Erwinia, Brenneria, Pantoea, and Pectobacterium (facultative anaerobes)

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Erwinia, Brenneria, Pantoea, and
Pectobacterium (facultative anaerobes) Gener
al 1. Heterogenous generally classified into
4 groups 2. Numerous commodities (apples,
potatoes, cricket bat trees, cereal crops,
etc.)
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Unusual Erwinias a. E. uredovora (synonyms E.
ananas pv.uredovora Pantoea ananas) parasite of
rust fungi Biocontrol??? b. E. tracheiphila
and E. stewartii - overwinter in beetles.
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Wide range of plant diseaseswilts, blights,
cankers, dieback, leaf and fruit
spotsdiscoloration of woody tissue Pantoea
agglomerans (E. herbicola) human pathogen.
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• Pantoea agglomerans (syn. E. herbicola)
• Usually a saprophyte
• Epiphytic on many plants (leaves and flowers),
• Problem in isolating E. stewartii from corn
• Often found associated with fireblight (E.
  amylovora)
• Reduces fireblight severity.

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4. Identification 1. Gram-negative 2.
Peritrichously flagellated, except E.
stewartii 3. aerobic or facultative anaerobe
(ex. carotovora pv. atroseptica) 4. optimum
growth - varies so much within genus E.
carotovora pv. atroseptica (about 20C) E.
carotovora pv. carotovora (28C)
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5. oxidase negative catalase positive 6. GC
50-58 7. Diagnosis disease symptoms, colony
morphology on specific media ferments
carbohydrates - Erwinia spp. Is the likely
pathogen. 8. Selective media Miller Schroth
CVP.
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Taxonomy A. Amylovora and Brenneria
groups a. cause dry rots or wilt symptoms b. no
pectic enzymes or yellow pigments
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c. examples E. mallotivora small tree in
Japan B. nigrifluens bark canker of walnut B.
quercina drippy nut of oak (California) B.
quercinia pv. rubrifaciens phloem canker of
walnut - (California) E. alni Bark cankers of
alder (Alnus) in Italy.
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B. salicis watermark disease of willow,
discolors wood used to make cricket bats
(England). E. billingiae stem cankers,
blossoms and immature fruits primarily from
rosaceous trees. Often in association with
plant pathogens considered secondary invaders.
Recently described species - named after Eve
Billing.
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E. amylovora 1. Fireblight disease of apples,
pears, (Rosaceae) etc. 2. Serious throughout the
world bacteria are commonly resistant to
antibiotics (Streptomycin Oxytetracycline).
3. Flowers are most common site of infection.
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Fireblight Apple Erwinia amylovora
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• epiphytic populations on stigma precedes
  infection. Warm temps during bloom (gt15 C)
• pollinating insects promote establishment and
  growth of bacteria. Epiphytic bacteria also grow
  on anthers and hypanthium (nectary).
• Stigmas protected, nutrient rich, hydrated
  environment Epiphytes (E. a) may colonize at
  populations greater than 106 CFU/stigma.
• 5. E. amylovora colonizes stigma, cells are
  washed to the hypanthium (nectarthodes) where
  infection occurs. Sugar conc. in nectar may
  reach 60. After rain, may be lt2.

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6. E. amylovora cells detectable in blossoms
after temp reaches 15 C (60 F). Accumulated
degree hours above 18.3 C (65 F) resulted in two
predictive models MARYBLYT and
COUGARBLIGHT MARYBLIGHT calculates degree hours
above 18.3 C and a threshold value of 110
cumulative degree hours from blossom pink stage.
Most popular of the models. COUGARBLIGHT Sums
degree hours above 15.5 C for 4 days.
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Fireblight Apple Erwinia amylovora
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Fireblight Apple Erwinia amylovora
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Fireblight Apple Erwinia amylovora
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Fireblight Apple Erwinia amylovora
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Fireblight Apple Erwinia amylovora
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Fireblight Apple Erwinia amylovora
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7. Biological control Suppression of fire blight
by antagonistic bacteria. Pseudomonas
fluorescens strain A506 ( BlightBan
A506). Erwinia herbicola strain C9-1 (Pantoea
agglomerans, EHC9-1) received an experimental
permit from EPA in 1998. A)To be effective,
stigma must be colonized at 105 to 106 CFU.
Competitive exclusion is probably the mode of
action.
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A506 suppresses growth 72 hr before inoculation
with E. amylovora but not when co-inoculated at
the same time. 40-60 reduction in blossom
blight with 2 application of A506. EhC9-1
produces two antibiotics that inhibit E.
amylovora. Also competes for sites and nutrient
sources. Treatment with EhC9-1 reduced fire
blight between 50-80 similar to antibiotic
sprays.
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Recommendation Apply bacterial antagnostics
twice between 25 and 90 bloom. Insects, mostly
bees, disseminate antagonistic bacteria from
colonized to noncolonized blossoms. Erwinia
herbicola (Eh1087), an epiphyte (New Zealand)
produces a B-lactam antibiotic. In experimental
stage of development.
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f. E. tracheiphila (Bacterial wilt of
cucurbits) serious problem in cucurbits
muskmelon and cucumbers are very susceptible
Squash, moderately susceptible, pumpkin,
moderately resistant, watermelon, nearly immune.
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Overwinters and vectored by 12-spotted and
striped cucumber beetles. Bacteria in feces -
enter through wounds. Control control beetles
by spraying insecticides. Diagnosis cut stem -
viscous strands may extend upwards of 4-6 inches.
Pull strands over petri plate. Difficult to
keep in culture except in lyophil
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Bacterial wilt Muskmelon E. tracheiphilia
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Bacterial wilt Muskmelon E. tracheiphilia
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Bacterial wilt Muskmelon E. tracheiphilia
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Bacterial wilt Muskmelon E. tracheiphilia
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Bacterial wilt Muskmelon E. tracheiphilia
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Bacterial wilt Muskmelon E. tracheiphilia
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Bacterial wilt Squash E. tracheiphila
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Bacterial wilt Squash E. tracheiphilia
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Erwinia pyrifoliae Recently described pathogen
from Asian pears in Korea. Very similar to E.
amylovora (the same ?).
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B. Herbicola group a. yellow pigments
(usually) b. opportunistic pathogens of man many
are nonpathogenic plant epiphytes c. examples
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• E. ananas pv. ananas (Pantoea citrea) Pink
  disease of pineapple
• Symptoms not recognized until fruit is cored and
  canned.
• Diagnosis sample cans of fruit
• Zero tolerance positive diagnosis entire lot
  must be destroyed (lot 37,000 cans).

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E. ananas pv. uredovora parasite on urediospores
of leaf rust (Puccinia graminis) of wheat. Needs
to be more throughly researched - possible
biocontrol for leaf rust?
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E. herbicola pv. herbicola galls on Gypsophila
(baby breath) E. herbicola pv. milletiae
Wisteria tree, mostly galls (Japan). Enterobacter
pyrinus Brown leaf spot disease of pear trees
(Korea).
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E. stewartii - (syn P. stewartii or P. s. subsp.
stewartii)

Stewarts wilt of corn (political disease / trade
barrier)
Vector Corn flea beetle - Bacteria overwinter in
insect
Beetles are very efficient vectors
Imidacloprid seed treatment reduced flea beetles
and disease
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Maize and sweet maize (principal hosts) severe
losses to corn crop in 1930's North, Central,
South America, Europe and Asia Seedborne - but
rare. Seed transmission (95 CI) was 0.22 or
about 2 positive plants from 1,000 E. stewartii
infected kernels.
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• Excellent resistance in most hybrids - Since
  1995, Stewarts wilt has increased in Kansas and
  other areas in the corn belt.
• Disease forecasting based on average winter
  temperature
• Cold winter - fewer beetles survive.
• Sum of mean temperatures for December, January
  February
• gt 100 C - - large number of insects survive.
• Cold winters Sum of mean temperatures lt 85 C.

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A "BIG" problem in international shipments of
seed and feed grains Over 100 countries require
a phytosanitary certificate that grain is free of
Stewart's wilt. Political disease of corn. Also,
a false positive diagnosis in sorghum is a BIG
concern.
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Stewarts wilt Corn Pantoea stewartii
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Stewarts wilt Corn Pantoea stewartii
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Pantoea stewartii subsp. indologenes (indolum,
indole gennao, to produce Strains are
Athought_at_ to cause leaf spot on foxtail and pearl
millet. Only 8 strains tested and were
received as E. herbicola.
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Carotovora group Erwinia to Pectobacterium
(Hauben, L., et al (1998). Syst. Appl.
Microbiol 21384-397.
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Produce pectolytic enzymes macerate cell walls of
host plants (mainly soft rots in
storage). Pathogenicity bacteria produce
exoenzymes pectate lyase (Pel), polygalacturonas
e (Peh), cellulase (Cel), protease (Prt) -
degrade cell walls of plants.
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Great economic importance both storage and
in-field losses
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Predisposing causes such as frost and mechanical
injury, other bacteria and fungi may enhance soft
rot infections. e.g. blackleg of potatoes in
Montana
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E. carotovora pv. carotovora many hosts
affected warm temperature organism, many
serotypes (30?), commonly found in soil.
Causes soft rot of potato tubers and pathogenic
to numerous crops. Important in storage of
vegetables.
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E. carotovora pv. atroseptica Important in
blackleg disease of potato (cool regions -
20C). An important disease of potato.
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E. chrysanthemi many hosts, warm temperature
organism. Bob Dickey Six serovars of E.
chrysanthemi
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May produce dark blue pigment on YDCA after 5-10
days of growth. Caution identification of
atroseptica and carotovora may be an artifact of
incubation temperature.
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E. rhapontici crown rot of rhubarb pink seed of
wheat (England). Dubious report as to host
range
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E. cypripedii bacterial brown rot of orchids
no pectolytic enzymes reported.
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Control a. Sanitation virus-free program in
Montana b. cultural practices avoid
overwatering, bruising perishable commodities,
etc. c. irrigation water bacterial stalk rot of
corn.
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Atypical Erwinias a. no plant
pathogens b. group of miscellaneous bacteria
whose taxonomic position is doubtful or has not
been determined
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Erwinia nimipressuralis described as "wetwood"
disease of elm. Now placed in genera
Enterobacter. Found on KSU campus Look for pipes
inserted into elm trees.
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Future More changes in taxonomy of Erwinia,
Pantoea Pectobacter, Brennaria, and
Enterobacter. 16S rRNA gene sequences powerful
computers to perform phylogenetic analysis.
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Black leg Potato E.c. var. atroseptica
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Blackleg Potato E.c. var. atroseptica
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Blackleg Potato E.c. var. atroseptica
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Blackleg Potato E.c. var. atroseptica
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Blackleg Potato E.c. var. atroseptica
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Blackleg Potato tuber E.c. var. atroseptica
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Bacterial soft rot Sorghum E.c. pv carotovora
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Stalk rot Corn E.c. pv. chrysanthemi
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Stalk rot Corn E.c. pv. chrysanthemi
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Foot rot Rice E.c. pv. chrysanthemi
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Foot Rot Rice E.c. pv. chrysanthemi
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Bacterial palea browning Rice E.c. pv.
herbicola
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Bacterial palea browning Rice E.c. pv.
herbicola
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Cabbage production California March 1975
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Bacterial soft rot Cabbage - Erwinia
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Lettuce transplants California March 1975
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Lettuce E. carotovous pv. carotovous
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Cactus
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Cactus Healthy and Inoculated
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Cactus Inoculated understock
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Cactus - Infected