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Life cycle of Sclerotinia sclerotiorum and S. minor on sunflower. Carpogenic germination of sclerotia resulting in head rot of sunflower and mycelial germination of sclerotia resulting in basal stem rot of sunflower.
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This study confirms that Australian isolates of Sclerotinia minor can produce fertile apothecia and further demonstrates that ascospores collected from these apothecia are pathogenic to sunflower (Helianthus annuus). Sunflower is a known host of the related fungus Sclerotinia sclerotiorum and is grown in some regions where S. minor is known to occu...
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Context 1
... (Helianthus annuus) is a common host for both S. sclerotiorum and S. minor (Fig. 1). Soilborne sclerotia of both fungi, seemingly stimulated by root exudates, will undergo myceliogenic germination in the presence of sunflower roots (Burgess and Hepworth 1996;Burgess et al. 1995). Colonisation of lateral roots, tap root and stem base results in basal stem rot and wilt and, if the rot is extensive, death of the plant ...
Context 2
... in the sugary exudates from the extra- floral nectaries found along the leaf margins of some genotypes of sunflower can germinate and colonise the leaf, petiole and, ultimately, the stem to cause stem rot (Sedun and Brown 1986b). Ascospores deposited among the florets during anthesis can lead to colonisation of the capitulum to cause head rot (Fig. 1). Initial infection is followed by a short incubation period before external symptoms become apparent on the dorsal surface of the ...
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The sunflower (Helianthus annuus L.) is one of the most important crops grown for edible oil. Sclerotinia sclerotiorum (Lib.) de Bary is a common and widespread pathogen of sunflower. In the present study the reaction of 35 genotypes, including recombinant inbred lines and their parents, M7 mutant lines developed by gamma irradiation, and some geno...
Citations
... Sclerotium germinates directly (myceliogenic) or indirectly (carpogenic) and signals the inception of a new cycle of disease. Myceliogenic germination (by mycelium), possibly triggered by root exudates, is the primary mode of infection and is important from an epidemiological standpoint [18]. Mycelia from soilborne sclerotia may directly initiate infection on roots and basal stem. ...
... Mycelia from soilborne sclerotia may directly initiate infection on roots and basal stem. Basal stem rot and wilt, and in extreme cases, plant death, are the outcomes of the colonization of lateral roots, tap roots, and stem bases [18]. Ascospores released following carpogenic germination of sclerotia may also induce infection in plants. ...
... In flower plants, ascospores that land in the sugary secretions of the extrafloral nectaries adjacent to the leaf margins germinate and colonize the leaf, leafstalk, and, eventually, the stem, causing stem rot [18]. During blossoming, the deposition of ascospores among the florets can result in the colonization of the capitulum, which causes bud rot ( Figure 1). ...
Sclerotinia sclerotiorum (Lib.) de Bary is a broad host-range fungus that infects an inclusive array of plant species and afflicts significant yield losses globally. Despite being a notorious pathogen, it has an uncomplicated life cycle consisting of either basal infection from myceliogenically germinated sclerotia or aerial infection from ascospores of carpogenically germinated sclerotia. This fungus is unique among necrotrophic pathogens in that it inevitably colonizes aging tissues to initiate an infection, where a saprophytic stage follows the pathogenic phase. The release of cell wall-degrading enzymes, oxalic acid, and effector proteins are considered critical virulence factors necessary for the effective pathogenesis of S. sclerotiorum. Nevertheless, the molecular basis of S. sclerotiorum pathogenesis is still imprecise and remains a topic of continuing research. Previous comprehensive sequencing of the S. sclerotiorum genome has revealed new insights into its genome organization and provided a deeper comprehension of the sophisticated processes involved in its growth, development, and virulence. This review focuses on the genetic and genomic aspects of fungal biology and molecular pathogenicity to summarize current knowledge of the processes utilized by S. sclerotiorum to parasitize its hosts. Understanding the molecular mechanisms regulating the infection process of S. sclerotiorum will contribute to devising strategies for preventing infections caused by this destructive pathogen.
... Depending on environmental conditions, sclerotia of S. sclerotiorum germinate myceliogenically to infect basal stems or carpogenically to infect upper plant parts. Sclerotia of S. minor primarily tend to germinate myceliogenically; carpogenic germination is of little importance with regard to development of the disease under field conditions (Abawi and Grogan 1979;Bolton et al. 2006;Ekins et al. 2002;Saharan and Mehta 2008;Willets and Wong 1980). ...
Basal stem rot (BSR), caused by Sclerotinia sclerotiorum and Sclerotinia minor, is one of the most devastating diseases of sunflower worldwide. The use of resistant cultivars is the most economical strategy to manage BSR. However, development of cultivars with effective resistance requires adequate information on the interactions of host genotypes with pathogen isolates. To this aim, the present study was conducted to assess the reactions of 100 oilseed sunflower genotypes of diverse origin to three isolates of each of S. sclerotiorum and S. minor at the seedling stage in growth room conditions. Sunflower genotypes exhibited isolate-specific resistance (differential interactions) to both Sclerotinia species. Among interactions (n = 600), 24 isolate-specific resistances were found to S. sclerotiorum and six to S. minor in 24 genotypes. None of the genotypes was resistant to all fungal isolates. Among the resistant genotypes, “H543R/H543R” and “110” were resistant to two isolates of S. sclerotiorum, whereas others were resistant to one isolate of each of the pathogens. Furthermore, 21 genotypes were specifically resistant to only isolates of S. sclerotiorum or only isolates of S. minor, while, “8A*/LC1064C,” “H156A/H543R,” and “110” showed resistance to one or two isolates of both fungal species. Comparison of mean disease severity scores revealed that sunflower genotype “110” had the greatest general resistance to S. sclerotiorum and genotype “ENSAT 699” to S. minor. Cluster analysis effectively identified the existence of genetic variability among sunflower genotypes and classified them into three or four separate classes based on disease severity scores after infection by S. sclerotiorum and S. minor, respectively. The expression level of pathogenesis-related 5 (PR5) protein was investigated in a resistant (8A*/LC1064C) and a susceptible genotype (SDR19) inoculated with S. sclerotiorum isolates. Mean comparison revealed that the expression of PR5 in 8A*/LC1064C was fivefold higher than SDR19 at 3 h after inoculation indicating the possible involvement of this protein in resistance. The resistance sources identified in the present study have the potential for use in breeding programs to develop sunflower hybrids with BSR resistance.
... After initiation, the interwoven hyphae increase in size and finally it becomes mature by exterior delimitation, internal consolidation and melanization, which are later related with drop discharge. Sclerotia of S. sclerotiorum has the ability to develop in one or more ways namely carpogenic and myceliogenic, although carpogenic germination mostly found in S. sclerotiorum (Ekins et al., 2002;Hao et al., 2003;Clarkson et al., 2004). In myceliogenic germination, sclerotia in occurrence of exogenous nutrients can germinate and generate hyphae that directly infects living tissues of the host plant (Saharan and Mehta, 2008). ...
... After initiation, the interwoven hyphae increase in size and finally it becomes mature by exterior delimitation, internal consolidation and melanization, which are later related with drop discharge. Sclerotia of S. sclerotiorum has the ability to develop in one or more ways namely carpogenic and myceliogenic, although carpogenic germination mostly found in S. sclerotiorum (Ekins et al., 2002;Hao et al., 2003;Clarkson et al., 2004). In myceliogenic germination, sclerotia in occurrence of exogenous nutrients can germinate and generate hyphae that directly infects living tissues of the host plant (Saharan and Mehta, 2008). ...
Upsurge of pollution in agricultural realm is a major concern
globally. Heavy metals, xenobiotic substances, pesticides, agricultural
chemicals desist decaying and turn toxic, affecting plants, humans and
animals after surpassing specific threshold. Environmental pollution
reduces biological quality and properties of soil allowing more
application of fertilizers and pesticides at high rate. Anthropogenic
activities including agricultural and commercial disposal, smelting,
mining, waste water discharge and detritus incineration contributes in
pollution of agrarian regions. Phytoremediation, utilizing
hyperaccumulator plants viz Brassica species, mainly Indian mustard (Brassica juncea) for removal of contaminants from soil is intended as
feasible approach for such catastrophe. Phytoremediation is economically
efficient, restorative, eco-friendly and innocuous technology, barring
challenges in speedy recovery of soil due to slow plant growth, suitable
for particular pollutants only and compartmentalization in plant parts.
Members of Brassicaceae family possess a vital role in phytoremediation
technique. Many of crucifer species are known as hyperaccumulators,
with inherit genes for resistance towards toxicity of contaminants.
Administration of organic matter, chelating agents, approving appropriate
cropping systems, adequate fertilizers, soil amendments and intercrops
may boost phytoremediation capacity of Brassica juncea. Cultivating
Brassica juncea under mentioned conditions will augment assimilating
ability of toxicants in polluted soils.
... After initiation, the interwoven hyphae increase in size and finally it becomes mature by exterior delimitation, internal consolidation and melanization, which are later related with drop discharge. Sclerotia of S. sclerotiorum has the ability to develop in one or more ways namely carpogenic and myceliogenic, although carpogenic germination mostly found in S. sclerotiorum (Ekins et al., 2002;Hao et al., 2003;Clarkson et al., 2004). In myceliogenic germination, sclerotia in occurrence of exogenous nutrients can germinate and generate hyphae that directly infects living tissues of the host plant (Saharan and Mehta, 2008). ...
Brassica juncea, one of the large scales and well-known oilseed crops out of six cultivated Brassicaceae species. This species was evolved by Brassica nigra and Brassica rapa hybrid and claimed to have originated 10,000 years ago. It is a natural species of amphidiploids (AABB genome, 2n=36). That very same species is cultivated primarily in Bangladesh, Central Africa, China, India, Japan, Nepal, and Pakistan as well as in southern Russia north of the Caspian Sea, except in northern and Polar Regions with an average annual temperature below 6°C. Brassica juncea production globally from Boreal Wet to Tropical Thorn across moist forest life zones and can withstand 500 to 4200 mm annual precipitation, 6 to 27°C annual temperature, and pH of 4.3 to 8.3. The seeds, oil, and leaves are a source of numerous potentially bioactive phytochemicals. Albeit this species has various applications in the production of biodiesel and insecticidal, fungicidal, nematicidal, and medicinal activities as well as for its bioremediation. Glucosinolate is responsible for insecticidal activity. It is used to treat arthritis, foot ache, lumbago, and rheumatism, it acts as an anodyne, aperitif, emetic, rubefacient, and stimulant. Seeds are used in China for the treatment of tumors and leaves are eaten in soups to treat bladder disorders, inflammation, or hemorrhage. Abscesses, colds, lumbago, rheumatism, and gastrointestinal disorder are treated in Korea, while in Java it is considered as an antisyphilitic emmenagogue. Skin conditions can be treated with Mustard oil. Studies evaluated the healing and pharmacological properties of B. juncea.
... After initiation, the interwoven hyphae increase in size and finally it becomes mature by exterior delimitation, internal consolidation and melanization, which are later related with drop discharge. Sclerotia of S. sclerotiorum has the ability to develop in one or more ways namely carpogenic and myceliogenic, although carpogenic germination mostly found in S. sclerotiorum (Ekins et al., 2002;Hao et al., 2003;Clarkson et al., 2004). In myceliogenic germination, sclerotia in occurrence of exogenous nutrients can germinate and generate hyphae that directly infects living tissues of the host plant (Saharan and Mehta, 2008). ...
Brassica juncea (Mustard) is an annual herb of the Cruciferae family, daily ingestion of this plant provides a good source of potentially bioactive compounds that affect physiological or cellular activities in humans or animals consuming these compounds. These include phytosterols, glycosinolates, flavonoids, phenolic compounds, essential oils, fixed oils, proteins, and carbohydrates. All these bioactive compounds contribute towards antioxidant, anti-inflammatory, anti-tumor, anti-allergic, and antimicrobial activities. It is a healthy, effective, and affordable way to avoid many of today’s most prevalent and lethal cancers, almost directly linked to poor diet and related causes to integrate these potent plant-based compounds into a regular diet. These edible crucifers’ bioactive compounds foster beneficial effects considered to be effective substitutes for some so-called “healthy” Brassica vegetables. Such beneficial effects make them good candidates for the production of novel functional foods with possible antioxidant and preservative properties. The variety of novel health consequences of bioactive compounds warrant more exploration of Brassica as a possible source of pharmacologically standardized phototherapeutic that could theoretically be helpful to public health. The main aim of this correspondence is to review the preclinical information currently available on various parts of the Brassica juncea plant and to show some of the fascinating therapeutic possibilities that its edible section could bring.
... After initiation, the interwoven hyphae increase in size and finally it becomes mature by exterior delimitation, internal consolidation and melanization, which are later related with drop discharge. Sclerotia of S. sclerotiorum has the ability to develop in one or more ways namely carpogenic and myceliogenic, although carpogenic germination mostly found in S. sclerotiorum (Ekins et al., 2002;Hao et al., 2003;Clarkson et al., 2004). In myceliogenic germination, sclerotia in occurrence of exogenous nutrients can germinate and generate hyphae that directly infects living tissues of the host plant (Saharan and Mehta, 2008). ...
Brassica juncea (Indian mustard) is a major source of vegetable oil in India and cultivated as condiment, vegetable, and oilseed crop in different parts of the world. The seed quality of Indian mustard is mainly determined by the kind and proportion of its key components that include oil, protein and glucosinolates. Traditional mustard oil contains moderate levels of oleic acid which is important for oxidative stability of oil during cooking/storage and almost balanced ratio of nutritionally desirable linoleic and linolenic acids. However, its oil also contains significant proportion of erucic acid which causes serious cardiac problems. This very long chain fatty acid is considered good for various industrial purposes. Defatted seed meal obtained after oil extraction is valued for animal nutrition as a rich source of protein but presence of anti-nutritional components i.e., high glucosionlates limits its utilisation. Therefore, Development of productive germplasm coupled with improved seed quality is a prime breeding objective in mustard breeding. Concomitant improvement for all these interrelated traits is a mammoth task due to their complex inheritance patterns and large environmental influences. In this chapter, we review various conventional breeding approaches along with modern biotechnological interventions to improve the seed quality traits for nutritional and industrial purposes in Indian mustard.
... Phytopathogenic fungal identification was monitored according to [15]. Moreover, Fusarium and Sclerotinum species are identified according to [16,17] respectively. ...
In the present study, two phytopathogenic fungi were
isolated from Phaseolus vulgaris L. Macroscopic and
microscopic identification of the fungi attributed them to
the genera Fusarium and Sclerotinia. Antifungal activities of
three Pseudomonas strains; P7 Pseudomonas plantarii P30,
P. fluorescens Biovar 5 and P36 P. fluorescens Biovar 5
revealed percent inhibition of the phytopthogenic fungi
ranging from 47.78% to 100%. The determination of the
antifungal mechanism of the strain P7 revealed a mycelium
lysis of Sc-sc (Sclerotinia sclerotiorum) and deformation of
Fop (Fusarium oxysporum f sp. phaseoli). The results lead us
to think on the capability of utilization of the three strains
as biocontrol agents against the phytopathogenic fungi.
... Phytopathogenic fungal identification was monitored according to [15]. Moreover, Fusarium and Sclerotinum species are identified according to [16,17] respectively. ...
In the present study, two phytopathogenic fungi were isolated from Phaseolus vulgaris L. Macroscopic and microscopic identification of the fungi attributed them to the genera Fusarium and Sclerotinia. Antifungal activities of three Pseudomonas strains; P7 Pseudomonas plantarii P30, P. fluorescens Biovar 5 and P36 P. fluorescens Biovar 5 revealed percent inhibition of the phytopthogenic fungi ranging from 47.78% to 100%. The determination of the antifungal mechanism of the strain P7 revealed a mycelium lysis of Sc-sc (Sclerotinia sclerotiorum) and deformation of Fop (Fusarium oxysporum f sp. phaseoli). The results lead us to think on the capability of utilization of the three strains as biocontrol agents against the phytopathogenic fungi.
... Phytopathogenic fungal identification was monitored according to [15]. Moreover, Fusarium and Sclerotinum species are identified according to [16,17] respectively. ...
The strain HLA was identified as Bacillus amyloliquefaciens. Colonies were small and growth rapidly on TSA medium. Microscopic observation with Gram staining and epi-fluorescence revealed Gram positive and long bacilli bacteria. Strain HLA 16S rDNA similarities to the respective species were greater than (79 %). The phylogenetic analysis grouped Strain HLA with strain Bacillus amyloliquefaciens NR 117946.1 (95 %) and two strains of Bacillus subtilis NR113265.1 and NR112116.1 (95%). Strain HLA showed positive results for production of lecithinase, gelatinase and amylase. Inoculation of Phaseolus vulgaris L seed with Bacillus amyloliquefaciens HLA resulted on significative growth stimulation of plantules compared to the control, within 21 days of culture in pots. Bacillus amyloliquefaciens HLA increased, stem length (34.08 %), leaves area (96.5 %), root fresh weight (46.15 %) and root dry weight (70.41 %).
