The Effect of Organic Compounds on the Encystment, Viability and Germination of Zoospores of Phytophthora cinnamomi

Byrt, Pauline N.; Irving, Helen Ruth; Grant, Bruce

doi:10.1099/00221287-128-10-2343

Cited by 11 publications

(7 citation statements)

References 23 publications

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“…By testing serial dilutions of leucine, we found that 5 mM was the minimal concentration affecting zoosporic germination (Table 1). This concentration was similar to the levels of lysine reported by Byrt et al (1982) (reference added to the manuscript) on the study of zoosporic behavior of Phytophthora cinnamomi . In addition, Jones et al (1990) and Deacon and Donaldson (1993) discussed the chemicals and concentrations on the behavior of zoospores for several oomycetes.…”

Section: Discussionsupporting

confidence: 87%

Leucine Regulates Zoosporic Germination and Infection by Phytophthora erythroseptica

Hwang

et al. 2019

Front. Microbiol.

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Pink rot (Phytophthora erythroseptica) of potato is a major concern in many potato production regions. The pathogen produces zoospores that serve as a primary inoculum for infection. To understand how the pink rot incidence is related to pathogen population, qualitative, and quantitative chemical analyses were conducted. It was demonstrated that P. erythroseptica zoospores required a minimal population of 103 zoospores/ml (threshold) for initiating germination and the subsequent infection; the percentage of zoosporic germination was positively correlated with the density of zoospores above the threshold. To elucidate the density-dependent behavior, zoospore exudate (ZE) was extracted from high-density (105/ml) zoospore suspension. Zoosporic inocula of P. erythroseptica at different concentrations were inoculated on potato tubers. Necrotic lesions were caused by inoculum with 100 zoospores per inoculation site; 5 zoospores per site did not cause lesions on the tuber. However, five zoospores did cause lesions when they were placed in ZE, suggesting ZE contained chemical compounds that regulate germination of zoospores. ZE was collected and analyzed using liquid chromatography mass spectroscopy (LC-MS). Results showed that the amino acid leucine was associated with zoosporic germination. Therefore, zoosporic germination and infection of P. erythroseptica were mediated by signaling molecules secreted from zoospores.

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Section: Discussionsupporting

confidence: 87%

Leucine Regulates Zoosporic Germination and Infection by Phytophthora erythroseptica

Hwang

et al. 2019

Front. Microbiol.

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“…Although it had been shown previously (Byrt et al, 1982b) that the effect of pectin was not a result of Ca2 + contamination, the possibility that pectin was acting through Ca2 + remained, since zoospores were released into water containing micromolar concentrations of Ca2 + leached from the mycelium. However, zoospores incubated in the presence of 50 PM-EGTA (pH 6 5 ) , which reduced Ca2 + activity to below M, underwent synchronous encystment and rapid germination ( Fig.…”

Section: Results a N D Discussionmentioning

confidence: 96%

The Effects of Pectin and Plant Root Surface Carbohydrates on Encystment and Development of Phytophthora cinnamomi Zoospores

Irving

Grant

1984

Microbiology

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Citrus pectin induces highly synchronous differentiation in populations of Phytophthora cinnamomizoospores in the absence of a host plant. This action is independent of the presence of Ca2 + in the zoospore suspension medium. Water-soluble, ethanol-insoluble material present on the surface of the plant roots also induces differentiation of P. cinnamomi zoospore populations with the same time course iis pectin. It is proposed that this material provides the natural recognition signal which induces P. cinnamomi zoospores to differentiate, and that pectin is sufficiently similar in structure for it to mimic its action.

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“…Thus, SSRs with leucine CDS may have a vital role in germination, but further in-depth study is required for establishing this link. Basic amino acid lysine and arginine induced encystment in P. cinnamomi ( Byrt et al, 1982 ). This may be the reason why these motifs are conserved across all the Phytophthora species.…”

Section: Resultsmentioning

confidence: 99%

Comparative Genome Analysis Across 128 Phytophthora Isolates Reveal Species-Specific Microsatellite Distribution and Localized Evolution of Compartmentalized Genomes

et al. 2022

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Phytophthora sp. are invasive groups of pathogens belonging to class Oomycetes. In order to contain and control them, a deep knowledge of their biology and infection strategy is imperative. With the availability of large-scale sequencing data, it has been possible to look directly into their genetic material and understand the strategies adopted by them for becoming successful pathogens. Here, we have studied the genomes of 128 Phytophthora species available publicly with reasonable quality. Our analysis reveals that the simple sequence repeats (SSRs) of all Phytophthora sp. follow distinct isolate specific patterns. We further show that TG/CA dinucleotide repeats are far more abundant in Phytophthora sp. than other classes of repeats. In case of tri- and tetranucleotide SSRs also, TG/CA-containing motifs always dominate over others. The GC content of the SSRs are stable without much variation across the isolates of Phytophthora. Telomeric repeats of Phytophthora follow a pattern of (TTTAGGG)n or (TTAGGGT)n rather than the canonical (TTAGGG)n. RxLR (arginine-any amino acid-leucine-arginine) motifs containing effectors diverge rapidly in Phytophthora and do not show any core common group. The RxLR effectors of some Phytophthora isolates have a tendency to form clusters with RxLRs from other species than within the same species. An analysis of the flanking intergenic distance clearly indicates a two-speed genome organization for all the Phytophthora isolates. Apart from effectors and the transposons, a large number of other virulence genes such as carbohydrate-active enzymes (CAZymes), transcriptional regulators, signal transduction genes, ATP-binding cassette transporters (ABC), and ubiquitins are also present in the repeat-rich compartments. This indicates a rapid co-evolution of this powerful arsenal for successful pathogenicity. Whole genome duplication studies indicate that the pattern followed is more specific to a geographic location. To conclude, the large-scale genomic studies of Phytophthora have thrown light on their adaptive evolution, which is largely guided by the localized host-mediated selection pressure.

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The Effect of Organic Compounds on the Encystment, Viability and Germination of Zoospores of Phytophthora cinnamomi

Cited by 11 publications

References 23 publications

Leucine Regulates Zoosporic Germination and Infection by Phytophthora erythroseptica

Leucine Regulates Zoosporic Germination and Infection by Phytophthora erythroseptica

The Effects of Pectin and Plant Root Surface Carbohydrates on Encystment and Development of Phytophthora cinnamomi Zoospores

Comparative Genome Analysis Across 128 Phytophthora Isolates Reveal Species-Specific Microsatellite Distribution and Localized Evolution of Compartmentalized Genomes

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