This document summarizes the results of a molecular re-evaluation of Phytophthora species isolated from natural ecosystems in Western Australia over 30 years. It was found that many isolates previously identified by morphology do not match the DNA identification. At least seven new Phytophthora species were discovered that are genetically distinct from currently described species. Several known Phytophthora species were also recorded for the first time in Western Australia. Further research is needed to understand the threat posed by these new species to biodiversity and determine factors like their host range, distribution, and whether any are introduced or hybrid species.

1. Molecular re-evaluation of
Phytophthora species isolated during
30 years of vegetation health
surveys in Western Australia
Mike Stukely, Giles Hardy, Dianne White, Janet Webster,
Juanita Ciampini and Treena Burgess

2. Jarrah Forest plain
Northern sand
Swan Costal Plain
Black gravel site
Fitzgerald National Park

3. Impact of Phytophthora cinnamomi on plant species
in Western Australia
Direct Impacts
• Out of 5710 described species in the South-West Botanical Province
• 2285 species susceptible (40%)
• 800 highly susceptible (14%)
Indirect Impacts
• Loss of biomass Phytophthora is listed as a
‘KEY THREATENING PROCESS’
• Loss of litter
to Australia’s Biodiversity by
• Loss of refugia for fauna Commonwealth Government
• Loss of food resources
• Increased exposure
• Loss of pollinators
• Loss of nesting sites

4. Dieback mapping and vegetative health surveys
•For over 30 years aerial photography has been used to map the extent
of disease in WA
•Many areas are uninterpretable aerially and ‘Dieback Interpreters’ are
sent in to ground truth
•They are trained to recognise susceptible indicator species. First
indication of the presence of P. cinnamomi is the death of susceptible
indicator species from the families Proteaceae, Epacridaceae,
Dilleniaceae, Xanthorrhoeaceae, Fabaceae.
•Usually ground truth areas of native vegetation due to be logged
•Samples are taken (usually soil from rhizosphere of dying plants) and
sent to vegetation heath service (VHS)
•Soils are baited with cotyledons of Eucalyptus sieberi
•After 5(-10) days cotyledons are examined and plated onto selective
media
•About 15% of phytophthora isolates are not P. cinnamomi

5. Phytophthora Management Map
Disease-free
Uninterpretable
Phytophthora infested
Green = Dieback free; Purple = Uninterpretable; Red = Infested

6. Phytophthora species in natural ecosystems in WA
•Until recently indentified only by morphological features
P. citricola
P. megasperma
P. cryptogea
P. drechsleri
P. nicotianae
P. boehmeriae
•Other species are found in nurseries and in horticulture
•Over the past 2 years we have been conducting a molecular re-
evaluation of Phytophthora spp. in natural ecosystems in WA
•Over 250 isolates so far examined
•Sequenced ITS region and constructed molecular phylogeny

7. 97 P. inundata
100
91 100 P.sp.6 = P. sp. personii
100 P.sp. 10
100 P.sp. 7
100 P.sp. 3
100 Group 6
97 P.sp. 8
77 100
P.sp. 11
66 100 P. megasperma
100
97 P. gonapodyides
99
P. sp. hungarica
P. sp. sylvatica
100
P. sp. asparagi
P. inflata
98
67 P. citricola
95 P.sp. 4
100
96
P. tropicalis
100
100 P. capsici Group 2
56
53 100 P. multivesiculata
98 100 P. alticola
100
100 100 P. bisheria
100 P.sp. 2
100
52 100 P. arecae Group 4
100
100 P. frigida
100
95
100 P.sp. 1
78
100 P. nicotianae Group 1
100 P. cactorum
100
Group 3
P. ilicis
87
100 P. katsurae
Group 5
100 P. cambivora
85
100 P. cinnamomi Group 7
100 100
P. melonis
100 P. sp. niederhauseria
93 P. sojae
100 P. ramorum
71 100
100 P. drechsleri
100
P. cryptogea Group 8
98
87 P.sp. 5 = P. cryptogea
100 P. kernoviae
100
100
P. boehmeriae
94 P. captiosa Group 9
100
100 93 P. fallax
100
P.sp. 9
5 changes

8. 96
P. humicola
93
P. inundata
100
100 P. sp. personii
91
64 TCH 009 - P.sp. 10
68
VHS 17779 - P.sp. 10
100 Phytophthora sp. P462 AF541911
Phytophthora sp. P532 DQ512952
88
Phytophthora sp. PgChlamydo
82
P. gonapodyides
Phytophthora sp. P1049 AF541904
100 Phytophthora sp. P896 AF541903
VHS 9854 - P.sp. 7
100 DCE 68 - P.sp. 7
DDS 3599
91
P.sp. 3
54
VHS 16108
67 VHS 17350
96 97
80 P.sp. 8
82 VHS 16115
100 52 51
65
77 P.sp. 11
VHS 5185
100
P. megasperma
88
100
P. hungarica
P. sylvatica
100
100
P. sp. asparagi
100
P. citricola
100
P. nicotianae
P. boehmeriae
5 changes

9. Often the morphological and molecular
identifications do not match
Isolates Morphology DNA
Many P. citricola P.sp.4
Many P. citricola P.sp.2
All tested P. drechsleri P.sp.3/8
Two P. megasperma P.sp.7
Many P. megasperma P.sp.9
TCH009 P. megasperma var sojae P.sp.10
VHS17183 P. megasperma P. megasperma
All tested P. nicotianae P. nicotianae
All tested P. cinnamomi P. cinnamomi
All Tested P. cryptogea P. cryptogea

10. Phytophthora species in natural ecosystems in WA
•New records for WA
P. inundata
P. gonapodyides
P. sp. asparagi
P. sp. niederhauseria
P. sp. personii
•At least seven new Phytophthora species which are genetically
distinct to currently described species

11. Phytophthora species in natural ecosystems in WA
Species No. Host species
P. sp. 1 10 B. menziesii, B. littoralis,
B. attenuata, B media
P. sp. 2 21 Eucalyptus marginata, Corymbia calophylla, B. grandis,
Dryandra squarrosa, Patersonia xanthina
P. sp. 3 15 E. marginata, B. attenuata,
B. grandis; Pinus radiata (plantation)
P. sp. 4 64 E. marginata, B. attenuata, B. grandis, B. littoralis, B.
menziesii, B. prionotes, Conospermum sp., Leucopogon
verticillatus, X. gracilis, Podocarpus drouyniana,
Patersonia sp., Bossiaea sp., Gastrolobium spinosum;
Pinus radiata (plantation)
P. sp. 7 4 X. preissii; Pinus radiata (plantation)
P. sp. 8 3 Soil and water baits – native forest
P. sp. 9 23 B. attenuata, B. baxteri, D. cirsioides, D. falcata, A.
cuneata, Isopogon sp.; Pinus radiata (plantation)
P. sp. 10 2 B. prionotes, B. grandis
P. sp. 11 2 Banksia sp., X. preissii

15. Significance of new phytophthora species
•Do they pose a threat to biodiversity?
•If yes, then management strategies will be developed
•Need to investigate
host range/pathogenicity
distribution
factors affecting spread
•Are these species introduced?
•Are any of these species hybrids?