Fusarium in oats: infection time, DON and germination. Selamawit Tekle, Xinyao He,Helge Skinnes, Morten Lillemo, Åsmund Bjørnstad

Transcription

1 Fusarium in oats: infection time, DON and germination Selamawit Tekle, Xinyao He,Helge Skinnes, Morten Lillemo, Åsmund Bjørnstad

2 Introduction Oats Important cereal crop in the Northern hemisphere Unique in its nutritional composition Norway and FHB High levels of mycotoxins (DON, HT2/T2) in samples collected from farmers fields F. graminearum main DON producer and F. langsethiae main T2/HT2 producer Our experiments 2 Field and greenhouse trials since 2007 Spawn and spray inoculations Vollebekk Research Farm, Ås

3 Outline 1. The infection process of F. graminearum in oats focusing on optimal time of infection and the entrance pathways into the floral cavity and the caryopsis 2. The germination problem of Fusarium-damaged oats in relation to DON level and seed infection 3. Evaluation and identification of resistance to FHB in RILs and international collection of oat genotypes 3

4 1. The infection process of F. graminearum in oats 4

5 % ppm NORWEGIAN UNIVERSITY OF LIFE SCIENCES Time of infection Field experiments Saint paul Ås, Norway 100 Germination Infection DON 24 Greenhouse Un-inoculated control A-2 A+5 A+12 A+19 Yellow maturity 0 Time of inoculation

6 Infection pathways Apical infection during the first few days after inoculation Basal infections observed only after the disease has spread to the entire floret 6

7 Infection pathways 7 Hyphae of F. graminearum observed as early as 1 DAI Symptoms started to develop at 3 DAI Floret mouth principal entry pathway to the internal surfaces of the palea and lemma and to the caryopsis

8 Role of Anthers Profuse fungal growth on anthers than other floret parts 8 Genotypes with strong anther extrusion had lower rate of infection than the normal genotypes

9 Spread of infection in a panicle 9

10 2. Germination capacity of Fusariumdamaged oats in relation to DON level and seed infection 10

11 Objectives Investigate the relationship between seed infection, DON level and germination capacity Evaluate impact of prevailing weather conditions during and after flowering and inoculation techniques on germination and DON level Evaluate effect of fungicide treatment and dehulling on GC 11

12 Summary data for germination and DON level of field experiments ( ) 2007 spawn 2008 spawn 2009 spawn 2009 spray 2010 spawn DON GC DON GC DON GC DON GC DON GC # Genotypes Mean Maximum Minimum StDv* Correlation P

13 13 Summary data for germination and DON level of check genotypes 2007 spawn 2008 spawn 2009 spawn 2009 spray 2010 spawn Genotype DON GC DON GC DON GC DON GC DON GC Aveny Belinda Gere GN GN GN Hurdal Nes NK Odal Ringsaker Steinar Mean Correlation P

14 NORWEGIAN UNIVERSITY OF LIFE SCIENCES 14 Mean Temperature ( 0 C) Total precipitation (mm) # days > 2 mm precipitation July August Mean July August Sum July August Sum

15 Spray inoculation strong negative correlation than spawn inoculation Late infections by ascospores from the spawn inoculum accompanied by late season precipitation may depress the germination though seedling blight 15

16 Germination and DON DON did not inhibit germination per se but retarded seedling growth. Contamination of kernels with the toxin will result in abnormal and less vigorous seedlings with shorter coleoptiles and roots. 16

17 Mean seed viability (%), germination capacity (GC, %), and individual and combined effects of dehulling, seed dressing, and level of seedling blight of Fusarium-affected oat seed lots. Samples Seed viability Untreated Seed dressed Mean GC Dehulled Dehulled + Seed dressed Dehulling Effect of* Seed dressing Dehulling + Seed dressing Seedling blight** stored Presence of hulls protects viable propagules of Fusarium spp. 17 If used individually, dehulling and seed dressing are not enough to restore GC but together will allow germination of all kernels with viable germ.

18 3. Evaluation of resistance to FHB - 2 RIL populations - CORE collection 18

19 19 Linkage mapping and QTL identification of Fusarium head blight in RIL populations of oat (Avena sativa L.) Objectives to construct linkage maps based on recombinant inbred lines (RIL) between Hurdal x Z595-7 To identify genomic regions that confer resistance to DON accumulation Hurdal local adapted, early maturing and an moderately resistant Norwegian oat cultivar Z595-7 Back cross derivative of an A. sterilis accession PI from Eritrea into the US cultivar Ogle Z615-4 Back cross derivative of an A. sterilis accession PI from Eritrea into the US cultivar Tippecanoe

20 Materials and Methods The RILs were made by single seed descend method, and F8 generations of 184 lines from HZ595, and 91 lines from HZ615 were used for mapping Hill plots in 2008 and D-plots in 2009 and 2010 with two replications DON, Plant height, days to flowering and days to yellow maturity were scored SSR, AFLP and DArT, and SNP markers were applied 20

21 Line frequency Line frequency Line frequency NORWEGIAN UNIVERSITY OF LIFE SCIENCES 21 Results: HZ595 0,35 0,30 0,25 0,20 0,15 0,10 0,05 0,00 0,30 0,25 0,20 0,15 0,10 0,05 0,00 0,40 0,30 0,20 0,10 Z595- Hurdal DON 2008 < >12 Hurdal Z595-7 DON 2009 < >37 Both parents DON 2010 low DON in 2008 to very high DON in 2009, due to very wet climatic condition in 2009 The distribution of DON content in all the three years was continuous and close to normality Transgressive segregation was apparent, showing that both parents contributed resistance genes, also shown by the different ranks of the two parents 0,00 < >20 DON content (ppm)

22 22 Pearson correlation coefficients between DON level and agronomic traits and narrow sense heritability estimates of DON content in the HZ595 population DON content Days to heading (DH) *** Plant height (PH) * Days to maturity (DM) *** Heritability Unlike in 2010, in 2008 and 2009 there was no significant correlations between DON level and agronomic traits The heritability estimates were low, especially for DON 2008 and DON 2009 due to the low phenotypic variances under low and high disease pressures, respectively.

23 Composite interval mapping (CIM) of DON, FHB and other agronomic traits in the HZ595 population Chromosome QTL region Marker interval DON DON DON DH DM PH (cm) mean 2010 mean 5C opt AME D opt-6852 opt D_2 0-1 opt P44M A opt-5635 opt A opt-0657 opt A P32M opt A opt-4030 opt D 0-7 opt AME A opt P35M A opt-9631 P32M D AME13 P31M A opt opt Accumulated percentage of explained phenotypic variance

24 DON10 DON09 DON08 NORWEGIAN UNIVERSITY OF LIFE SCIENCES Chromosome 17A, HZ595 Chr_17A GMI_ES01_c25270_71 opt P32M66-80 GMI_ES01_c17183_318 opt opt-7733 opt GMI_ES17_c20752_1084 GMI_ES17_c2826_360 GMI_ES15_c5289_317 GMI_ES17_c15844_381 opt opt opt opt-7687 opt-1879 opt opt-6375 opt-8654 opt opt-9631 opt opt GMI_ES02_c11747_563 GMI_ES01_c8777_202 P32M opt-9004 GMI_ES17_c18122_180 P31M GMI_ES17_c1315_660 Example 6 DON08 DON09 DON10 FHB PH DH DM 24

25 Line frequency Line frequency NORWEGIAN UNIVERSITY OF LIFE SCIENCES 0,40 0,35 0,30 0,25 0,20 0,15 0,10 0,05 0,00 Frequency distributions of DON content and FHB severity in the Hurdal x Z615-4 population in 2011 Z615-4 DON 2011 Hurdal < >18 DON content (ppm) 0,50 FHB ,45 0,40 0,35 0,30 Hurdal 0,25 Z ,20 0, ,10 0,05 0, FHB severity

26 0 DON NORWEGIAN UNIVERSITY OF LIFE SCIENCES Chromosome 17A, HZ615 Chr_17A opt-6375 opt opt P32M opt-5886 opt opt-0511 DON FHB PH DH DM Example P34M P32M17-53 opt-9004

27 HZ595_10D2 opt opt opt P35M17-88 HZ615_10D opt-3298 opt-2136 opt opt-3335 AME Example 3 HZ595_13A P34M opt-8179 AME92 opt P77M opt opt opt opt opt opt opt opt opt opt-8715 HZ615_13A3 opt opt AME105 opt-8883 P37M opt opt Example 3 HZ595_17A opt opt opt P32M opt-9004 P31M HZ615_17A opt P32M opt opt opt opt-4915 P32M opt /19/2012 8/19/2012 C:\Users\hxinyao\Desktop\MapChart\Align 10D.mct C:\Users\hxinyao\Desktop\MapChart\Align 13A.mct 8/19/2012 1/1 C:\U

28 NORWEGIAN UNIVERSITY OF LIFE SCIENCES CORE spring oats collection currently being evaluated for FHB 28