scholarly journals Unique Attributes of the Laurel Wilt Fungal Pathogen, Raffaelea lauricola, as Revealed by Metabolic Profiling

Pathogens ◽  
2021 ◽  
Vol 10 (5) ◽  
pp. 528
Author(s):  
Ross Joseph ◽  
Michelle Lasa ◽  
Yonghong Zhou ◽  
Nemat O. Keyhani
Keyword(s):  
Fatty Acids ◽  
Metabolic Profiling ◽  
Fungal Pathogen ◽  
Phenotypic Screening ◽  
Chemical Sensitivity ◽  
Carbon Utilization ◽  
Laurel Wilt ◽  
Raffaelea Lauricola ◽  
Metabolic Capability ◽  
Substrate Usage

Raffaelea lauricola is the causative agent of laurel wilt, a devastating disease of lauraceous trees. R. lauricola is also an obligate nutritional symbiont of several ambrosia beetle species who act as vectors for the pathogen. Here, we sought to establish the baseline “phenome” of R. lauricola with knowledge concerning its metabolic capability, expanding our understanding of how these processes are impacted by environmental and host nutrients. Phenotypic screening using a microarray of over one thousand compounds was used to generate a detailed profile of R. lauricola substrate utilization and chemical sensitivity. These data revealed (i) relatively restricted carbon utilization, (ii) broad sulfur and phosphate utilization, and (iii) pH and osmotic sensitivities that could be rescued by specific compounds. Additional growth profiling on fatty acids revealed toxicity on C10 substrates and lower, with robust growth on C12–C18 fatty acids. Conditions for lipid droplet (LD) visualization and LD dynamics were examined using a series of lipid dyes. These data provide unique insights regarding R. lauricola metabolism and physiology, and identify distinct patterns of substrate usage and sensitivity which likely reflect important aspects of the host-microbe interface and can be exploited for the development of strategies for mitigating the spread of laurel wilt.

scholarly journals Laurel Wilt: Current and Potential Impacts and Possibilities for Prevention and Management

Forests ◽  
2021 ◽  
Vol 12 (2) ◽  
pp. 181
Author(s):  
Rabiu O. Olatinwo ◽  
Stephen W. Fraedrich ◽  
Albert E. Mayfield
Keyword(s):  
United States ◽  
Tree Mortality ◽  
The United States ◽  
Persea Americana ◽  
Laurel Wilt ◽  
Important Species ◽  
Invasive Insects ◽  
Raffaelea Lauricola ◽  
Redbay Ambrosia Beetle ◽  
The Impact

In recent years, outbreaks of nonnative invasive insects and pathogens have caused significant levels of tree mortality and disturbance in various forest ecosystems throughout the United States. Laurel wilt, caused by the pathogen Raffaelea lauricola (T.C. Harr., Fraedrich and Aghayeva) and the primary vector, the redbay ambrosia beetle (Xyleborus glabratus Eichhoff), is a nonnative pest-disease complex first reported in the southeastern United States in 2002. Since then, it has spread across eleven southeastern states to date, killing hundreds of millions of trees in the plant family Lauraceae. Here, we examine the impacts of laurel wilt on selected vulnerable Lauraceae in the United States and discuss management methods for limiting geographic expansion and reducing impact. Although about 13 species belonging to the Lauraceae are indigenous to the United States, the highly susceptible members of the family to laurel wilt are the large tree species including redbay (Persea borbonia (L.) Spreng) and sassafras (Sassafras albidum (Nutt.) Nees), with a significant economic impact on the commercial production of avocado (Persea americana Mill.), an important species native to Central America grown in the United States. Preventing new introductions and mitigating the impact of previously introduced nonnative species are critically important to decelerate losses of forest habitat, genetic diversity, and overall ecosystem value.

High efficiency transformation and mutant screening of the laurel wilt pathogen, Raffaelea lauricola

2020 ◽  
Vol 104 (17) ◽  
pp. 7331-7343
Author(s):  
Yonghong Zhou ◽  
Dingding Lu ◽  
Ross Joseph ◽  
Tian Li ◽  
Nemat O. Keyhani
Keyword(s):  
High Efficiency ◽  
Laurel Wilt ◽  
Mutant Screening ◽  
Raffaelea Lauricola

scholarly journals An Acaromyces Species Associated with Bark Beetles from Southern Pine Has Inhibitory Properties Against Raffaelea lauricola, the Causal Pathogen of Laurel Wilt Disease of Redbay

2019 ◽  
Vol 20 (4) ◽  
pp. 220-228 ◽  
Author(s):  
Rabiu Olatinwo ◽  
Stephen Fraedrich
Keyword(s):  
Secondary Metabolites ◽  
Loblolly Pine ◽  
Spore Germination ◽  
Bark Beetles ◽  
Dna Analysis ◽  
The United States ◽  
Malt Extract ◽  
Laurel Wilt ◽  
Raffaelea Lauricola ◽  
Redbay Ambrosia Beetle

Laurel wilt is a destructive disease of redbay (Persea borbonia) and other species in the laurel family (Lauraceae). It is caused by Raffaelea lauricola, a fungal symbiont of the redbay ambrosia beetle, Xyleborus glabratus (Coleoptera: Curculionidae), cointroduced into the United States around 2002. During assessments of fungi associated with bark beetles from loblolly pine, an unknown fungus was isolated that appeared to have broad-spectrum antifungal activities. In this study, we identified the unknown fungus and determined the inhibitory effect of its secondary metabolites on R. lauricola. DNA analysis identified the fungus as Acaromyces ingoldii (GenBank accession no. EU770231). Secondary metabolites produced by the A. ingoldii completely inhibited R. lauricola mycelial growth on potato dextrose agar (PDA) plates preinoculated with A. ingoldii and reduced R. lauricola growth significantly on malt extract agar plates preinoculated with A. ingoldii. R. lauricola isolates inoculated on PDA plates 7 days after A. ingoldii were completely inhibited with no growth or spore germination. Direct evaluation of A. ingoldii crude extract on R. lauricola spores in a multi-well culture plate assay showed inhibition of spore germination at 10% and higher concentrations. Secondary metabolites from A. ingoldii could be potentially useful in managing the future spread of laurel wilt.

scholarly journals First Report of Laurel Wilt, Caused by Raffaelea lauricola, on Sassafras (Sassafras albidum) in Arkansas

Plant Disease ◽  
2016 ◽  
Vol 100 (11) ◽  
pp. 2331 ◽  
Author(s):  
R. Olatinwo ◽  
C. Barton ◽  
S. W. Fraedrich ◽  
W. Johnson ◽  
J. Hwang
Keyword(s):  
Laurel Wilt ◽  
First Report ◽  
Raffaelea Lauricola ◽  
Sassafras Albidum

Raffaelea lauricola (laurel wilt).

2021 ◽  
Author(s):  
Stephen Fraedrich
Keyword(s):  
Solid Wood ◽  
Persea Americana ◽  
South Florida ◽  
Florida Current ◽  
Natural Ecosystems ◽  
Laurel Wilt ◽  
Southeastern Usa ◽  
Raffaelea Lauricola ◽  
Redbay Ambrosia Beetle ◽  
The Usa

Abstract Laurel wilt is responsible for the death of hundreds of millions of redbay (Persea borbonia sensu lato) trees throughout the southeastern USA, and the disease is also having significant effects on other species such as sassafras (Sassafras albidum) in natural ecosystems and avocado (Persea americana) in commercial production areas of south Florida. Laurel wilt is caused by the pathogen Raffaelea lauricola, a fungal symbiont of the redbay ambrosia beetle, Xyleborus glabratus. Thus far, the disease is confined to members of the Lauraceae that are native to the USA, or native to such places as the Caribbean, Central America and Europe and grown in the USA. The beetle and fungus are native to Asia and were likely introduced with untreated solid wood packing material at Port Wentworth, Georgia in the early 2000s. Since that time laurel wilt has spread rapidly in the coastal plains of the southeastern USA, spreading north into central North Carolina, as far west as Texas, and reaching the southernmost counties of Florida. Current models suggest that X. glabratus can tolerate temperature conditions that occur throughout much of the eastern USA, and so the disease threatens sassafras throughout much of this region. The disease poses a threat to lauraceous species indigenous to other areas of the Americas as well as Europe and Africa.

scholarly journals Genetic Analyses of the Laurel Wilt Pathogen, Raffaelea lauricola, in Asia Provide Clues on the Source of the Clone that is Responsible for the Current USA Epidemic

Forests ◽  
2019 ◽  
Vol 10 (1) ◽  
pp. 37 ◽  
Author(s):  
Tyler J. Dreaden ◽  
Marc A. Hughes ◽  
Randy C. Ploetz ◽  
Adam Black ◽  
Jason A. Smith
Keyword(s):  
Genetic Structure ◽  
Laurel Wilt ◽  
Type Locus ◽  
Xyleborus Glabratus ◽  
Genetic Structure Of Populations ◽  
Raffaelea Lauricola ◽  
Host Trees ◽  
Redbay Ambrosia Beetle ◽  
The Usa ◽  
Simple Sequence

Laurel wilt is caused by the fungus Raffaelea lauricola T.C. Harr., Fraedrich and Aghayeva, a nutritional symbiont of its vector the redbay ambrosia beetle, Xyleborus glabratus Eichhoff. Both are native to Asia but appeared in Georgia in the early 2000s. Laurel wilt has since spread to much of the southeastern United States killing >300 million host trees in the Lauraceae plant family. The aims of this research were to elucidate the genetic structure of populations of R. lauricola, to examine its reproductive strategy, and determine how often the pathogen had been introduced to the USA. A panel of 12 simple sequence repeat (SSR) markers identified 15 multilocus genotypes (MLGs) in a collection of 59 isolates from the USA (34 isolates), Myanmar (18), Taiwan (6) and Japan (1). Limited diversity in the USA isolates and the presence of one MAT idiotype (mating type locus) indicated that R. lauricola was probably introduced into the country a single time. MLG diversity was far greater in Asia than the USA. Only three closely related MLGs were detected in the USA, the most prevalent of which (30 of 34 isolates) was also found in Taiwan. Although more work is needed, the present results suggest that a Taiwanese origin is possible for the population of R. lauricola in the USA. Isolates of R. lauricola from Myanmar were distinct from those from Japan, Taiwan and the USA. Although both MAT idiotypes were present in Myanmar and Taiwan, only the population from Taiwan had the genetic structure of a sexually reproducing population.

scholarly journals Sap flow, xylem anatomy and photosynthetic variables of three Persea species in response to laurel wilt

2020 ◽  
Author(s):  
Raiza Castillo-Argaez ◽  
Aime Vazquez ◽  
Joshua L Konkol ◽  
Ana I Vargas ◽  
Randy C Ploetz ◽  
...  
Keyword(s):  
Tree Species ◽  
Sap Flow ◽  
Xylem Sap ◽  
Forest Tree ◽  
Persea Americana ◽  
Xylem Vessel ◽  
Xylem Anatomy ◽  
Laurel Wilt ◽  
Raffaelea Lauricola ◽  
Leaf Chlorophyll

Abstract Laurel wilt, a lethal vascular wilt disease caused by the fungus Raffaelea lauricola, affects several tree species in the Lauraceae, including three Persea species. The susceptibility to laurel wilt of two forest tree species native to the southern United States, Persea borbonia and Persea palustris, and avocado, Persea americana cv Waldin, was examined and related to tree physiology and xylem anatomy. Net CO2 assimilation (A), stomatal conductance (gs), leaf chlorophyll index (LCI), leaf chlorophyll fluorescence (Fv/Fm), xylem sap flow, theoretical stem hydraulic conductivity (Kh) and xylem vessel anatomy were assessed in trees of each species that were inoculated with R. lauricola and in control trees. Laurel wilt caused a reduction in A, gs, LCI, Fv/Fm, and blockage of xylem vessels by tyloses formation that negatively impacted Kh, and sap flow in all Persea species. However, disease susceptibility as indicated by canopy wilting and sapwood discoloration was less pronounced in P. americana cv Waldin than in the two forest species. Xylem vessel diameter was significantly smaller in P. borbonia and P. palustris than in P. americana cv Waldin. Differences in laurel wilt susceptibility among species appears to be influenced by physiological and anatomical tree responses.

Genomic comparisons of the laurel wilt pathogen, Raffaelea lauricola, and related tree pathogens highlight an arsenal of pathogenicity related genes

2019 ◽  
Vol 125 ◽  
pp. 84-92 ◽  
Author(s):  
Jorge R. Ibarra Caballero ◽  
Jongbum Jeon ◽  
Yong-Hwan Lee ◽  
Stephen Fraedrich ◽  
Ned B. Klopfenstein ◽  
...  
Keyword(s):  
Laurel Wilt ◽  
Raffaelea Lauricola

scholarly journals Evaluation of Visible-Near Infrared Reflectance Spectra of Avocado Leaves as a Non-destructive Sensing Tool for Detection of Laurel Wilt

Plant Disease ◽  
2012 ◽  
Vol 96 (11) ◽  
pp. 1683-1689 ◽  
Author(s):  
Sindhuja Sankaran ◽  
Reza Ehsani ◽  
Sharon A. Inch ◽  
Randy C. Ploetz
Keyword(s):  
Discriminant Analysis ◽  
Vegetation Index ◽  
Near Infrared ◽  
Principal Component ◽  
Persea Americana ◽  
Near Infrared Reflectance ◽  
Laurel Wilt ◽  
Linear Discriminant ◽  
Raffaelea Lauricola ◽  
Non Destructive

Laurel wilt, caused by the fungus Raffaelea lauricola, affects the growth, development, and productivity of avocado, Persea americana. This study evaluated the potential of visible-near infrared spectroscopy for non-destructive sensing of this disease. The symptoms of laurel wilt are visually similar to those caused by freeze damage (leaf necrosis). In this work, we performed classification studies with visible-near infrared spectra of asymptomatic and symptomatic leaves from infected plants, as well as leaves from freeze-damaged and healthy plants, both of which were non-infected. The principal component scores computed from principal component analysis were used as input features in four classifiers: linear discriminant analysis, quadratic discriminant analysis (QDA), Naïve-Bayes classifier, and bagged decision trees (BDT). Among the classifiers, QDA and BDT resulted in classification accuracies of higher than 94% when classifying asymptomatic leaves from infected plants. All of the classifiers were able to discriminate symptomatic-infected leaves from freeze-damaged leaves. However, the false negatives mainly resulted from asymptomatic-infected leaves being classified as healthy. Analyses of average vegetation indices of freeze-damaged, healthy (non-infected), asymptomatic-infected, and symptomatic-infected leaves indicated that the normalized difference vegetation index and the simple ratio index were statistically different.

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