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Relationships between resistance to Fusarium head blight and crown rot in hexaploid wheat

Chunji Liu1*, Vivek Mitter1, Tom Magner1, Tomohiro Ban2, Sukumar Chakraborty1

1 CSIRO Plant Industry, Queensland Bioscience Precinct, 306 Carmody Road, St Lucia, Brisbane 4067, Australia; 2)

2 Japan International Research Center for Agricultural Sciences, Biological Resources Division, 1-1 Ohwashi, Tsukuba, Ibaraki
Prefec. 305-8686, JAPAN.
1
Corresponding author: chunji.liu@csiro.au

Abstract

Fusarium head blight (FHB) and crown rot (CR) were assessed against a common set of hexaploid wheat genotypes using two Fusarium isolates, one F. graminearum and the other F. pseudograminearum. There was a strong correlation between CR severity caused by the two isolates. Similarly, the correlation between FHB severity caused by the two isolates was also strong. However, there was no obvious relationship between CR and FHB severity caused by either isolate. Results suggest that once validated using more isolates, it may be possible to initially screen for CR resistance using a single isolate and many FHB resistant germplasm may not offer any resistance to CR. Hence, separate screening may need to be carried out for the two diseases.

Media Summary

Although caused by the same Fusarium pathogens, resistance to Fusarium head blight and crown rot may not be linked.

Keywords

Fusarium head blight – crown rot – wheat –host resistance

Introduction

CR is a major constraint to winter wheat production in Australia. This disease can inflict yield loss of up to 89% (Klein et al. 1991) and it costs the Australian grains industry $56 million per annum. The disease has recently become more prevalent, most likely as a result of the growing trend towards conservation farming practices involving stubble retention, as CR pathogens are carried over in residues (Wallwork et al. 2004).

Fusarium pseudograminearum is the main CR pathogen (Burgess et al. 1975), but F. culmorum causes CR in some of the higher rainfall areas of Victoria and South Australia (Wallwork et al. 2004) and several other Fusarium species can be involved (Chambers 1972; Burgess et al. 1975). An analysis of 650 Fusarium samples from Queensland and northern NSW has found that all Fusarium species causing CR can also cause FHB (Akinsanmi et al. 2004). This raises the question whether there is a correlation between CR and FHB resistance. If such a correlation exists, our effort to identify the best source of CR resistance can be simplified by exploiting available data on FHB resistance for a large set of genotypes. In China alone, 34,571 genotypes have been tested for FHB (Lu et al. 2001), and the total number of genotypes tested in the United States under the Wheat Scab Initiative could be even larger (R. Dill-Macky, pers. comm.). Large-scale FHB screenings have also been carried out by CIMMYT and other organizations (Gilchrist et al. 1997).

Materials and methods

Thirty-one wheat genotypes were used in this study (Table 1). FHB bioassay was carried out on 24 genotypes in a controlled environment facility at the CSIRO Plant Industry Brisbane Laboratories, with 25/15oC day/night temperature and 65/95% relative humidity, and a 13 -hour photoperiod. Highly aggressive isolates of F. pseudograminearum (isolate CS3096) and F. graminearum (isolate CS3255) were used. Each replicate consisted of two plants in two separate pots and two replicates were used for each isolate. Eight to ten spikes from each of the two replications were inoculated using a modified “cotton wool” method developed at CIMMYT. At anthesis a 3mm filter paper saturated with inoculum (about 10μl suspension of 105 conidia/mL) was placed into the fourth spikelet from the tip of a spike. The inoculated spikes were immediately covered with moistened polythene bags for 48 hours and then with a paper bag until disease assessment at 21 days after inoculation. The average number of infected spikelets was used as a measure of FHB severity.

Table 1. Genotypes used and their reaction to CR and FHB

 

FHB severity (no. of infected spikelets)

CR severity (length of stem discolouration)

Wheat germplasm

Isolate CS3255

Isolate CS3096

Isolate CS3255

Isolate CS3096

2-49

2.8

4.2

0.5

0.6

Abura komugi

4.1

7.9

1.9

2.1

Aso zairai (Yuubu kaf-)

1.3

6.7

1.1

2.1

Aso zairai 11

1.0

3.5

0.4

1.1

Baxter

not tested

not tested

3.1

1.7

Chile

8.0

9.6

1.6

1.9

Chinese Spring

not tested

not tested

9.2

14.2

CSCR05

2.5

2.0

0.0

0.3

Drysdale

Not tested

Not tested

6.3

6.9

Freedom

6.3

5.2

2.1

4.1

Frontana

8.1

8.0

6.0

6.1

Itou komugi

2.4

12.0

2.7

5.7

Janz

not tested

not tested

4.0

4.3

Kagoshima

1.2

2.5

2.8

3.5

Kennedy

not tested

not tested

4.5

6.0

Kikuchi

2.0

2.4

2.2

3.7

Lang

not tested

not tested

6.4

9.2

Ning-7840

2.3

3.6

7.6

7.2

Nobeokabouzu komugi

4.0

5.7

12.1

7.4

Nyuubai

2.2

4.7

7.1

8.1

Qiamai (Xiamai)

1.6

6.2

1.7

3.3

QT10776

not tested

not tested

6.1

3.9

Shiro nankin

2.1

3.1

1.4

2.7

Shou komugi 11

1.9

3.9

3.2

4.6

Soba komugi 1B

3.3

7.5

1.6

3.0

Soba komugi 1C

6.8

12.0

1.3

2.3

Sotome

2.8

3.4

4.2

5.6

Sotome A

2.9

4.6

3.9

4.9

Sumai 3

1.6

3.1

5.1

4.0

SVP-72017

2.4

1.8

2.8

2.6

Zairai yuubou

5.6

4.3

9.1

4.2

The same two isolates were used in a glasshouse bioassay to determine CR resistance of the 31 genotypes. The glasshouse is maintained at 24/15oC day/night temperature with natural illumination. Three replications with five seedlings each were tested for each genotype-isolate combination. Ten-day-old seedlings were inoculated by placing a 10μl droplet of inoculum (106 conidia/mL) on the stem, 0.5 to 1cm from the soil surface. The inoculated seedlings were kept in a humidity chamber for 48 hours then transferred back to the glasshouse. CR severity was assessed as the length of discoloured stem at 35 days after inoculation.

Results

CR severity caused by the F. graminearium isolate ranged from 0.0 to 12.1 with an average of 3.9, and that caused by the F. pseudograminearium isolate ranged from 0.3 to 14.2, with an average of 4.4. There is a significant correlation (r = 0.78) between CR severity caused by the two pathogens (Fig. 1A).

(A)

(B)

Figure 1. Relationship between CR severity (A) on 31 wheat genotypes and FHB severity (B) on 24 wheat genotypes caused by two isolates of F. graminearum and F. pseudograminearum

Twenty-four of the 31 genotypes (Table 1) were tested for FHB resistance using the same two Fusarium isolates. FHB severity caused by the F. graminearum isolate ranged from 1.0 to 8.1 (average 3.3), and 1.8 to 12.0 (average 5.3) for the F. pseudograminearum isolate. The correlation (r = 0.55) between FHB severity of the 24 wheat genotypes caused by the two pathogens was significant (Fig. 1B). However, an analysis of the 24 genotypes assessed for both CR and FHB found a weak correlation between CR and FHB resistance for both F. graminearum (r = 0.17, Fig. 2A) and F. pseudograminearum (r = 0.04, Fig. 2B) isolates.

(A)

(B)

Figure 2. Relationship between FHB and CR resistance in 24 wheat genotypes assessed using F. graminearum (A) and F. pseudograminearum (B) isolates

Discussion

FHB is a serious wheat disease and extensive screenings for sources of resistance have been carried out (Gilchrist et al. 1997; Lu et al. 2001; R. Dill-Macky, pers. comm). The resistance of the spring wheat cultivar Sumai3 is widely used in the world and its resistance has been the best characterized (Rudd et al. 2001). Genotypes with comparable or even better resistance than Sumai 3 have been reported and Nobeokabouzu komugi (NK) (Ban and Suenaga 2000) is one such line. Under our experimental conditions and pathogen isolates, Sumai3 has consistently shown better FHB resistance than NK in this study. Further studies are necessary on the effectiveness of FHB resistance in NK.

Unlike FHB that is a serious disease in many wheat production regions in the world, CR epidemics are limited to Australia, South Africa, Argentina and parts of the USA (Burgess et al., 1981)), though the disease may have remained undetected in other parts of the world (L. Gilchrist, per comm.). Current glasshouse and field screening methods for CR are time consuming and highly variable techniques (Wildermuth and McNamara 1994) and consequently, no reports on large-scale germplasm screening are available. Limited screening in Australia has identified several genotypes with partial CR resistance; of these 2-49 is the most resistant (Simpfendorfer 2003). Of the 31 genotypes tested in this study, several genotypes showed CR resistance comparable to that of 2-49. This is encouraging considering the small number of genotypes tested here and screening a more extensive range of genotypes may lead to CR resistance higher than that of 2-49.

The overall correlation between CR and FHB resistance in the 24 genotypes is weak for both Fusarium species, though several genotypes showed good levels of resistance to both diseases (Table 1). However, the majority of the genotypes used in this study had shown high levels of FHB resistance in previous studies (Ban and Suenaga 2000, Rudd et al. 2001, T. Ban unpublished). Other genotypes with low FHB resistance must be screened for CR resistance before any definite conclusions can be drawn. If through further studies, resistance to CR were only detected in a small number of FHB resistant genotypes and none in FHB susceptible genotypes, this in itself would be useful in narrowing down our search for CR resistance from the data on FHB resistance that have accumulated worldwide.

Acknowledgements

We are grateful to Phil Banks (QDPI, Australia), Harold Bockelman (USDA-ARS, USA) and Hermann Buerstmayr (Institute for Agrobiotechnology, Austria) for providing some of the genotypes, and Miki Miyagi for technical help. This project is partially funded by GRDC.

References

Akinsanmi OA, Mitter V, Simpfendorfer S, Backhouse D, Chakraborty S (2004) Identity and pathogenicity of Fusarium spp. Isolated from wheat fields in Queensland and northern New South Wales. Australian Journal of Agricultural Research 55:97-107

Ban T and Suenaga K (2000) Genetic analysis of resistance to Fusarium head blight caused by Fusarium graminearum in Chinese wheat cultivar Sumai 3 and the Japanese cultivar Saikai 165. Euphytica 113:87-99

Burgess L, Dodman R, Mayers P, Pont W (1981) Fusarium diseases of wheat, maize and grain sorghum in eastern Australia. In 'Fusarium: Diseases, Biology and Taxonomy'. (Eds P Nelson, T Toussoun and R Cook) pp. 64-76. (Pennsylvania State University Press, University Park)

Burgess LW, Wearing AH, Toussoun TA (1975) Survey of Fusaria associated with crown rot of wheat in eastern Australia. Australian Journal of Agricultural Research 26:791-799

Chambers SC (1972) Fusarium species associated with wheat in Victoria. Australian Journal of Experimental Agriculture and Animal Husbandry 12:433-436

Gilchrist L, Rajaram S, Mujeeb-Kazi A, van Ginkel M, Vivar H, Pfeiffer W (1997) Fusarium Scab screening Program at CIMMYT. In: Dubin HJ, Gilchrist L, Reeves J, and McNab A (eds): Fusarium Hea Scab: Global status and future prospects. Mexico, D.F.: CIMMYT. pp7-12

Klein TA, Burgess LW, Ellison FW (1991) The incidence and spatial patterns of wheat plants infected by Fusarium graminearum Group 1 and the effect of crown rot on yield. Australian Journal of Agricultural Research 42:399-407

Lu WZ, Cheng SH, Wang YZ (2001) Wheat Scab Research in China. Scientific Publication Ltd, Beijing, pp229. ISBN 7-03-009199-X.

Rudd JC, Horsley RD, McKendry AL, Elias EM (2001) Host plant resistance genes for Fusarium head blight: sources, mechanisms, and utility in conventional breeding systems. Crop Sci., 41:620-627

Simpfendorfer S (2003): GRDC Annual Report on "Strategic Initiative on crown rot, common root rot and Fusarium head blight", July 2002 - June 2003, Adelaide pp34.

Wallwork H, Butt M, Cheong JPE, Williams KJ (2004) Resistance to crown rot in wheat identified through an improved method for screening adult plants. Australasian Plant Pathology 33:1-7

Wildermuth GB, McNamara RB (1994) Testing wheat seedlings for resistance to crown rot caused by Fusarium graminearum group 1. Plant Disease 78:949-95

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