fusarium sacchari, the cause of pokkah boeng in sugarcane is a

Fusarium sacchari, the Cause of Pokkah Boeng in Sugarcane is a Colonist of Wild Rice

T. Petrovic, L.W. Burgess, I. Cowie & P. Harvey

CSIRO. F. sacchari, a colonist of O. australiensis

Fusarium Species in Natural Australian Ecosystems

• Source of:• Undescribed species• Known crop pathogens• Potential pathogenic genotypes

• F. thapsinum, F. proliferatum, F. verticillioides, F. sacchari –Indigenous Sorghum species (Walsh, 2007)


Wild Oryza Ecosystems in Australia

• New Guinea & surrounds – possible center of Oryza origin

Australia - 4 wild Oryza speciesO. australiensis, O. meridionalis - endemicO. rufipogon - nativeO. minuta - introduced

• Genetic ‘purity’ & no genetic erosion

Wild Oryza species

Cultivated rice


Fusarium fujikuroi on Wild Oryza in Australia?

Hypothesis:• Is F. fujikuroi, cause of Bakanae disease of wild and cultivated rice in Asia,

associated with wild rice species in AU?

Endemic – O. australiensisObjectives:• To recover Fusarium species from a population of wild rice• Pathogenicity: primary (wild rice) vs. potential hosts (rice, sorghum & maize)


0

5

10

15

20

25

30

35

40

F. aywerte FIESC* FIESC* F. longipes F. nygamai F. sacchari

Recovery of Fusarium spp. from StemsA

bund

ance

(%)

• 92 isolates / 6 morpho-species / ENTO code #

*FIESC – F. incarnatum-equiseti Species Complex


Morphology of Fusarium sacchari

A

B

C

D F

E


Sequencing & Parsimony Analysis

10

AF160312ENTO64

NRRL31649EF452969HM347125FD 01770N

ENTO65ENTO67ENTO75ENTO68ENTO70ENTO79ENTO81ENTO84ENTO86ENTO71

GQ915509ENTO106ENTO110ENTO120ENTO156

ENTO149ENTO103ENTO108ENTO135ENTO137

ENTO132ENTO133FD 01628FD 01623

GU116581GQ505620GQ505617GQ505596GQ339789GU116576

ENTO92ENTO98ENTO114ENTO122

GQ505671GQ505667GQ505664

GQ505637GQ505672GQ505670GQ505638

ENTO90AF160273FD 01301HM347121

ENTO89ENTO87EF107154EF107153

100 94

9165

6364

100

100

96

100

100

95

84100

98

97

56

98

100

10091

96

8574

100

99

8674

F. sacchari

F. longipes

Incarnatum clade

Equiseticlade

F. nygamai

F. aywerte

• Sequencing – EF-1α

• ENTO sequences

• Reference sequences from Fusarium-ID data base


Characterizing Fusarium sacchari - I

50

100

100

81

75

100

77

5465

100

100

30 40 50 60 70 80 90 100

• Dominant AFLP markers

• ENTO F. sacchari strains (24)

• Reference strains / testers (2)

• DICE similarity


• Mating type analysis – PCR based• 15 MAT-1 : 9 MAT-2

• Sexual compatibility tests with F. sacchari tester strains• 24 male : 1 female fertile

• oozing perithecia & viable ascospores

Characterizing Fusarium sacchari - II

RBG3585 x ENTO 66 (MAT-2) RBG3584 x ENTO 80 (MAT-1) ASCOSPORES


Pathogenicity – Wild Rice & Potential Hosts

• 4 hosts x 3 isolates (wild rice, rice, sorghum & maize)• Seed coating – macroconidial suspension 3x106 spores/ml• Re-isolation – wild rice & rice (6wks); sorghum & maize (3wks)

Wild rice - Control Rice - Control


Pathogenicity – Wild Rice & Potential Hosts

0

10

20

30

40

50

60

70

80

90

100

WILD RICE RICE SORGHUM MAIZE

Control ENTO 65 ENTO 68 ENTO 71

% g

erm

inat

ion

• Reduction in germination and seedling growth of wild rice and rice

Fpr. < 0.001, df = 9


Effect of F. sacchari on Vegetative Growth of Rice (3wks)

Control ENTO 65 ENTO 68


Discoloration of Tissue on the Potential HostsRICE – mesocotyl & primary root

MAIZE – crown root

SORGHUM – mesocotyl & crown root


Percentage Re-isolation – Wild Rice & Potential Hosts%

re-is

olat

ion

0

10

20

30

40

50

60

70

80

WILD RICE RICE SORGHUM MAIZE

Control ENTO 65 ENTO 68 ENTO 71


Conclusions

• F. fujikuroi (Bakanae disease of rice) – not associated with wild rice

• F. sacchari (Pokkah Boeng of sugarcane) – colonist of wild rice• Species identification (morphology, EF-1α seq., AFLP, crossings)• Pathogenicity:

• Reduction in seed germination of wild rice and rice• Effect on vegetative growth of rice seedlings• YES – colonist of sorghum, maize and rice


Further Work

• Pathogenicity tests • quantify vegetative growth inhibition in rice • monitor F. sacchari colonization through life cycle of wild rice & rice

• Population genetic studies• screen progeny derived from 24 crosses• identify co-dominant markers• use co-dominant markers to study populations (natural vs. agricultural)

• Sampling more populations of O. australiensis

Contact UsPhone: 1300 363 400 or +61 3 9545 2176

Email: [email protected] Web: www.csiro.au

Thank you

Acknowledgements

Dr Gupta Vadakattu (CSIRO Ecosystem Sciences) for microscopy expertise

Dr Sally Dillon (ATCFGC) provided untreated O. australiensis, maize & sorghum seeds

Dr Peter J. Snell (NSW DPI, Yanko) provided rice seed

CSIRO Ecosystem SciencesDr Tijana PetrovicResearch Project Officer

Phone: 08 8303 8559Email: [email protected]: www.csiro.au/ces

Work is supported by CSIRO’s Sustainable Agriculture National Research Flagship


Re-isolation from hosts tissues

HOST Primary Root

Crown Root

Mesocotyl Crown Stem 1st

node

WILD RICE + + +

RICE + + ++ ± -

SORGHUM +++ ++ +++ ++ +

MAIZE ++ ++ +++ + -

Not done% re-isolation: Absent (-), Low (+), Moderate (++), High (+++); re-isolated in one treatment (±)

fusarium sacchari, the cause of pokkah boeng in sugarcane is a

Documents