scholarly journals The role of reactive oxygen in the development of Ramularia leaf spot disease in barley seedlings

2017 ◽  
Vol 121 (3) ◽  
pp. 415-430 ◽  
Author(s):  
Graham R D McGrann ◽  
James K M Brown
Keyword(s):  
Leaf Spot ◽  
Reactive Oxygen ◽  
Leaf Spot Disease ◽  
Spot Disease ◽  
Ramularia Leaf Spot

scholarly journals Cercosporin From Pseudocercosporella capsellae and its Critical Role in White Leaf Spot Development

Plant Disease ◽  
2016 ◽  
Vol 100 (8) ◽  
pp. 1521-1531 ◽  
Author(s):  
Niroshini Gunasinghe ◽  
Ming Pei You ◽  
Gregory R. Cawthray ◽  
Martin J. Barbetti
Keyword(s):  
Host Species ◽  
Leaf Spot ◽  
Critical Role ◽  
Chemical Extraction ◽  
Leaf Spot Disease ◽  
Raphanus Raphanistrum ◽  
Spot Disease ◽  
White Leaf ◽  
Pink Pigment

Pseudocercosporella capsellae, the causative agent of white leaf spot disease in Brassicaceae, can produce a purple-pink pigment on artificial media resembling, but not previously confirmed as, the toxin cercosporin. Chemical extraction with ethyl acetate from growing hyphae followed by quantitative (thin-layer chromatography [TLC] and high-performance liquid chromatography [HPLC]) and qualitative methods showed an identical absorption spectrum, with similar retardation factor (Rf) values on TLC papers and an identical peak with the same retention time in HPLC as for a standard for cercosporin. We believe this is the first report to confirm that the purple-pink pigment produced by P. capsellae is cercosporin. Confocal microscopy detected green autofluorescence of cercosporin-producing hyphae, confirming the presence of cercosporin inside hyphae. The highly virulent UWA Wlra-7 isolate of P. capsellae produced the greatest quantity of cercosporin (10.69 mg g−1). The phytotoxicity and role of cercosporin in disease initiation across each of three Brassicaceae host species (Brassica juncea, B. napus, and Raphanus raphanistrum) was also studied. Culture filtrates containing cercosporin were phytotoxic to all three host plant species, producing large, white lesions on highly sensitive B. juncea, only water-soaked areas on least sensitive R. raphanistrum, and intermediate lesions on B. napus. It is noteworthy that sensitivity to cercosporin of these three host species was analogous to their susceptibility to the pathogen, viz., B. juncea the most susceptible, R. raphanistrum the least susceptible, and B. napus intermediate. The presence of cercosporin in the inoculum significantly increased disease severity on the highly cercosporin-sensitive B. juncea. We believe that this is the first study to demonstrate that P. capsellae produces cercosporin in liquid culture rather than agar media. Finally, this study highlights an important role of cercosporin as a pathogenicity factor in white leaf spot disease on Brassicaceae as evidenced by the ability of the cercosporin-rich culture filtrate to reproduce white leaf spot lesions on host plants and by the enhanced virulence of P. capsellae in the presence of cercosporin.

scholarly journals Dissection of Ramularia Leaf Spot Disease by Integrated Analysis of Barley and Ramularia collo-cygni Transcriptome Responses

2019 ◽  
Vol 32 (2) ◽  
pp. 176-193 ◽  
Author(s):  
Elisabet Sjokvist ◽  
Rene Lemcke ◽  
Manoj Kamble ◽  
Frances Turner ◽  
Mark Blaxter ◽  
...  
Keyword(s):  
Leaf Spot ◽  
Expression Patterns ◽  
Asymptomatic Infection ◽  
Integrated Analysis ◽  
Leaf Spot Disease ◽  
In Planta ◽  
Transcriptional Responses ◽  
Spot Disease ◽  
Ramularia Leaf Spot ◽  
Infection Stage

Ramularia leaf spot disease (RLS), caused by the ascomycete fungus Ramularia collo-cygni, has emerged as a major economic disease of barley. No substantial resistance has been identified, so far, among barley genotypes and, based on the epidemiology of the disease, a quantitative genetic determinacy of RLS has been suggested. The relative contributions of barley and R. collo-cygni genetics to disease infection and epidemiology are practically unknown. Here, we present an integrated genome-wide analysis of host and pathogen transcriptome landscapes identified in a sensitive barley cultivar following infection by an aggressive R. collo-cygni isolate. We compared transcriptional responses in the infected and noninfected leaf samples in order to identify which molecular events are associated with RLS symptom development. We found a large proportion of R. collo-cygni genes to be expressed in planta and that many were also closely associated with the infection stage. The transition from surface to apoplastic colonization was associated with downregulation of cell wall–degrading genes and upregulation of nutrient uptake and resistance to oxidative stresses. Interestingly, the production of secondary metabolites was dynamically regulated within the fungus, indicating that R. collo-cygni produces a diverse panel of toxic compounds according to the infection stage. A defense response against R. collo-cygni was identified in barley at the early, asymptomatic infection and colonization stages. We found activation of ethylene signaling, jasmonic acid signaling, and phenylpropanoid and flavonoid pathways to be highly induced, indicative of a classical response to necrotrophic pathogens. Disease development was found to be associated with gene expression patterns similar to those found at the onset of leaf senescence, when nutrients, possibly, are used by the infecting fungus. These analyses, combining both barley and R. collo-cygni transcript profiles, demonstrate the activation of complex transcriptional programs in both organisms.

TWO NEW SEVERE LEAF SPOT DISEASE ON FOREST TREES OF JALGAON (MAHARASTRA) INDIA

2017 ◽  
Vol 23 (2) ◽  
Author(s):  
S. A. FIRDOUSI
Keyword(s):  
Leaf Spot ◽  
Fungal Disease ◽  
Leaf Spot Disease ◽  
Forest Trees ◽  
First Report ◽  
Spot Disease ◽  
Severe Leaf

During the survey of the forest fungal disease, of Jalgaon district, two severe leaf spot diseases on Lannae coromandelica and ( Ougenia dalbergioides (Papilionaceae) were observed in Jalgaon, forest during July to September 2016-17. The casual organism was identified as Stigmina lanneae and Phomopsis sp. respectively1-4,7. These are first report from Jalgaon and Maharashtra state.

Rapid Inoculation Technique and Biological Control of Leaf Spot Disease in Oil Palm

2019 ◽  
Vol 2 (1) ◽  
pp. 1-11 ◽  
Author(s):  
Delia Agustina ◽  
◽  
Cahya Prihatna ◽  
Antonius Suwanto ◽  
◽  
...  
Keyword(s):  
Biological Control ◽  
Oil Palm ◽  
Leaf Spot ◽  
Leaf Spot Disease ◽  
Inoculation Technique ◽  
Spot Disease

scholarly journals Registration of three peanut allotetraploid interspecific hybrids resistant to late leaf spot disease and tomato spotted wilt

2021 ◽  
Author(s):  
Ye Chu ◽  
H. Thomas Stalker ◽  
Kathleen Marasigan ◽  
Chandler M. Levinson ◽  
Dongying Gao ◽  
...  
Keyword(s):  
Leaf Spot ◽  
Interspecific Hybrids ◽  
Leaf Spot Disease ◽  
Late Leaf Spot ◽  
Spot Disease ◽  
Tomato Spotted Wilt
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