Hello Tim!

thank you for the article. The last time I reviewed this, quorom sensing was 
not described for E. amylovora.

Vincent

Le 18 août 2015 à 17:23, Smith, Timothy J 
<smit...@wsu.edu<mailto:smit...@wsu.edu>> a écrit :

Re: virulence of E. amylovora.  Here is another good (in depth) article.

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4490474/

best regards,

Tim Smith


From: 
apple-crop-boun...@virtualorchard.net<mailto:apple-crop-boun...@virtualorchard.net>
 [mailto:apple-crop-boun...@virtualorchard.net] On Behalf Of Smith, Timothy J
Sent: Tuesday, August 18, 2015 1:17 PM
To: Apple-crop discussion list 
<apple-crop@virtualorchard.net<mailto:apple-crop@virtualorchard.net>>
Subject: Re: [apple-crop] Looking for comments on fire blight management

Re:  The bacteria (in the hypanthium) need to thrive in the nectary in order to 
reach numbers sufficient to switch on their virulence. Once this is 
accomplished you have an infection.

Do you have a good reference for me on this specific topic? When I reviewed the 
literature, I only found a few things from Pusey. This might explain some cases.

Hi Richard,

Yes, bacteriologist have been dropping the term “quorum sensing” over the past 
few years, which is a trait within both pathogenic and beneficial bacteria that 
allows them to be non-virulent when in low numbers, then, when they sense when 
numbers are sufficient to overwhelm the host, they all “switch on” their 
virulence, or if beneficial, the next action they are building up to.  This may 
allow them to avoid triggering host defense mechanisms until it is too late for 
the plant to successfully defend itself.

Look on Google for that term “Quorum sensing”  + Erwnia amylovora and you will 
find some good recent journal articles.

Try those below for a start.

https://en.wikipedia.org/wiki/Quorum_sensing<https://urldefense.proofpoint.com/v1/url?u=https://en.wikipedia.org/wiki/Quorum_sensing&k=EWEYHnIvm0nsSxnW5y9VIw%3D%3D%0A&r=VR1vaGJPOzxhk9dUVIL5%2Bg%3D%3D%0A&m=jW7ergoT5LqD39LktaREL2bgAhj7venJm67AYoMtfoI%3D%0A&s=030042055b8c2df784ceff8c21df217091314157e37d12539e4cc7a4c600bfb0>

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1082838/<https://urldefense.proofpoint.com/v1/url?u=http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1082838/&k=EWEYHnIvm0nsSxnW5y9VIw%3D%3D%0A&r=VR1vaGJPOzxhk9dUVIL5%2Bg%3D%3D%0A&m=jW7ergoT5LqD39LktaREL2bgAhj7venJm67AYoMtfoI%3D%0A&s=de38e438a398996dab0c9c6a38d5316c3526d9a981b0b0f5f60b8c009e1aa56f>


http://www.ncbi.nlm.nih.gov/pubmed/17092294<https://urldefense.proofpoint.com/v1/url?u=http://www.ncbi.nlm.nih.gov/pubmed/17092294&k=EWEYHnIvm0nsSxnW5y9VIw%3D%3D%0A&r=VR1vaGJPOzxhk9dUVIL5%2Bg%3D%3D%0A&m=jW7ergoT5LqD39LktaREL2bgAhj7venJm67AYoMtfoI%3D%0A&s=6010e2c1671af0092105563ed81394abfad76ed01012d04e7b230ef89c997ba2>





From: 
apple-crop-boun...@virtualorchard.net<mailto:apple-crop-boun...@virtualorchard.net>
 [mailto:apple-crop-boun...@virtualorchard.net] On Behalf Of Weinzierl, Richard 
A
Sent: Friday, August 14, 2015 2:27 PM
To: Apple-crop discussion list 
<apple-crop@virtualorchard.net<mailto:apple-crop@virtualorchard.net>>
Subject: Re: [apple-crop] Looking for comments on fire blight management

U of I Kane County Extension Office, 535 South Randall Road, St. Charles, IL

Rick


From: 
apple-crop-boun...@virtualorchard.net<mailto:apple-crop-boun...@virtualorchard.net>
 [mailto:apple-crop-boun...@virtualorchard.net] On Behalf Of Vincent Philion
Sent: Friday, August 14, 2015 12:49 PM
To: Apple-Crop 
<apple-crop@virtualorchard.net<mailto:apple-crop@virtualorchard.net>>
Subject: Re: [apple-crop] Looking for comments on fire blight management

Hi Tim! nice to read you!

 I think there are more sources of fire blight bacteria in the general 
environment in the northeastern USA due to your woodlots and forests (with 
feral apples and native hosts such as Hawthorne)  as contrasted with the 
treeless conditions around many eastern Washington orchards.

I agree! But still is fascinating to see whole areas without FB and others with 
FB, despite similar weather.

We often make “false positive” predictions because of this = conditions are 
great for FB, but not FB develops because bacteria are simply not there. We 
have nice qPCR data throughout bloom to prove it.

 The bacteria (in the hypanthium) need to thrive in the nectary in order to 
reach numbers sufficient to switch on their virulence. Once this is 
accomplished you have an infection.

Do you have a good reference for me on this specific topic? When I reviewed the 
literature, I only found a few things from Pusey. This might explain some cases.

We can learn a great deal about interpreting models by looking at the weather 
data around the time that we are fairly certain that isolated infection events 
occurred.  We can also look at when expected infections did not occur.   It 
would be very helpful to me if any of you would share weather data including 
rainfall, hourly temperature (or daily temps) and especially leaf wetness 
readings.  Please send data that covers days from first bloom to about 3 to 4 
weeks after petal fall.  Excel files are a real time saver.

We’re Also looking for the same type of data…!

Vincent
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