scholarly journals The Role of Autumn Infections in the Progression of Fire Blight Symptoms in Perennial Pear Branches

Plant Disease ◽  
2003 ◽  
Vol 87 (9) ◽  
pp. 1077-1082 ◽  
Author(s):  
D. Blachinsky ◽  
D. Shtienberg ◽  
D. Oppenheim ◽  
M. Zilberstaine ◽  
S. Levi ◽  
...  
Keyword(s):  
Fire Blight ◽  
Shoot Growth ◽  
Erwinia Amylovora ◽  
Symptom Expression ◽  
Host Phenology ◽  
Final Length ◽  
Symptom Progression ◽  
In Fire ◽  
The Relationship

The role of autumn infections in the progression of fire blight (caused by Erwinia amylovora) symptoms in perennial pear branches was studied in orchard-grown trees in Israel. The extent of symptom progression and the final length of fire blight cankers in perennial branches were variably affected by the vigor of the trees and the season of infection. Following spring infections, when all trees supported active shoot growth, fire blight symptoms progressed more rapidly and to longer distances in trees that exhibited high vigor (i.e., with numerous annual shoots on most terminal branches) than in low-vigor trees (i.e., few or no annual shoots on terminal branches). Irrespective of the vigor of the trees, the progression of fire blight symptoms in perennial branches ceased between mid-May and mid-July, and only a small proportion (0 to 14.2%) of the infections had invaded main limbs or trunks of trees. Progression of fire blight symptoms following autumn infections was related to the preceding summer (August to No-vember) shoot regrowth: in trees in which the shoots did not restore their growth in the summer, the rate of symptom progression in perennial branches was higher in trees with a low vigor than in those with a high vigor, whereas for those with summer regrowth the relationship between rates of symptom expression was reversed. Irrespective of the vigor group and of whether there was summer regrowth, symptoms in perennial branches continued to progress through the winter until the following spring. Most of the autumn infections (50 to 78.5%) that developed in susceptible trees had invaded main limbs or trunks of trees. The results of this study indicate that factors related to host phenology and physiology, rather than factors related to environmental influences (such as temperature), govern the extent, rate, and duration of fire blight progression in perennial pear branches. Furthermore, it turned out that autumn infections play a substantial role in fire blight epidemiology in Israel.

MECHANISMS INVOLVED IN FIRE BLIGHT PROTECTION OF APPLE WITH AN HRPL MUTANT OF ERWINIA AMYLOVORA

2006 ◽  
pp. 481-482
Author(s):  
M. Faize ◽  
M.N. Brisset ◽  
J.P. Paulin ◽  
M. Tharaud ◽  
C. Perino ◽  
...  
Keyword(s):  
Fire Blight ◽  
Erwinia Amylovora ◽  
In Fire

The Role of the Stigma in Fire Blight Infections

1986 ◽  
Vol 76 (5) ◽  
pp. 476 ◽  
Author(s):  
S. V. Thomson
Keyword(s):  
Fire Blight ◽  
In Fire

scholarly journals Examining the Relationship between Fire Interest and Firesetting: Contributions of Previous Experience with Fire and Self and Emotional Regulation

2021 ◽  
Author(s):  
Rosalie Sherrell
Keyword(s):  
Regression Analysis ◽  
Emotional Regulation ◽  
Sensation Seeking ◽  
Economic Cost ◽  
Emotional Dysregulation ◽  
Previous Exposure ◽  
Unique Predictor ◽  
In Fire ◽  
The Relationship

<p>Deliberate firesetting is an international problem with significant personal and economic cost. Interest in fire has previously been identified as a unique predictor of deliberate firesetting, however little is known about how fire interest interacts with other factors to produce firesetting. This research aimed to gain a deeper understanding of the role of fire interest by exploring how this construct interacts with previous exposure to fire and aspects of self and emotional regulation, and how this relates to firesetting behaviour. Two anonymous online studies were conducted among New Zealand adult community samples: Study 1 examined the relationship between fire interest, previous exposure to fire, emotional dysregulation, impulsivity, and sensation seeking (N = 146); Study 2 replicated the first study and explored the relationship between these factors and engagement in deliberate firesetting (N = 149). Results from both studies showed that only previous exposure to fire and sensation seeking were consistently positively correlated with fire interest, however, when other variables were controlled for via multiple regression analysis, the thrill/adventure seeking facet of sensation seeking was the only significant predictor of fire interest. In Study 2, logistic regression showed that only fire interest and impulsivity were significant predictors of deliberate firesetting. Moderation analyses indicated that thrill/adventure seeking moderates the relationship between fire interest and firesetting behaviour, while impulsivity does not. These findings extend previous research and theory by providing an initial understanding of how various factors may influence an individual’s level of fire interest and their engagement in deliberate firesetting. </p>

The temporal evolution of syn-sedimentary normal faults and the possible role of tip retreat

2020 ◽  
Author(s):  
Bailey Lathrop ◽  
Christopher Jackson ◽  
Rebecca Bell ◽  
Atle Rotevatn
Keyword(s):  
Growth Model ◽  
Temporal Evolution ◽  
Fault Model ◽  
Normal Faults ◽  
Constant Length ◽  
Final Length ◽  
Fault Growth ◽  
Stratigraphic Evolution ◽  
The Relationship

&lt;p&gt;We need to understand how normal faults grow in order to better determine the tectono-stratigraphic evolution of rifts, and the distribution and size of potentially hazardous earthquakes. The growth of normal faults is commonly described by two models: 1) the propagating fault model (isolated growth model), and 2) the constant-length model. The propagating fault model envisages a sympathetic increase between fault lengthening (L) and displacement (D), whereas the constant-length model states that faults reach their near-final length before accumulating significant displacement (Walsh et al., 2002). Several relatively recent studies agree that faults generally follow a constant-length model, or a &amp;#8220;hybrid model&amp;#8221; of the two, where most faults reach their near final length within the first 20-30% of their lives, and accrue displacement throughout. Furthermore, in the past 20 years, much research has focused on how faults grow; relatively few studies have questioned what happens to the fault geometry as it becomes inactive, i.e. do faults abruptly die, or do they more gradually become inactive by so-called tip retreat. We here use a 3D seismic reflection dataset from the Exmouth Plateau, offshore Australia to support a hybrid fault growth model for normal faults, and to also determine the relationship between length and displacement as a fault dies. We show that the studied faults grew in three distinct stages: a lengthening stage (&lt;30% of the faults life), a displacement accrual stage (30-75%), and a possible tip retreat stage (75%-end). This work has important implications in our understanding of the temporal evolution of normal faults, both how they grow and how they die.&lt;/p&gt;

scholarly journals HIPM Is a Susceptibility Gene of Malus spp.: Reduced Expression Reduces Susceptibility to Erwinia amylovora

2019 ◽  
Vol 32 (2) ◽  
pp. 167-175 ◽  
Author(s):  
Manuela Campa ◽  
Stefano Piazza ◽  
Laura Righetti ◽  
Chang-Sik Oh ◽  
Lorenza Conterno ◽  
...  
Keyword(s):  
Crop Production ◽  
Fire Blight ◽  
Erwinia Amylovora ◽  
Susceptibility Gene ◽  
Bimolecular Fluorescence Complementation ◽  
Interacting Protein ◽  
Blight Disease ◽  
Oxygen Evolving ◽  
Transgenic Apple

Fire blight, a devastating disease caused by the bacterium Erwinia amylovora, is a major threat to apple crop production. To improve our understanding of the fire blight disease and to identify potential strategies to control the pathogen, we studied the apple protein HIPM (for HrpN-interacting protein from Malus spp.), which has previously been identified as interacting with the E. amylovora effector protein HrpN. Transgenic apple plants were generated with reduced HIPM expression, using an RNA interference construct, and were subsequently analyzed for susceptibility to E. amylovora infection. Lines exhibiting a greater than 50% silencing of HIPM expression showed a significant decrease in susceptibility to E. amylovora infection. Indeed, a correlation between HIPM expression and E. amylovora infection was identified, demonstrating the crucial role of HIPM during fire blight disease progression. Furthermore, an apple oxygen-evolving enhancer-like protein (MdOEE) was identified via a yeast two-hybrid screen to interact with HIPM. This result was confirmed with bimolecular fluorescence complementation assays and leads to new hypotheses concerning the response mechanism of the plant to E. amylovora as well as the mechanism of infection of the bacterium. These results suggest that MdOEE and, particularly, HIPM are promising targets for further investigations toward the genetic improvement of apple.

Colonization of tomatoes by Verticillium dahliae: determinative phase II

1996 ◽  
Vol 74 (8) ◽  
pp. 1279-1288 ◽  
Author(s):  
Julie Gold ◽  
Barbara Lee ◽  
J. Robb
Keyword(s):  
Verticillium Dahliae ◽  
Wilt Disease ◽  
Symptom Expression ◽  
Race 1 ◽  
Race 2 ◽  
The Relationship ◽  
Ve Gene ◽  
Defensive Mechanism ◽  
Colonizing Ability

To investigate the relationship between stem colonizing ability of Verticillium and wilt disease development, the colonization capacities of Verticillium dahliae, race 1 or race 2, were compared in near-isolines of the cultivar Craigella, with (Ve+) and without (Ve−) Ve-gene resistance, and in the cultivar IRAT-L3, which also lacks the Ve-gene. Only the Ve+/V.d.1 interaction was resistant to disease. Lateral and vertical invasiveness of the pathogen were assessed cytologically and fungal biomass was monitored by PCR-based diagnostics. The pathogen was most aggressive in the Ve−/V.d.1 interaction; colonization capacity was reduced in the other five combinations, but most severely, and equivalently, in Ve+/V.d.1, IRAT/V.d.1, and IRAT/V.d.2. Further study of the development and role of the vascular coating response in IRAT-L3 indicated a pattern of expression similar to that observed in other susceptible plants, and it was concluded that the reduced colonization of this cultivar by V. dahliae resulted from another unknown defensive mechanism. Stem colonizing ability that is compatible with resistance in one cultivar and race combination may promote symptom expression and even death in another. Keywords: tomato, Verticillium dahliae, vascular coating, resistance.

Living in a tinderbox: wildfire risk perceptions and mitigating behaviours

2013 ◽  
Vol 22 (6) ◽  
pp. 832 ◽  
Author(s):  
Patricia A. Champ ◽  
Geoffrey H. Donovan ◽  
Christopher M. Barth
Keyword(s):  
Perceived Risk ◽  
Risk Perceptions ◽  
Risk Mitigation ◽  
Front Range ◽  
Wildfire Risk ◽  
Prone Area ◽  
The Usa ◽  
In Fire ◽  
The Relationship

The loss of homes to wildfires is an important issue in the USA and other countries. Yet many homeowners living in fire-prone areas do not undertake mitigating actions, such as clearing vegetation, to decrease the risk of losing their home. To better understand the complexity of wildfire risk-mitigation decisions and the role of perceived risk, we conducted a survey of homeowners in a fire-prone area of the front range of the Rocky Mountains in Colorado. We examine the relationship between perceived wildfire risk ratings and risk-mitigating behaviours in two ways. First, we model wildfire risk-mitigation behaviours as a function of perceived risk. Then, we model wildfire risk-mitigation behaviours and perceived risk simultaneously. The results of the simultaneous model suggest that perceived risk and wildfire risk-mitigating behaviours are jointly determined. By correctly specifying the relationship between risk perceptions and mitigating behaviours, we are better able to understand the relationship between other factors, such as exposure to a wildfire-mitigation program and wildfire risk-mitigating behaviours. We also find that having a wood roof, as well as homeowner age, income and previous experience with living in a fire-prone area, are associated with wildfire risk-mitigating behaviours.

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