Phytoalexins and Signalling Metabolites Produced in the Wild Crucifer Neslia Paniculata: Camalexins and Arabidopsides

2021 ◽  
Author(s):  
M. Soledade C. Pedras ◽  
Mahla Alavi ◽  
Abbas Abdoli
Keyword(s):  
Plant Species ◽  
Leptosphaeria Maculans ◽  
Blackleg Disease ◽  
In Planta ◽  
First Report ◽  
Signalling Molecules ◽  
The Third ◽  
Hybrid Plants ◽  
In The Wild ◽  
Number Of Plant Species

The metabolites produced in elicited leaves of the wild crucifer <i>Neslia paniculata</i> (L.) Desv. were investigated in abiotically stressed plants. Herein the phytoalexins camalexin, 7-methoxycamalexin and 6,7-dimethoxycamalexin together with the signalling metabolites arabidopsides A and D are reported. This is the first report of occurrence of 7-methoxy and 6,7-dimethoxycamalexins <i>in planta</i> and the third example of synchronized biosynthesis of phytoalexins and galacto-oxylipins. It is suggested that arabidopsides and structurally similar metabolites functioning as signalling molecules are likely to occur in a much larger number of plant species than originally hypothesized. <i>N. paniculata</i> is potentially useful to generate hybrid plants resistant to blackleg disease caused by <i>Leptosphaeria maculans.</i>

scholarly journals Phytoalexins and Signalling Metabolites Produced in the Wild Crucifer Neslia Paniculata: Camalexins and Arabidopsides

2021 ◽  
Author(s):  
M. Soledade C. Pedras ◽  
Mahla Alavi ◽  
Abbas Abdoli
Keyword(s):  
Plant Species ◽  
Leptosphaeria Maculans ◽  
Blackleg Disease ◽  
In Planta ◽  
First Report ◽  
Signalling Molecules ◽  
The Third ◽  
Hybrid Plants ◽  
In The Wild ◽  
Number Of Plant Species

The metabolites produced in elicited leaves of the wild crucifer <i>Neslia paniculata</i> (L.) Desv. were investigated in abiotically stressed plants. Herein the phytoalexins camalexin, 7-methoxycamalexin and 6,7-dimethoxycamalexin together with the signalling metabolites arabidopsides A and D are reported. This is the first report of occurrence of 7-methoxy and 6,7-dimethoxycamalexins <i>in planta</i> and the third example of synchronized biosynthesis of phytoalexins and galacto-oxylipins. It is suggested that arabidopsides and structurally similar metabolites functioning as signalling molecules are likely to occur in a much larger number of plant species than originally hypothesized. <i>N. paniculata</i> is potentially useful to generate hybrid plants resistant to blackleg disease caused by <i>Leptosphaeria maculans.</i>

scholarly journals Phytoalexins and Signalling Metabolites Produced in the Wild Crucifer Neslia Paniculata: Camalexins and Arabidopsides

2021 ◽  
Author(s):  
M. Soledade C. Pedras ◽  
Mahla Alavi ◽  
Abbas Abdoli
Keyword(s):  
Plant Species ◽  
Leptosphaeria Maculans ◽  
Blackleg Disease ◽  
In Planta ◽  
First Report ◽  
Signalling Molecules ◽  
The Third ◽  
Hybrid Plants ◽  
In The Wild ◽  
Number Of Plant Species

The metabolites produced in elicited leaves of the wild crucifer <i>Neslia paniculata</i> (L.) Desv. were investigated in abiotically stressed plants. Herein the phytoalexins camalexin, 7-methoxycamalexin and 6,7-dimethoxycamalexin together with the signalling metabolites arabidopsides A and D are reported. This is the first report of occurrence of 7-methoxy and 6,7-dimethoxycamalexins <i>in planta</i> and the third example of synchronized biosynthesis of phytoalexins and galacto-oxylipins. It is suggested that arabidopsides and structurally similar metabolites functioning as signalling molecules are likely to occur in a much larger number of plant species than originally hypothesized. <i>N. paniculata</i> is potentially useful to generate hybrid plants resistant to blackleg disease caused by <i>Leptosphaeria maculans.</i>

First report of invasive scale insects feeding on the threatened plants Calyptranthes kiaerskovii Krug & Urban and Calyptranthes thomasiana O. Berg in the British Virgin Islands

2019 ◽  
Vol 155 (3) ◽  
pp. 193-199
Author(s):  
C. Malumphy ◽  
S. Bárrios ◽  
M.R. Corcoran ◽  
M.D. Sanchez ◽  
N. Harrigan ◽  
...  
Keyword(s):  
Plant Species ◽  
Virgin Islands ◽  
Scale Insects ◽  
Threatened Plants ◽  
British Virgin Islands ◽  
First Report ◽  
In The Wild ◽  
First Time ◽  
Ceroplastes Floridensis

Invasive scale insects are reported for the first time feeding on the threatened endemic Kiaerskov's lidflower Calyptranthes kiaerskovii and Thomas' lidflower Calyptranthes thomasiana (Myrtaceae) in the British Virgin Islands (BVI). Ceroplastes floridensis Comstock, Ceroplastes rubens Maskell, Paratachardina pseudolobata Kondo & Gullan and an undetermined diaspidid were found on C. kiaerskovii; and C. rubens, Ceroplastes stellifer (Westwood), P. pseudolobata and an undetermined asterolecaniid on C. thomasiana. The significance of these findings and the on-going threats faced by these plant species in the wild are discussed. C. rubens, C. stellifer, P. howertoni Hodges & Hodgson and P. pseudolobata are recorded here for the first time from BVI.

scholarly journals Overexpression of a 3-Ketoacyl-CoA Thiolase in Leptosphaeria maculans Causes Reduced Pathogenicity on Brassica napus

2006 ◽  
Vol 19 (6) ◽  
pp. 588-596 ◽  
Author(s):  
Candace E. Elliott ◽  
Barbara J. Howlett
Keyword(s):  
Brassica Napus ◽  
Leptosphaeria Maculans ◽  
Ectopic Expression ◽  
Random Mutagenesis ◽  
Wild Type ◽  
In Planta ◽  
Functional Protein ◽  
In The Wild ◽  
Dna Insertion

Agrobacterium tumefaciens-mediated random mutagenesis was used to generate insertional mutants of the fungus Leptosphaeria maculans. Of 91 transformants screened, only one (A3) produced lesions of reduced size on cotyledons of canola (Brassica napus). Genes flanking the T-DNA insertion had the best matches to an alcohol dehydrogenase class 4 (ADH4)-like gene (Adh4L) and a 3-ketoacyl-CoA thiolase gene (Thiol) and were expressed in mutant A3 in vitro and in planta at significantly higher levels than in the wild type. This is the first report of a T-DNA insertion in fungi causing increased gene expression. Transformants of the wild-type isolate expressing both Adh4L and Thiol under the control of a heterologous promoter had similar pathogenicity to mutant A3. Ectopic expression of only thiolase resulted in loss of pathogenicity, suggesting that thiolase overexpression was primarily responsible for the reduced pathogenicity of the A3 isolate. The thiolase gene encoded a functional protein, as shown by assays in which a nontoxic substrate (2, 4 dichlorophenoxybutyric acid) was converted to a toxic product. The use of a translational fusion with a reporter gene showed thiolase expressed in organelles that are most likely peroxisomes.

scholarly journals Comparison of non-subjective relative fungal biomass measurements to quantify the Leptosphaeria maculans—Brassica napus interaction

Plant Methods ◽  
2021 ◽  
Vol 17 (1) ◽  
Author(s):  
Wendelin Schnippenkoetter ◽  
Mohammad Hoque ◽  
Rebecca Maher ◽  
Angela Van de Wouw ◽  
Phillip Hands ◽  
...  
Keyword(s):  
Brassica Napus ◽  
Fungal Pathogen ◽  
Fungal Biomass ◽  
Quantitative Resistance ◽  
Leptosphaeria Maculans ◽  
Post Inoculation ◽  
Blackleg Disease ◽  
In Planta ◽  
Visual Assessments ◽  
Host Tissues

Abstract Background Blackleg disease, caused by the fungal pathogen Leptosphaeria maculans, is a serious threat to canola (Brassica napus) production worldwide. Quantitative resistance to this disease is a highly desirable trait but is difficult to precisely phenotype. Visual scores can be subjective and are prone to assessor bias. Methods to assess variation in quantitative resistance more accurately were developed based on quantifying in planta fungal biomass, including the Wheat Germ Agglutinin Chitin Assay (WAC), qPCR and ddPCR assays. Results Disease assays were conducted by inoculating a range of canola cultivars with L. maculans isolates in glasshouse experiments and assessing fungal biomass in cotyledons, petioles and stem tissue harvested at different timepoints post-inoculation. PCR and WAC assay results were well correlated, repeatable across experiments and host tissues, and able to differentiate fungal biomass in different host-isolate treatments. In addition, the ddPCR assay was shown to differentiate between L. maculans isolates. Conclusions The ddPCR assay is more sensitive in detecting pathogens and more adaptable to high-throughput methods by using robotic systems than the WAC assay. Overall, these methods proved accurate and non-subjective, providing alternatives to visual assessments to quantify the L. maculans-B. napus interaction in all plant tissues throughout the progression of the disease in seedlings and mature plants and have potential for fine-scale blackleg resistance phenotyping in canola.

scholarly journals First Report of Blackleg Disease Caused by Leptosphaeria maculans on Canola in Brazil

Plant Disease ◽  
2003 ◽  
Vol 87 (3) ◽  
pp. 314-314 ◽  
Author(s):  
W. G. D. Fernando ◽  
P. S. Parks ◽  
G. Tomm ◽  
L. V. Viau ◽  
C. Jurke
Keyword(s):  
United States ◽  
Brassica Napus ◽  
Rating Scale ◽  
Leptosphaeria Maculans ◽  
Rio Grande ◽  
The United States ◽  
Rio Grande Do Sul ◽  
Blackleg Disease ◽  
First Report ◽  
Testing Procedures

Canola (Brassica napus L.) is a relatively new crop in Brazil, having been grown there for approximately 8 years. In 2000, leaf lesions and stem cankers were observed in cvs. Hyola 420 and Hyola 401 in farmers' fields in the state of Rio Grande do Sul. Cankered stems were received at the University of Manitoba, Canada, from Rio Grande do Sul for disease identification. Small pieces of the stem were cut from the cankered area, and standard protocol was followed to surface sterilize the stem pieces. Stem pieces were plated on V8 agar medium and incubated under light for 12 days. Typical fungal colonies with concentric rings containing pycnidia formed on the V8 agar. The colony characteristics were typical of the blackleg pathogen, Leptosphaeria maculans (Desmaz.) Ces. & De Not. (anamorph = Phoma lingam) (Tode:Fr.) Desmaz.). Blackleg is an economically important and serious disease in many parts of the world including Australia, Canada, the United States, and Europe. L. maculans strains can be characterized in four pathogenicity groups (PG1 through PG4) based on differential testing procedures giving interaction phenotype (IP) reactions (2). Two weeks after plating on V8 media, plates were flooded with sterile distilled water, and pycnidiospores were harvested. Flats of multipots filled with Metro Mix were seeded with three cultivars (Westar, Glacier, and Quinta). One-week-old cotyledons from the three cultivars were inoculated with pycnidiospore suspensions (2 × 107 pycnidiospores per ml) of seven Brazilian isolates, numbered 7, 8, 9, 11, 15, 16, and 18, respectively. Each cotyledon leaf, punctured in the center with a needle, was inoculated with a 10-μl droplet of the inoculum. Disease evaluations were made 11 days after inoculation using a 0 to 9 rating scale (1). This screening was repeated three times from February 2001 to October 2001. After the second repeat, the isolates from Rio Grande do Sul were passed through the highly susceptible canola cv. Westar. Results from all four trials were consistent, and yielded one PG1 isolate (No. 7) and six PG3 isolates. PG1 is classified as a nonaggressive strain, whereas PG3 isolates are classified as aggressive. PG3 isolates would have an IP reaction of 7 to 9, 7 to 9, and 3 to 6 on cvs. Westar, Glacier, and Quinta, respectively. PG2 is the most commonly found aggressive strain in the Canadian prairies. PG3 is predominantly found in Australia, the United Kingdom, and the United States. To our knowledge, this is the first report of blackleg disease caused by L. maculans on canola in Brazil. Differential testing fulfilled Koch's postulates and determined the PG groups found in Brazil (PG1 and PG3). References: (1) P. A. Delwiche. Genetic aspects of blackleg (Leptosphaeria maculans) resistance in rapeseed (Brassica napus) Ph.D. thesis. University of Wisconsin-Madison, 1980. (2) A. Mengistu et al. Plant Dis. 75:1279, 1991.

scholarly journals Habitat preferences of the Critically Endangered greater Bermuda land snail Poecilozonites bermudensis in the wild

Oryx ◽  
2021 ◽  
pp. 1-4
Author(s):  
Alison Copeland ◽  
Thomas Hesselberg
Keyword(s):  
Species Diversity ◽  
Plant Species ◽  
Habitat Preferences ◽  
Land Snail ◽  
Critically Endangered ◽  
Casuarina Equisetifolia ◽  
Invasive Tree ◽  
In The Wild ◽  
A Site ◽  
Number Of Plant Species

Abstract The endemic, Critically Endangered greater Bermuda land snail Poecilozonites bermudensis is known from only two relict subpopulations. Little is known of its habitat preferences in the wild. Observations of released zoo-reared P. bermudensis suggested an affinity for limestone, which we investigated on Port's Island. Previous qualitative observations on Port's Island suggested an aversion to the litter of the invasive tree Casuarina equisetifolia, which we examined. Additionally, we hypothesized that snail abundance would increase with elevation, distance from the sea, and with increased plant species diversity. During 2 May–14 June 2018, we found 558 live P. bermudensis at 70 sites across Port's Island. We found no correlation between the number of live snails at a site and either the number of plant species, elevation or distance from the shoreline, but snails were significantly less abundant at sites dominated by C. equisetifolia. Significantly more snails were found around limestone features, indicating future reintroductions and searches for any undiscovered subpopulations should focus on limestone features where C. equisetifolia is absent.

scholarly journals Melissopalynology of Honey from Sudan: Implication for the Honey Identity and Misdesignation

2020 ◽  
Author(s):  
Mohammed El-Nebir ◽  
Mogbel El-Niweiri ◽  
Seif Eldin Mohammed
Keyword(s):  
Plant Species ◽  
Honey Bees ◽  
Guizotia Abyssinica ◽  
The Third ◽  
Medicinal Value ◽  
The World ◽  
Number Of Plant Species

Due to the great nutritional and medicinal value of honey, there has been growing consumer&rsquo;s preference towards honey of a known identity. However, honey now is the third food in the world subjected to adulteration. Therefore, the current study was focused on judging the identity of Sudanese honeys and checking whether there is any misdesignation from originality. Melissopalynology was used as a tool for this purpose. A number of 60 honey samples were purchased from honey sellers. Results indicated that honey bees foraged on a bio-diversified number of plant species constituted of 11 major families [Fabaceae (43.3%), being the predominant family] and 8 minor families. Respectively, 18.3% &amp;amp; 2% of the honey samples were found to be misdesignated by the honey sellers from their botanical and geographical identities. Some samples were predicted by melissopalynology to be originated from Ethiopia by the presence of marker pollens such as Kniphofia foliosa, Guizotia abyssinica, and Acacia abyssinica an indigenous Ethiopian flora. Thus these findings proved that melissopalynology is an effective tool in judging the identity of honey and pro of being inexpensive.

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