Isolation and partial purification of phytotoxins from liquid cultures of <i>Leucostoma cincta</i> and <i>Leucostoma persoonii</i>

Svircev, A. M.; Biggs, Alan R.; Miles, N. W.

doi:10.1139/b91-251

Cited by 7 publications

(2 citation statements)

References 6 publications

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“…Among the 47 secondary metabolism gene clusters, 40% are subjected to gene/transposon insertions or losses in at least one genome. Previous reports showed that phytotoxic small polypeptides secreted by the closely related peach canker pathogens Leucostoma persoonii and Leucostoma cincta can only induce stem necrosis on host plants (Svircev et al, 1991). Some of the Valsa spp.…”

Section: Discussionmentioning

confidence: 99%

Genome sequence of Valsa canker pathogens uncovers a potential adaptation of colonization of woody bark

et al. 2015

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SummaryCanker caused by ascomycetous Valsa species are among the most destructive diseases of woody plants worldwide. These pathogens are distinct from other pathogens because they only effectively attack tree bark in the field. To unravel the potential adaptation mechanism of bark colonization, we examined the genomes of Valsa mali and Valsa pyri that preferentially infect apple and pear, respectively.We reported the 44.7 and 35.7 Mb genomes of V. mali and V. pyri, respectively. We also identified the potential genomic determinants of wood colonization by comparing them with related cereal pathogens.Both genomes encode a plethora of pathogenicity-related genes involved in plant cell wall degradation and secondary metabolite biosynthesis. In order to adapt to the nutrient limitation and low pH environment in bark, they seem to employ membrane transporters associated with nitrogen uptake and secrete proteases predominantly with acidic pH optima. Remarkably, both Valsa genomes are especially suited for pectin decomposition, but are limited in lignocellulose and cutin degradation. Besides many similarities, the two genomes show distinct variations in many secondary metabolism gene clusters.Our results show a potential adaptation of Valsa canker pathogens to colonize woody bark. Secondary metabolism gene clusters are probably responsible for this host specificity.

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Section: Discussionmentioning

confidence: 99%

Genome sequence of Valsa canker pathogens uncovers a potential adaptation of colonization of woody bark

et al. 2015

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“…Deletion of six pectinase genes significantly reduced virulence of V. mali ( Yin et al, 2015 ). Phytotoxic small polypeptides secreted by the closely related peach canker pathogens Leucostoma persoonii and L. cincta can only induce stem necrosis on host plants, reflecting a host specific characteristic ( Svircev et al, 1991 ). In addition, V. mali also possesses homologs of necrosis-inducing factors including NPP1, Ecp2, and Epl ( Yin et al, 2015 ).…”

Section: Discussionmentioning

confidence: 99%

Candidate effector proteins of the necrotrophic apple canker pathogen Valsa mali can suppress BAX-induced PCD

Yin

Fan

et al. 2015

Front. Plant Sci.

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Canker caused by the Ascomycete Valsa mali is the most destructive disease of apple in Eastern Asia, resulting in yield losses of up to 100%. This necrotrophic fungus induces severe necrosis on apple, eventually leading to the death of the whole tree. Identification of necrosis inducing factors may help to unravel the molecular bases for colonization of apple trees by V. mali. As a first step toward this goal, we identified and characterized the V. mali repertoire of candidate effector proteins (CEPs). In total, 193 secreted proteins with no known function were predicted from genomic data, of which 101 were V. mali-specific. Compared to non-CEPs predicted for the V. mali secretome, CEPs have shorter sequence length and a higher content of cysteine residues. Based on transient over-expression in Nicotiana benthamiana performed for 70 randomly selected CEPs, seven V. mali Effector Proteins (VmEPs) were shown to significantly suppress BAX-induced PCD. Furthermore, targeted deletion of VmEP1 resulted in a significant reduction of virulence. These results suggest that V. mali expresses secreted proteins that can suppress PCD usually associated with effector-triggered immunity (ETI). ETI in turn may play an important role in the V. mali–apple interaction. The ability of V. mali to suppress plant ETI sheds a new light onto the interaction of a necrotrophic fungus with its host plant.

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Validation of reference genes for gene expression analysis in Valsa mali var. mali using real-time quantitative PCR

Yin

Huang

et al. 2013

World J Microbiol Biotechnol

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Valsa mali var. mali (Vmm), is the predominant species of apple valsa canker in China. Modern analysis of genes involved in virulence or pathogenicity usually implicate gene expression analysis most often performed using real-time quantitative polymerase chain reaction (RT-qPCR). However, for relative gene expression analysis pertinent reference genes have to be validated before using them as internal reference. This has not been reported for Vmm, so far. Therefore, eight commonly used housekeeping genes (ACT, CYP, EF1-α, G6PDH, GAPDH, L13, TUB, and UBQ) were cloned and evaluated for their expression stability by geNorm and NormFinder. Overall, all of the candidate reference genes were found to be suitable for gene expression analysis. After analysis of 10 samples from different strains and abiotic stress treatments, G6PDH appeared to be the most suitable reference gene, whereas GAPDH was the least suitable. Moreover, taking G6PDH combined with L13 or CYP as reference genes, improved the reliability of RT-qPCR significantly. The influence of the reference system on expression data was demonstrated by analyzing Vmmpg-1 encoding an endo-polygalacturonase gene. Pectinases are considered key pathogenicity factors for this fungus. In order to better understand the role of pectinases in pathogenicity of Vmm, RT-qPCR was used for expression analysis. Our results may provide a guideline for future studies on gene expression of V. mali var. mali by using RT-qPCR.

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Isolation and partial purification of phytotoxins from liquid cultures of Leucostoma cincta and Leucostoma persoonii

Cited by 7 publications

References 6 publications

Genome sequence of Valsa canker pathogens uncovers a potential adaptation of colonization of woody bark

Genome sequence of Valsa canker pathogens uncovers a potential adaptation of colonization of woody bark

Candidate effector proteins of the necrotrophic apple canker pathogen Valsa mali can suppress BAX-induced PCD

Validation of reference genes for gene expression analysis in Valsa mali var. mali using real-time quantitative PCR

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