Stigmasterol and Cholesterol Regulate the Expression of Elicitin Genes in Phytophthora sojae

Yousef, Lina F.; Yousef, Ahmed F.; Mymryk, Joseph S.; Dick, Warren A.; Dick, Richard P.

doi:10.1007/s10886-009-9653-1

Cited by 15 publications

(7 citation statements)

References 32 publications

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“…Transient assay showed that one of P. capsici elicitin genes ( Pc508761 ) induced plant cell death (Figure 7A). Future studies will involve an exploration of whether these elicitins are required for host infection or sterol acquisition [78].…”

Section: Discussionmentioning

confidence: 99%

RNA-Seq Reveals Infection-Related Gene Expression Changes in Phytophthora capsici

Chen

Xing

et al. 2013

PLoS ONE

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Phytophthora capsici is a soilborne plant pathogen capable of infecting a wide range of plants, including many solanaceous crops. However, genetic resistance and fungicides often fail to manage P. capsici due to limited knowledge on the molecular biology and basis of P. capsici pathogenicity. To begin to rectify this situation, Illumina RNA-Seq was used to perform massively parallel sequencing of three cDNA samples derived from P. capsici mycelia (MY), zoospores (ZO) and germinating cysts with germ tubes (GC). Over 11 million reads were generated for each cDNA library analyzed. After read mapping to the gene models of P. capsici reference genome, 13,901, 14,633 and 14,695 putative genes were identified from the reads of the MY, ZO and GC libraries, respectively. Comparative analysis between two of samples showed major differences between the expressed gene content of MY, ZO and GC stages. A large number of genes associated with specific stages and pathogenicity were identified, including 98 predicted effector genes. The transcriptional levels of 19 effector genes during the developmental and host infection stages of P. capsici were validated by RT-PCR. Ectopic expression in Nicotiana benthamiana showed that P. capsici RXLR and Crinkler effectors can suppress host cell death triggered by diverse elicitors including P. capsici elicitin and NLP effectors. This study provides a first look at the transcriptome and effector arsenal of P. capsici during the important pre-infection stages.

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Section: Discussionmentioning

confidence: 99%

RNA-Seq Reveals Infection-Related Gene Expression Changes in Phytophthora capsici

Chen

Xing

et al. 2013

PLoS ONE

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“…There is the possibility that P. sojae produces and secretes other proteins than just class-I elicitins. However, we previously determined that the most abundant protein in spent filtrates of the organism were class-I elicitins using 2D-PAGE followed by LC-MS analysis (Yousef et al 2009). This was also confirmed in this study by visually inspecting spent filtrates on PAGE (data not shown), in which class-I elicitins were the only proteins detected in spent filtrates after silver staining.…”

Section: Discussionmentioning

confidence: 99%

“…Because of the auxotrophic requirement for sterols combined with the in vitro sterol binding activity of class-I elicitins, it has been hypothesized that elicitins act as shuttles that transport sterols from the environment to the pathogen . Yousef et al (2009) found that nanomolar concentrations of sterols (stigmasterol and cholesterol) caused a down-regulation of class-I elicitin gene expression. This also coincided with a reduction in class-I elicitin protein secretion into the spent broth.…”

Section: Introductionmentioning

confidence: 99%

“…First, it is known that class-I elicitin genes in P. sojae become down-regulated over time when nanomolar concentrations of stigmasterol are present in the growth medium (Yousef et al 2009), which also coincided with reduced detection of elicitins in the spent broth. Second, previous studies have shown that elicitins exhibit sterol carrier activity in vitro (Mikes et al 1998;Vauthrin et al 1999).…”

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confidence: 99%

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Use of a 15N-tracer Method as a Tool to Indicate the Assimilation of Elicitin-Sterol Complexes by Phytophthorasojae

Yousef¹,

Dick²,

Dick³

2011

IJB

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The mechanism of sterol acquisition and transport in oomycetes of the genus Phytophthora is suspected to involve secreted class-I elicitins, but little information is available to confirm this. The objective of this study was to determine if class-I elicitins of Phytophthorasojaepromote assimilation into this organism when a phytosterol is amended into its growth medium using a qualitative 15 N tracer method. Two P. sojae growth experiments were conducted involving 15 N labeled mycelium or 15 N spent broth containing putative P. sojaeelicitins in the absence or presence of a phytosterol (stigmasterol). Mycelium was harvested after 0, 2, 3 or 6 days of growth and analyzed for  N by Elemental Analysis-Isotopic Ratio Mass Spectrometry (EA-IRMS).Results from the two experiments demonstrated that P. sojae assimilated putative elicitins from the spent broth more rapidly when stigmasterol was present in the growth medium. These results provide evidence for the involvement of secreted class-I elicitins in sterol acquisition by P. sojae.

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“…The sterol biosynthesis sub-branch of the MVA pathway has been identified in animals, fungi, and land plants (Figure 1; Desmond and Gribaldo, 2009;Ruiz-Sola et al, 2016). In contrast, oomycete species in the genera Phytophthora and Pythium are sterol auxotrophs that utilize exogenous sterols from the environment or from host plants to support their growth and development (Marshall et al, 2001;Yousef et al, 2009). Genome analyses revealed that most enzymes of the sterol biosynthesis sub-branch are absent in Phytophthora species, which makes them unable to synthesize sterol independently (Tyler et al, 2006;Dahlin et al, 2017).…”

Section: Introductionmentioning

confidence: 99%

The Mevalonate Pathway Is Important for Growth, Spore Production, and the Virulence of Phytophthora sojae

et al. 2021

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The mevalonate (MVA) pathway in eukaryotic organisms produces isoprenoids, sterols, ubiquinone, and dolichols. These molecules are vital for diverse cellular functions, ranging from signaling to membrane integrity, and from post-translational modification to energy homeostasis. However, information on the MVA pathway in Phytophthora species is limited. In this study, we identified the MVA pathway genes and reconstructed the complete pathway in Phytophthora sojae in silico. We characterized the function of the MVA pathway of P. sojae by treatment with enzyme inhibitor lovastatin, deletion of the geranylgeranyl diphosphate synthase gene (PsBTS1), and transcriptome profiling analysis. The MVA pathway is ubiquitously conserved in Phytophthora species. Under lovastatin treatment, mycelial growth, spore production, and virulence of P. sojae were inhibited but the zoospore encystment rate increased. Heterozygous mutants of PsBTS1 showed slow growth, abnormal colony characteristics, and mycelial morphology. Mutants showed decreased numbers of sporangia and oospores as well as reduced virulence. RNA sequencing analysis identified the essential genes in sporangia formation were influenced by the enzyme inhibitor lovastatin. Our findings elucidate the role of the MVA pathway in P. sojae and provide new insights into the molecular mechanisms underlying the development, reproduction, and virulence of P. sojae and possibly other oomycetes. Our results also provide potential chemical targets for management of plant Phytophthora diseases.

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Stigmasterol and Cholesterol Regulate the Expression of Elicitin Genes in Phytophthora sojae

Cited by 15 publications

References 32 publications

RNA-Seq Reveals Infection-Related Gene Expression Changes in Phytophthora capsici

RNA-Seq Reveals Infection-Related Gene Expression Changes in Phytophthora capsici

Use of a 15N-tracer Method as a Tool to Indicate the Assimilation of Elicitin-Sterol Complexes by Phytophthorasojae

The Mevalonate Pathway Is Important for Growth, Spore Production, and the Virulence of Phytophthora sojae

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