A MADS‐box transcription factor regulates a central step in sporulation of the oomycete Phytophthora infestans

Abstract

MADS-box transcription factors play significant roles in eukaryotes, but have not yet been characterized in oomycetes. Here, we describe a MADS-box protein from Phytophthora infestans, which causes late blight of potato. P. infestans and most other oomycetes express a single MADS-box gene. PiMADS is not transcribed during vegetative growth, but is induced early during asexual sporulation. Its mRNA levels oscillate in response to light, which suppresses sporulation. The protein was not detected in nonsporulating mycelia, but was found in sporulating mycelia and spores. Both mRNA and protein levels decline upon spore germination. A similar expression pattern as well as nuclear localization was observed when the protein was expressed with a fluorescent tag from the native promoter. Gene silencing triggered by a construct expressing 478 nt of MADS sequences indicated that PiMADS is required for sporulation but not hyphal growth or plant colonization. A comparison of wild type to a silenced strain by RNA-seq indicated that PiMADS regulates about 3000 sporulation-associated genes, and acts before other genes previously shown to regulate sporulation. Analysis of the silenced strain also indicated that the native gene was not transcribed while the transgene was still expressed, which contradicts current models for homology-dependent silencing in oomycetes.

Spore Germination of the Obligate Biotroph Spongospora subterranea: Transcriptome Analysis Reveals Germination Associated Genes

“…The MADS-box family proteins are conserved in nearly all eukaryotes and play important roles in signal transduction, responses to environmental stresses and developmental control in plants, fungi and animals. Leesutthiphonchai and Judelson (2018) showed that a MADS−box transcription factor regulates a central step in sporulation of the oomycete Phytophthora infestans (Montagne) de Bary by regulating about 3000 sporulation−associated genes. Their results demonstrated that both mRNA and protein levels of MADS−box transcription factor decline upon P. infestans spore germination.…”

A Cas12a‐based gene editing system for Phytophthora infestans reveals monoallelic expression of an elicitor

“…Such events would typically not be evident in a consensus genome assembly. While the frequencies of interallelic structural and transcriptional polymorphisms in Phytophthora are not well-characterized, there have been reports of hemizygous regions in several species (Dobrowolski et al, 2002;Jiang et al, 2006;Lamour et al, 2012;Martin et al, 2013;Randall et al, 2003).…”

Niche-specific metabolic adaptation in biotrophic and necrotrophic oomycetes is manifested in differential use of nutrients, variation in gene content, and enzyme evolution

“…Polyclonal antibodies against NR were obtained from Agrisera (catalog number AS08 310). Blotting was performed using HRP-labeled anti-rabbit IgG as described [88]. As a positive control, the Ph .…”