Short Communication: Latent Detection of Downy Mildew (Peronospora pisi) in Bioassays against Pisum sativum

Abstract

Downy mildew of peas is caused by the obligate parasite Peronospora pisi, which occurs sporadically throughout temperate pea-growing regions across the world. To screen pea lines against this biotrophic pathogen, a suitable and reproducible in vitro method using living plant material is required. Field screening can be influenced by environmental factors, thus giving variable results. The aim of this study was to develop a method that could reliably be used to screen pea cultivars against P. pisi in a laboratory setting. A range of bioassays were used to test various methods of inoculation, utilizing sporangia and naturally infested soil. Latent infection was achieved by planting seeds in soil collected from a site with a known history of P. pisi infection and directly inoculating young pea plants with sporangia. Out of the 108 plants which survived the experimental period, only two plants expressed visible signs of disease; however, through a two-step nested PCR process we detected latent infection in 24 plants. This research highlights the importance of considering the presence of latent infection when screening pea lines against downy mildew.

Antagonist Temperature Variation Affects the Photosynthetic Parameters and Secondary Metabolites of Ocimum basilicum L. and Salvia officinalis L.

“…Plants are very vulnerable to climate change effects [ 10 , 11 ], such as changes in temperature [ 1 , 2 , 5 ], water status (drought, flooding) [ 12 ], rising atmospheric CO 2 concentration [ 13 , 14 , 15 ], the attacks of herbivores [ 16 , 17 , 18 , 19 ] and pathogens [ 16 , 20 , 21 ]. Among these climate change effects, increased temperatures negatively impact plant development and crop production [ 1 , 11 , 22 ].…”

Exploring the association between latent Plasmopara viticola infection and downy mildew epidemic in commercial vineyards: Application of qPCR assay

“…It is crucial to note that zoospores released through germination of sporangia do not immediately cause visible symptoms. Instead, they establish latent infections within the host tissue and remain dormant until favourable environmental conditions for disease development are met (Marr et al., 2021). Latent infection refers to a phenomenon where the pathogen is present within the host tissue, growing but without immediately eliciting visible disease symptoms.…”

“…The duration of latent infection is defined as the “latency period” and is crucial for disease epidemiology because it determines how many complete infection cycles can occur during an epidemic (Suffert & Thompson, 2018). The length of the latency period varies depending on factors such as specific pathogen–host interactions, infection efficiency, cultivar susceptibility and environmental conditions (Marr et al., 2021; Suffert & Thompson, 2018). Previous research has shown that the latency period of the GDM pathogen after artificial inoculation ranges from 5 to 18 days (Gessler et al., 2011).…”