Effect of light and dark on the growth and development of downy mildew pathogen Hyaloperonospora arabidopsidis. (27th May 2020)

• Record Type: Journal Article
• Authors: Telli, Osman; Jimenez‐Quiros, Catherine; McDowell, John M.; Tör, Mahmut
• Is Part Of: Plant pathology. Volume 69:Number 7(2020)
• Page Start: 1291
• Page End: 1300
• Publication Date: 2020-05-27
• Subjects: Arabidopsis -- circadian rhythm -- downy mildew -- light regime -- oomycetes; Agricultural pests -- Periodicals; Plant diseases -- Periodicals; 632
• DOI: 10.1111/ppa.13207
• Languages: English
• ISSNs: 0032-0862

Abstract

Abstract: Disease development in plants requires a susceptible host, a virulent pathogen, and a favourable environment. Oomycete pathogens cause many important diseases and have evolved sophisticated molecular mechanisms to manipulate their hosts. Day length has been shown to impact plant–oomycete interactions but a need exists for a tractable reference system to understand the mechanistic interplay between light regulation, oomycete pathogen virulence, and plant host immunity. Here we present data demonstrating that light is a critical factor in the interaction between Arabidopsis thaliana and its naturally occurring downy mildew pathogen Hyaloperonospora arabidopsidis (Hpa). We investigated the role of light on spore germination, mycelium development, sporulation, and oospore formation of Hpa, along with defence responses in the host. We observed abundant Hpa sporulation on compatible Arabidopsis under day lengths ranging from 10 to 14 hr. In contrast, exposure to constant light or constant dark suppressed sporulation. Exposure to constant dark suppressed spore germination, mycelial development, and oospore formation, whereas exposure to constant light stimulated these three stages of development. A biomarker of plant immune system activation was induced under both constant light and constant dark. Altogether, these findings demonstrate that Hpa has the molecular mechanisms to perceive and respond to light and that both the host and pathogen responses are influenced by the light regime. Therefore, this pathosystem can be used for investigations to understand the molecular mechanisms through which oomycete pathogens like Hpa perceive and integrate light signals, and how light influences pathogen virulence and host immunity during their interactions. Abstract : Constant light suppressed sporulation but stimulated spore germination, mycelial development and oospore formation, while constant dark suppressed spore germination, mycelial development, sporulation and oospore formation.