GRDC Grains Research Update

Transcription

1 GRDC Grains Research Update Suppression of wheat & canola fungal diseases by endophytic biocontrol agents Margaret Roper, CSIRO with Cathryn O Sullivan, Cindy Myers and Louise Thatcher

2 The Research Team

3 Fungal diseases Cost to Australian grain & oilseed industries Wheat Root and Crown fungal diseases in total $196M annually Fusarium crown rot $80M Gaeumannomyces graminis (Take-all) $13M Rhizoctonia barepatch $60M Pythium damping off $10M (Murray and Brennan 2009) Canola Sclerotinia stem rot $10M Rhizoctonia root rot $2.6M (Murray and Brennan 2012)

4 Management Strategies to Control Crop Diseases Fungicides Seed dressings - little protection beyond seedling stage Foliar - concerns over timing and residues in grain Biotechnological approaches are difficult Range of disease-causing organisms within a complex Number of genes required for resistance to disease Plant breeding has produced some tolerant/resistant varieties Limited effectiveness Resistant varieties only effective in reducing colonisation during crop growth After maturity, diseases such as Fusarium spp grow as saprophytes in stubble of all varieties Agronomic managements reduce disease inoculum Cultivation to bury stubble Stubble burning o Risk of erosion and loss of soil organic matter Crop rotations o But pathogens can survive several years in crop residues

5 Biocontrol An alternative approach Endophytic bacteria Live inside healthy plants Do not cause disease Mutually beneficial Are protected from Adverse environmental conditions Competition from other soil organisms Superior colonisation Actinobacteria Filamentous bacteria with complex & robust spore structures Produce a range of bioactive compounds, e.g. Antibiotics/antifungals Plant growth regulators

6 Collection and isolation of endophytic actinobacteria Isolated from healthy wheat plants in WA wheat belt Plant roots were surface sterilised cut aseptically to expose microorganisms inside the plant plated on agar medium selective for actinobacteria

7 More than 300 isolates of actinobacteria were screened for biocontrol capability

8 Biocontrol testing in vitro assay for antibiotic/antifungal production 300 isolates ranked according to degree of suppression in vitro RANKING ISOLATE Top 10 Rhizoctonia Pythium Take-all 1 MH 191 MH 60 MH MH 192 MH 192 MH 60 3 MH 122 MH 191 MH MH 60 MH 243 MH MH 243 MH 63 MH 73 6 MH 105 MH 73 MH 63 7 MH 73 MH 2 MH 64 8 MH 92 MH 128 MH 33 Some isolates suppressed multiple pathogens

9 Biocontrol of Pythium root rot in pot trials + PYTHIUM + MH 73 + PYTHIUM - PYTHIUM

10 Fusarium Crown Rot (CR): Infection & Consequences Stubble-borne disease caused primarily by Fusarium pseudograminearum Infection of crown and lower stem White heads

11 In vitro antifungal activity of actinobacteria against three Fusarium pseudograminearum strains Actinobacteria Isolate Suppression zone (mm) CS5642 CS5834 CS3427 MH MH MH MH MH MH a MH Presentation title Presenter name Page 11

12 Average % Stem Browning Biocontrol of Fusarium CR in Small Plant Assays Treatment Wheat (cv Wyalkatchem), F. pseudograminearum CS

13 Average % Stem Browning Consistent response across 2 cultivars with actinobacteria MH71 & MH Wyalkatchem Tamaroi Healthy Control Disease Control MH71 MH243 Treatment

14 Average % Stem Browning Glasshouse trial 8 weeks Disease Control 66b MH71 MH192 MH193 MH243 Treatment MH71 & MH243 reduced disease symptoms by 50% But infection rate of disease was poor Wheat (cv Wyalkatchem), F. pseudograminearum CS5642

15 Pot Trials

16 Average Stem Browning (%) Glasshouse trials - plants grown to maturity Average Stem Browning 10 l.s.d p=0.05 Healthy 9 Diseased Control 66b MH71 MH192 MH243 Treatment MH71 and MH243 reduced disease severity by 27% and 25% respectively

17 Testing actinobacteria metabolites for suppression of Fusarium MH60 Control MH243 1:2 1:10 1:100 1:1000 1:2 1:10 1:100 1:1000

18 Sclerotinia sclerotiorum in canola In vitro suppression of Sclerotinia sclerotiorum by MH243 Photo by DAFWA

19 Pot assays in growth room Actinobacteria suppress Sclerotinia in canola 8 days after infection Healthy control Diseased control Disease + bio-control MH243 Disease + bio-control MH71 Disease + bio-control MH192 Disease + bio-control MH60 Canola plants infected with Sclerotinia at 10 das; actinobacteria sprayed on at 9 dai

20 Pot assays in growth room Actinobacteria suppress Sclerotinia in canola 16 days after infection Healthy control Diseased control Disease + bio-control MH71

21 Testing actinobacteria metabolites for suppression of Sclerotinia MH60 Control MH243 1:2 1:10 1:100 1:1000 1:2 1:10 1:100 1:1000

22 Conclusion Actinobacteria isolated from within healthy wheat plants were screened for biocontrol capability More than 300 isolates were collected from the WA wheat belt A sub-set of these isolates suppressed multiple diseases in vitro and in planta Two actinobacteria isolates (MH71 and MH243) Strongly inhibited Fusarium pseudograminearum in vitro o Reduced crown rot severity in small plant assays by % 8 week pot trials by ~50% Pot trials taken to maturity by ~25% Strongly inhibited Sclerotinia sclerotiorum in vitro Protected canola plants in small plant assays Next steps are field trials for Fusarium crown rot suppression Delivery development based on mechanistic studies Presentation title Presenter name Page 22

23 GRDC Grains Research Update Thank you Questions?