG12,NCAG13/2,3a,3 f,5a,5d,17,35	7	0	0.0	2	8.3	0	2
VP21	1a,1b,1 c,3d,4b,5d,12,16,21,29,30,32,34,37,43,MIAG12,NCAG13/2,3a,3 f,5a,17,25,35	7	0	0.0	1	4.2	0	1
VP22	1a,1b,1 c,3d,4b,5a,12,16,17,21,29,30,34,37,43,MIAG12,NCAG13/2,3a,3 f,5d,25,32,35	7	1	5.6	0	0.0	1	0
VP23	1a,1b,1 c,3d,3 f,5d,12,16,17,21,25,29,32,34,37,MIAG12,NCAG13/2,3a,4b,5a,30,35,43	7	1	5.6	0	0.0	0	1
VP24	1a,1b,1 c,3a,5a,12,16,17,21,25,29,30,34,35,37,MIAG12,NCAG13/2,3d,3 f,4b,5d,32,43	7	0	0.0	1	4.2	1	0
VP25	1a,1b,1 c,3a,3d,5a,5d,12,16,21,25,29,34,35,37,MIAG12,NCAG13/2,3 f,4b,17,30,32,43	7	0	0.0	1	4.2	1	0
VP26	1a,1b,1 c,3a,3d,3 f,5a,12,16,21,29,34,35,37,43,MIAG12,NCAG13/2,4b,5d,17,25,30,32	7	1	5.6	0	0.0	1	0
VP27	1a,1b,1 c,2,3d,5d,12,16,17,21,25,29,32,34,35,37,43,MIAG12,NCAG13/3a,3 f,4b,5a,30,32,35	7	1	5.6	0	0.0	0	1
VP28	1a,1b,1 c,2,3d,4b,5d,12,16,21,25,29,32,37,43,MIAG12,NCAG13/3a,3 f,5a,17,30,34,35	7	0	0.0	1	4.2	0	1
VP29	1a,1b,1 c,4b,12,16,21,25,29,30,32,34,37,43,MIAG12,NCAG13/2,3a,3d,3 f,5a,5d,17,35	8	0	0.0	1	4.2	0	1
VP30	1a,1b,1 c,3d,12,16,17,21,25,29,32,34,37,43,MIAG12,NCAG13/2,3a,3 f,4b,5a,5d,30,35	8	0	0.0	1	4.2	0	1
VP31	1a,1b,1 c,3d,4b,12,16,21,25,29,30,34,37,43,MIAG12,NCAG13/2,3a,3 f,5a,5d,17,32,35	8	0	0.0	1	4.2	0	1
VP32	1a,1b,1 c,3d,4b,12,16,21,25,29,30,32,37,43,MIAG12,NCAG13/2,3a,3 f,5a,5d,17,34,35	8	0	0.0	1	4.2	0	1
VP33	1a,1b,1 c,3a,3d,3 f,5a,12,16,21,29,34,35,37,MIAG12,NCAG13/2,4b,5d,17,25,30,32,43	8	2	11.1	0	0.0	2	0
VP34	1a,1b,1 c,3d,4b,12,16,21,30,32,34,35,37,MIAG12,NCAG13/2,3a,3 f,5a,5d,17,25,29,43	9	1	5.6	0	0.0	0	1
VP35	1a,1b,1 c,3d,4b,5d,12,16,17,21,25,29,32,37,MIAG12/2,3a,3 f,5a,30,34,35,43,NCAG13	9	0	0.0	1	4.2	0	1
VP36	1a,1b,1 c,2,3d,5d,12,16,17,21,29,34,37,MIAG12,NCAG13/3a,3 f,4b,5a,25,30,32,35,43	9	1	5.6	0	0.0	0	1
VP37	1a,1b,1 c,3d,4b,12,16,21,29,34,35,37,MIAG12,NCAG13/2,3a,3 f,5a,5d,17,25,30,32,43	10	1	5.6	0	0.0	0	1
VP38	1a,1b,1 c,12,16,21,25,29,32,34,37,MIAG12,NCAG13/2,3a,3d,3 f,4b,5a,5d,17,30,35,43	11	0	0.0	1	4.2	1	0
VP39	1a,1b,1 c,5a,12,16,21,34,37,43,MIAG12,NCAG13/2,3a,3d,3 f,4b,5d,17,25,29,30,32,35	12	1	5.6	0	0.0	1	0
VP40	1a,1b,1 c,3d,5d,12,16,21,29,37,MIAG12,NCAG13/2,3a,3 f,4b,5a,17,25,30,32,34,35,43	12	1	5.6	0	0.0	0	1
Total			18	100	24	100	12	30

Table 3. Frequency of virulence of Blumeria graminis f. sp. tritici isolates collected from greenhouses and commercial fields in Ontario, Canada, in 2018 and 2019, on 24 single-gene powdery mildew differential lines

Resistance	% isolates from		% isolates from		% total
gene	2018	2019	Greenhouse	Field	isolates
Pm1a	0.0a^a	0.0a	0.0a	0.0a	0.0
Pm1b	0.0a	0.0a	0.0a	0.0a	0.0
Pm1c	0.0a	0.0a	0.0a	0.0a	0.0
Pm2	66.7a	83.3a	100.0a	66.7b	76.2
Pm3a	83.3a	70.8a	50.0b	86.7a	76.2
Pm3d	5.6a	16.7a	25.0a	6.7a	11.9
Pm3f	72.2a	70.8a	58.3a	76.7a	71.4
Pm4b	66.7a	29.2b	75.0a	33.3b	45.2
Pm5a	66.7a	70.8a	8.3b	93.3a	69.0
Pm5d	50.0a	62.5a	75.0a	50.0a	57.1
Pm12	0.0a	0.0a	0.0a	0.0a	0.0
Pm16	0.0a	0.0a	0.0a	0.0a	0.0
Pm17	44.4a	54.2a	50.0a	50.0a	50.0
Pm21	0.0a	0.0a	0.0a	0.0a	0.0
Pm25	50.0a	4.2b	41.7a	16.7a	23.8
Pm29	11.1a	0.0a	8.3a	3.3a	4.8
Pm30	50.0a	33.3a	66.7a	30.0b	40.5
Pm32	66.7a	25.0b	91.7a	23.3b	42.9
Pm34	5.6a	12.5a	0.0b	13.3a	9.5
Pm35	44.4a	58.3a	25.0b	63.3a	52.4
Pm37	0.0a	0.0a	0.0a	0.0a	0.0
Pm43	50.0a	25.0a	58.3a	26.7a	35.7
MlAG12	0.0a	0.0a	0.0a	0.0a	0.0
NCAG13	0.0a	4.2a	0.0a	3.3a	2.4
# isolates	18	24	12	30	42

^aValues in the same row followed by different letters between two years of collection or the greenhouse and field origins are significantly different at P < 0.05 according to the Student’s t-test.

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