Tsuga Immune Response

Tsuga Immune Response

==============================================================================
TOPIC: Tree, A Life Story; Tsuga canadensis fight back
http://groups.google.com/group/entstrees/browse_thread/thread/71238e57ab560859?hl=en
==============================================================================

== 1 of 3 ==
Date: Fri, Jan 25 2008 5:00 pm
From: "Valdmets, Lisa (MED US)"

Greetings ENTS,

A book suggestion, (and...) "Tree, A Life Story" by David Suzuki & Wayne
Grady. "This book is a biography of one tree, a Douglas-fir, but it
could be any tree -- .." "Rooted securely in the earth, trees reach
towards the heavens. All across the planet, trees --- in a wonderful
profusion of form and function -- literally hold the world together."

This morning as I was reluctantly ready to turn the book back in at the
library unfinished. Decided to take one more look where I had left
off.(about 2 weeks past due) I decided to open the book at the place I
had last marked, the chapter titled "Maturity" subtitled "Trees Fight
Back".

It tells about an experiment conducted in 1979 three groups of willow
trees (doesn't say which species) were planted in pots and placed in
sealed rooms, two groups in one room and the third group in another.
Half of the trees in the first room were infected with leaf-eating
caterpillars. After two weeks, the immune systems in the infected plants
had been cranked up to repel the caterpillar invasion, and so were the
immune systems in the uninfected trees in the same room; the trees in
the isolated room however, were unaffected. "Somehow the infested trees
in the first room alerted the other trees in that room -- and not by
mycorrhizal communication, because the trees were in pots. Some volatile
compound emitted by the infected group had set off a master switch in
their neighbors." (page 117)

Previous posts I have learned indicated that Tsuga canadensis is unaware
(no immune response) to the HWA. Have experiments been done to see if
non-native Tsuga species and/or those trees who are HWA resistant/immune
if they were introduced/placed with the "unknowing" and HWA infected
native Tsuga canadensis would communicate and then create an immune
response in Tsuga canadensis to the HWA??

Could test plots of non-native Tsuga HWA resistant trees be placed
and/or planted in proximity to healthy (and unhealthy) Tsuga canadensis
and determine if communication and/or an immune response could be
provoked?

Anyone know if this has been tried?

I look forward to a reply, thanks!

Lisa Valdmets, new to ENTS, not new to loving trees

== 2 of 3 ==
Date: Fri, Jan 25 2008 5:20 pm
From: "Edward Frank"

Lisa,

This is a very intriguing idea. I am not aware of it having been tried, maybe someone else can give a more definitive answer. The questions are whether or not the immune reaction could be transferred between two similar species, and if it is, is the response sufficient to prevent the death of the native hemlock species.

One place that might provide clues would be any place that had the different hemlock species planted together - a nursery, an arboretum, or commercial planting.

Ed

"I am not bound to please thee with my answers."
William Shakespeare

==============================================================================
TOPIC: Immune Response in Hemlocks
http://groups.google.com/group/entstrees/browse_thread/thread/71238e57ab560859?hl=en
==============================================================================

== 1 of 1 ==
Date: Wed, Feb 6 2008 11:12 pm
From: "Edward Frank"

ENTS,

Last week Lisa Valdmets posted the note below. I want to get some opinions on the idea presented. She notes that immune responses to pests are commonly transmitted from infested trees to nearby trees of the same species. These nearby trees respond with increased chemical response to the pest even if they have not yet been attacked. The Eastern Hemlock and Carolina Hemlock does not have any response, or at least enough of an immune response to fend off the HWA infestations. Chinese hemlocks and western hemlocks seem to be able to fend off these infestations through a chemical response mechanism. The proposition and question is whether in intermingled hemlocks of western and eastern hemlocks, if an immune response in western hemlocks might potentially trigger a stronger immune response in eastern hemlocks in the immediate area, so that they too would be more resistant to the HWA - in effect their needles would become less palpable or even harmful to the HWA?

1) Do any of you know of a site with intermingled western or Chinese, and eastern or Carolina hemlocks? These may be in ornamental plantings, or in an arboretum or similar setting.

2) If so how are the eastern or Carolina hemlock faring compared to others outside the immediate vicinity of these other species?

3) Does it appear that there may be a better immune response, or are they being selectively infested in the mixed stand?

I don't know the answer, and perhaps the suppositions are not viable, but it certainly seems like something that could be, and should be checked into amongst all of the investigations.

Ed Frank

==============================================================================
TOPIC: Immune Response in Hemlocks
http://groups.google.com/group/entstrees/browse_thread/thread/71238e57ab560859?hl=en
==============================================================================

== 1 of 5 ==
Date: Thurs, Feb 7 2008 4:42 am
From: Andrew Joslin

Check out this paper:
Temporal and spatial variation of terpenoids in eastern hemlock (_Tsuga
canadensis_) in relation to feeding by _Adelges tsugae
_

http://nrs.fs.fed.us/pubs/jrnl/2006/nrs_2006_lagalante_001.pdf
Description of of the study:

http://www.treesearch.fs.fed.us/pubs/19979
It's worth reading through the paper for many reasons. First off
there's a detailed explanation of the HWA life cycle. The study results
describe how HWA takes advantage of seasonal lulls in terpene production
by eastern hemlock to avoid ingesting these defensive compounds.
I'm not qualified to say so but it appears that the eastern hemlock has a
particular defense "profile" which is not flexible enough to
override the adelgid's well-timed feeding strategy. This is only part of
the picture, there are other critical factors such as specific terpenoid
compound variants or levels of those variants that may be unique to
eastern hemlock vs. HWA resistant western hemlock. The end result is that
the eastern hemlock is doing the best it can with the tools it has to
fight HWA.
Andrew Joslin
Jamaica Plain, MA

== 2 of 5 ==
Date: Thurs, Feb 7 2008 5:34 am
From: wades@comcast.net

Ed, Haverford College has a Pinetum that has intermingled species of Hemlock including Canadian, Carolina and Northern Japanese. There may be a Chinese Hemlock there too. HWA is present, the trees have not been treated to my knowledge. The natives are not grey and dying, but they are not healthy either. They also have the triple threat of elongated scale, mites and HWA. There were HWA on the non natives too.

Another Arboretum that has several kinds of Hemlock is Morris Arboretum in Philadelphia. I do not know the status of their trees, but I am sure you could contact Herb White there and ask?

Scott

== 3 of 5 ==
Date: Thurs, Feb 7 2008 5:38 am
From: "Will Blozan"

Andrew,

Remember, you are talking about two separate adelgids; Adelges tsugae
("ours") and a yet unnamed (?) western species. The relatively recent
findings have thrown a wrench in earlier studies.

Will

== 4 of 5 ==
Date: Thurs, Feb 7 2008 1:54 pm
From: "Valdmets, Lisa (MED US)"

Thanks Ed, ENTS

Anyone know of any research or study any known collections of Tsuga
canandensis with Tsuga sieboldii from Japan and Tsuga mertensiana from
west coast of North America??

referencing the "Temporal and Spatial Variation of Terpenoids in Eastern
Hemlock (Tsuga canadensis) in Relation to Feeding by Adelges tsugae. "
Of interest and note is "Of the 51 terpenoids, 28 were present in
amounts that averaged <0.1%, and these were not included in the
statistical analysis." over half, therefore as the paper goes on to
clarify "The importance of these low-level terpenoids is uncertain" and
"the PCA analysis does not consider the overall level of terpenoid in
the eastern hemlock"

uncertain

alternately of interest is more one of "plant neurobiology"

"plant immunity, plant memory and learning, plant-plant communication as
well as plant intelligence"

www.plantneurobiology.org <http://www.plantneurobiology.org/>

Plant Neurobiology describes a newly named, but also old and fascinating
field in plant biology addressing the physiological basis of adaptive
behavior in plants. Perhaps this field could be called "Sensory Biology
in Plants" or something similar. However, these names don't quite cover
topics like plant cytology and anatomy, adaptive plant behavior,
signaling and communication in symbiosis and pathogenesis, or newly
emerging topics like for instance plant immunity, plant memory and
learning, plant-plant communication, as well as plant intelligence.
Our choice of the term Plant Neurobiology is described in Brenner et al.
(2006) where we note some obvious analogies between classical
neurobiology and some aspects of the physiology of plants. For example,
plants have long been known to respond sensitively to environmental
stimuli by movement and changes in morphology, to be electrically
excitable, to display rapid electrical responses (action potentials) to
environmental stimuli, to synthesize numerous organic molecules that act
as neurochemicals in other organisms, and to use hormonal signaling
pathways to coordinate development, morphology and thus, accomplish
behavioral responses to environmental, communicative, and ecological
contexts.
One important goal of establishing a community for Plant Neurobiology is
to provide a venue for all interested biologists to explore complex
plant behavior utilizing all levels of experimental approach. Among our
symposia participants have been molecular geneticists, biochemists,
electrophysiologists, physiological ecologists, community ecologists,
mathematical modelers, plant designers, and even philosophers. Plant
Neurobiology will use the lens of integrated signaling, communication,
and behavior to integrate data obtained at the genetic, molecular,
biochemical and cellular levels with physiology, development and
behavior of individual organisms, plant ecosystems and evolution.
For a better understanding of the world around us, it is important that
we develop and share the growing understanding of plants as dynamic and
highly sensitive organisms. No longer can plants be viewed and portrayed
as passive entities merely subject to environmental forces, as
'automata'-like organisms based only on reflexes and optimised solely
for accumulation of photosynthate. With a fuller understanding of
signaling and communication within and among plants, it becomes clear
that these sensitive biological organisms actively and competitively
forage for limited resources, both above and below ground. In addition,
plants accurately compute their circumstances, use sophisticated cost
benefit analysis, and they take tightly controlled actions to mitigate
and control diverse environmental stressors. Plants also emerge as
capable of discriminating positive and negative experiences, and
'learning' from their past experiences. Plants use this cognitively
acquired information to update their behavior in order to survive
present and future challenges of their environment. Moreover, plants are
also capable of refined recognition of self and non-self, and are
territorial in behavior.
This Plant Neurobiological view sees plants as information-processing
organisms with complex communications of various types occurring
throughout the individual plant. What we need to find out is how their
information is gathered and processed, what routes do data take (if not
via 'nerves' sensu strictu), and how are adaptive responses integrated
and coordinated, how are these events 'remembered' in order to allow
realistic predictions of future using past experiences.
Last but not least, plants are as sophisticated in behavior as animals
but this potential has been masked effectively because it operates on
time scales many orders of magnitude slower than in animals. At the very
least, this quality should make it easier for experimental plant
scientists to uncover the mysteries of their neurobiological function
and behavioral responses.

== 5 of 5 ==
Date: Thurs, Feb 7 2008 2:43 pm
From: "Edward Frank"

ENTS,

Dave Orwig emailed me the following:

A quick reply to the query below, At the Arnold Arboretum, in Jamaica
Plain, MA, there have been dozens of underplantings of Chinese hemlock
(Tsuga chinensis) across hemlock hill. In some cases these 2 m saplings
are less than a 1m from a heavily infested eastern hemlock sapling. Not
a speck of HWA to be found on the chinensis, but the eastern hemlock is
dripping white with HWA. These have been there several years and there
appears to be no 'transferable' response or benefit to the eastern
hemlock. thanks DAVE ORWIG

I guess that pretty much kills this idea with regard to Chinese Hemlock.

Ed Frank

== 2 of 8 ==
Date: Fri, Feb 8 2008 9:15 am
From: "Joseph Zorzin"

I wonder if the Chinese Hemlock would be able to "escape" in much of the range of the native hemlock. If so, I wonder how the tree compares with the native species from the point of view of the wood industry.

Joe

== 3 of 8 ==
Date: Fri, Feb 8 2008 11:15 am
From: James Parton

Ed, Will, ENTS.

I wonder if the Chinese Hemlock could be hybridized with our native
species and be backcrossed with pure native trees and retain the
ternpenid characteristics that the Chinese trees have? The same
process is being used by the ACCF to breed a blight resistant American
Chestnut trees. Though not a 100 percent pure native tree it still
could save the native form and genetics of the original while keeping
the desired factors ( Blight resistance/High ternpenid levels ) of the
introduced trees. It may prove to save the A. Chestnut and could so
the native hemlocks.

James Parton.

== 4 of 8 ==
Date: Fri, Feb 8 2008 11:25 am
From: Andrew Joslin

This looks to be an important strategy towards preventing eastern
hemlock species extinction.
-AJ

== 5 of 8 ==
Date: Fri, Feb 8 2008 11:40 am
From:

A few years aog, I had read that attempts to produce hybrids with eastern hemlock were a failure, but were successful for the Carolina hemlock. Google helped me relocate the article:

http://www.treelink.org/joa/2002/july/06Bentz.pdf

The Chinese hemlock and all but one other Asian hemlock can't survive the cold in much of the hemlocks range. Of all the Asian adelgid resistanct hemlock species, only the Northern Japanese Hemlock (tsuga diversifolia) may be cold hardy enough to survive in most of the existing hemlock range. It's form and hardiness varies dependent upon seed source. Most U.S. nursery stock is from less cold hardy, smaller statured cultivated landscape varieties.

Paul Jost

== 6 of 8 ==
Date: Fri, Feb 8 2008 12:24 pm
From: Andrew Joslin

Reading the paper* on eastern hemlock terpenoid response to HWA (Adelges
tsugae) gave me a better understanding of the HWA life cycle. This brings
up a question. If HWA starts feeding in October-November what's the best
time of year to treat hemlock systemically with imidacloprid? What's the
uptake interval between soil injection or root drench and optimal levels
of imidacloprid where HWA feeds in the outer twigs?
Knowing that HWA starts feeding in the late fall to take advantage of low
terpenoid levels sheds light on why the southern hemlocks are being hit
so hard. In the northeast U.S. HWA must slow down or stop feeding when
very cold winter temperatures hit. It's possible that in more southern
locations the adelgid can continue feeding through the entire winter
causing greater stress on the tree and greater reproductive productivity
for HWA, possibly creating the explosive population effect seen in
southern hemlock forests. Obviously lack of winter kill of the
adelgid in the south is significant but enhanced winter feeding
opportunity may be a big part of the problem.
Which brings me to something else gleaned from the study. The authors
noted that after the HWA population peaks following initial infestation
the food supply is exhausted, extensive needle drop takes away the
feeding site. The HWA population crashes and an opportunity occurs for
the tree to refoliate. Will has mentioned this post infestation flush of
new foliage. The small numbers of HWA remaining then repopulate the tree
and start the attack cycle all over again. It looks like anyone studying
beetle or other biological controls has to be very discerning to separate
out post infestation refoliation caused by inherent HWA population cycles
and the actual effects of biological controls.
-AJ

== 7 of 8 ==
Date: Fri, Feb 8 2008 1:12 pm
From: "Will Blozan"

Andrew,

Very true about the refoliation. I have yet to get a satisfactory answer as
to how those folks heralding the success of the beetles can differentiate
(or substantiate) "natural" refoliation with reduced HWA loads from that
"caused" by the beetles. I have asked two researchers for data and have
received nothing to date.

Soil applications of imidacloprid are really slow to act and I haven't seen
an immediate impact on HWA regardless of season or purported "best" time of
application. It all depends on soil moisture, too.

Will

== 8 of 8 ==
Date: Fri, Feb 8 2008 2:10 pm
From: Andrew Joslin

Thanks Will. It sounds like spring makes sense to conservatively have a
chance to affect the fall HWA feeding period.
-AJ

Home