Histological responses of host and non-host plants to Hyaloperonospora parasitica

Li, Hua; Ge, Xintian; Han, Shiue; Sivasithamparam, Krishnapillai; Barbetti, Martin J.

doi:10.1007/s10658-010-9664-3

Cited by 11 publications

(1 citation statement)

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“…Successful penetration of host tissue is crucial for disease development, and plant pathogens have evolved diverse invasion strategies to ensure this occurs (Mendgen et al, 1996). The infection process of many oilseed brassica pathogens, such as Leptosphaeria maculans (blackleg; Li et al, 2007), Sclerotinia sclerotiorum (sclerotinia stem rot; Garg et al, 2010;Uloth et al, 2015) and Hyaloperonospora parasitica (downy mildew; Li et al, 2011) have been studied extensively. While a recent study on resistance mechanisms in oilseed brassicas, with special emphasis on B. carinata (Gunasinghe et al, 2016b), revealed new information about the infection process of P. capsellae, the study also noted the complex nature of disease progression and the need for further studies to fully define the infection process.…”

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confidence: 99%

Unique infection structures produced by Pseudocercosporella capsellae on oilseed crops Brassica carinata, B. juncea and B. napus in Western Australia

et al. 2016

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White leaf spot disease (Pseudocercosporella capsellae) is widespread across oilseed, vegetable and forage brassicas. Light (LM) and scanning electron (SEM) microscope studies were undertaken to investigate host–pathogen interactions on cotyledons of resistant and susceptible Brassica carinata, B. juncea and B. napus. Under LM, unique brown structures were present, particularly on susceptible genotypes, in two morphologically distinct forms: first, as thread‐like structures within cortical tissue by 24 h post‐inoculation (hpi) and secondly, as brown ropy strand structures either within cortical tissues (internal ropy strands), or extruded out through stomatal pores (ropy strand extrusions). Under LM, these brown structures were most prevalent in highly susceptible B. juncea ‘Vardan’ that had both a high incidence within cortical tissue (70%) and of ropy strand extrusions (73%), as did susceptible B. napus ‘Trilogy’ within cortical tissue (60%). Under SEM, both these genotypes showed thread‐like structures smaller than hyphae forming highly branched networks and ropy strand‐like structures. While there were fewer brown structures in susceptible B. carinata UWA #012 (35%), fine, thread‐like structures forming networks were again prominent (SEM). In contrast, for resistant genotypes, brown structures (LM) were of very low frequency or absent; only 5% in resistant B. juncea ‘Dune’ and none in resistant B. napus ‘Hyola 42’ or highly resistant B. carinata ATC94129P. Under SEM, fine, thread‐like structures were present in the resistant B. juncea ‘Dune’ and B. napus ‘Hyola 42’. Liquid chromatographic analyses of brown structures revealed that both internal ropy strands within cortical tissues and ropy strand extrusions contained the mycotoxin cercosporin.

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