L6 - Biological

Question 1

what are the problems associated w/ bio control

Answer 1

• toxicity of bio control ages
• evolution of resistance
• variability of success

Question 2

example of variability of success

Answer 2

Pseumonas fluoresens only sucessful in 6/10 trails in combatting take all disease

Question 3

biological organisms should be (4)

Answer 3

• good at colonising
• good at colonising rhizospshere
• adapted to a disturbed cultivated environment
• survive adverse conditions (prod spores/sclerotia)

Question 4

in 2005 …. new bio agents for plant path reg

Answer 4

41 - majority true fungi/bacteria

Question 5

Current products include (2)

Answer 5

1. seed treatments - Short term

2. horticultural approches

Question 6

5 mechanisms of Biological control
CAPIC
CAPIC
CAPIC

Answer 6

1. competition
2. antibiosis
3. parasitism
4. induction of host resistance
5. cross-protection

Question 7

adv of usign antibiosis

Answer 7

can detect in soil v little amounts

80mgha-1

Question 8

Crown Gall dis is produced by……

Answer 8

Agrobacterium tumefaciens

Question 9

Crown Gall bio agent is

Answer 9

Agrobacterium radiobacter strain K84

Question 10

Crown Gall

antibiotic produced is
this causes
affects

Answer 10

Agrocin 84

inhibits leucyl tRNA synthesis

A. tumefacies only sensitive
-very specific

Question 11

Crown Gall

issue w/ biocontrol

Answer 11

Res gene + product are on the same plasmid in A. radiobacter
–> can transfer to A. tum and it would be resistant.

Solve - mutant which cant transfer plasmid - K1026 - used in australia NOGALL

Question 12

what is suppressive soils

Answer 12

the bacteria causing the disease is constantly present at low levels despite inoculum present and environment fav

Question 13

Take All disease caused by…. + infects

Answer 13

Gaeumannomyces graminis

Wheat

Question 14

Take all control by….

Answer 14

Pseudomonas fluorescens

strain Q8r1-96

Question 15

Take all disease builds up in severity but levels off - expand

Answer 15

builds up year on year (gaeumannomyces graminis) but starts to decline at 4-5 years

famers should

a) short rotation
b) continuous wheat

example of suppressive soils with natural pseudomonas fluorescens levels building

Question 16

Take all

antibiotic is

Answer 16

Pseudomonas fluorescens

2,4-DAPG

Question 17

Take all

issue with antibiotic

Answer 17

• non specific 24DAPG can effect plants + animals
• affects multiple process

( good - can induce resistance in arabidopsis

Question 18

Take all

antibiotic strains associate preferentially with specific plant species e.g.

has been modified how

Answer 18

wheat 
or Fusarium (peas)

into of PCA to Q8r1-96 strain - suppress root rot also

Question 19

Damping off /Root rot caused by

Answer 19

Pythium ultimum

Question 20

Damping off /Root rot control agent

Answer 20

Pseudomonas fluorescencs CHAO strain

Question 21

Damping off /Root rot

produces

Answer 21

2,4-DAPG

+ pyoluteorin

Question 22

Damping off /Root rot

results of engineering

Answer 22

engineered Pseudomonas fluorescencs CHAO strain to enhance pyoleutorin production:
- increased control of cucumber damping
BUT
strongly reduced growth of cress and sweetcorn in absence of pathogen

Question 23

improvements of bio control (4)

Answer 23

1. improve environ for bio agents
2. obtain better control agents
3. combo of organisms used
4. combo w. fungicide

Question 24

example of where bio and chem control together

Answer 24

De Curtis 2019

study used both on peaches and apricots against brown rot of stone fruits

Question 25

another DSS of potato late blight

Answer 25

VNIIFBlight

Question 26

white rust study

Answer 26

biological and chemical fungicides to control white rust in chrysanthemum

both was more effective than a single method

Rahardjo 2015