Determination of morphometric, biochemical and genetic variation in Sclerotium delphinii isolates (original) (raw)
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Variability in Indian isolates of Sclerotium rolfsii
Mycologia
Variability among 26 isolates of Sclerotium rolfsii collected from various hosts/soil samples and localities in India is reported. The isolates varied in colony morphology, mycelial growth rate, sclerotium formation, teleomorph production and sclerotial size and color. Out of 26 isolates, only 4 produced the teleomorph stage on Cyperus rotundus rhizome meal agar medium. Mycelial incompatibility among the isolates was also seen, and out of 325 combinations, only 29 combinations (8.9%) showed compatible reactions. Based on mycelial compatibility, 13 vegetative incompatibility groups (VCG) were identified among the isolates. HPLC analysis of the ethyl acetate fraction of culture filtrates of the isolates revealed 10-22 peaks. Six peaks were identified as gallic, oxalic, ferulic, indole-3-acetic acid (IAA), chlorogenic, and cinnamic acids. Oxalic, IAA, and cinnamic acids were present in the culture filtrates of all the isolates in varying amounts. The other three phenolic acids were not...
Morphological and molecular diversity of Sclerotinia sclerotiorum infecting Indian mustard
Indian Phytopathology, 2018
Fourteen isolates of Sclerotinia sclerotiorum were collected from different locations of mustard growing regions of India and were studied for cultural, morphological and molecular variability at CCS HAU, Hisar. Variability was observed for colony colour, type of growth, diameter of mycelial growth, sclerotia initiation, number and pattern of sclerotia formation among the isolates. Mycelial growth and sclerotia initiation were faster in Bhiwani isolate as compared to others. Bhiwani isolate was found to be the most diverse and had least similarity with Chhanibari isolate on the basis of molecular variability. Hence, morphological and cultural variability observed in the present investigation is by and large strongly correlated to molecular marker based variability.
Iran. J. Plant Path, 2010
Sclerotinia stem rot caused by Sclerotinia sclerotiorum, is one of the most important disease of canola in Iran. Regarding to importance of this disease and the lack of comprehensive knowledge on genetic diversity of this pathogen in Iran, mycelia compatibility groupings (MCGs) and genetic variation among MCGs from Golestan, Mazandaran and western Azarbaijan provinces were examined. Sixty-four isolates were selected respecting to geographic distribution and their MCGs were determined. Among these tested isolates, 38 MCGs were identified. Pathogenecity tests were carried out in greenhouse and analysis of resulting data (lesion phenotype+lesion length+girdling) categorized isolates into three groups with different range of virulence. Our data indicated that virulence of isolates varied within one MCG and also between MCGs. Study of genetic diversity among MCGs (38 isolates representative of 38 MCGs), using banding pattern of four rep-PCR primers categorized isolates into seven groups at the 64% similarity level. Accordingly, majority of isolates were separated based on their geographic origin. The discriminatory power of rep-PCR genotyping (D = 0.993), which discriminated 37 different genotypes, was high, indicating that rep-PCR is a rapid, effective marker for genotyping S. sclerotiorum isolates.
Journal of Agriculture and Environment
Sclerotium rolfsii Sacc. is prevalent in leguminous and solanaceous crops but over the last five years, its severity has increased in several crops such as rice, onion and chilli in Nepal. A study on cross infectivity of S. rolfsii was carried out in March, 2019 at Agriculture and Forestry University, Chitwan. S. rolfsii were isolated from eight crop species viz. rice, lentil, rajma, onion, chickpea, rapeseed, soybean, and chilli. Cross infectivity of the eight isolates was done on the seven crop species in artificially inoculated soils in a screen house. Morphological characters such as mycelial growth rate, number of sclerotia formed, and size of sclerotia were studied. Morphological characters of the S. rolfsii varied among the isolates. All crop species tested were found to be susceptible to all isolates except onion isolate. Germination percentage was greatly reduced (80%) in rajma. Post emergence seedling mortality ranged between 10% in rice and chilli and 100% in chickpea, m...
Identification of Sclerotinia species
Australasian Plant Pathology, 2005
A variety of morphological and molecular characters were compared for their ability to separate the three plant pathogenic species that comprise the genus Sclerotinia: Sclerotinia sclerotiorum, Sclerotinia minor and Sclerotinia trifoliorum. Restriction fragment length polymorphism (RFLP) probes generated from cloned genomic DNA fragments of S. sclerotiorum were used for accurate species designation and to compare against other markers, before further use in population genetics and breeding studies. Other characters used for comparison included host species, sclerotial diameters, ascospore morphism and breeding type. Several RFLP probes, either singly or in combination, enabled clear separation of the Sclerotinia species. Sclerotial diameters remain a good criterion for separating S. minor from S. sclerotiorum and S. trifoliorum, but the host species criterion was inadequate for accurately differentiating the 3 species of Sclerotinia.
Australasian Plant Pathology, 2005
Damping-off and stem rot of cowpea caused bySclerotium rolfsii has previously been reported in Benin, where the pathogen showed variation in growth and sclerotia production among isolates. Pathogenicity, mycelial compatibility group (MCG) tests and rDNA sequence analyses were conducted on different isolates ofS. rolfsii and S. delphinii collected from different hosts and geographical areas in Benin and South Africa. All the isolates, when inoculated into soil and planted with cowpea, caused damping-off and stem rot symptoms. Aggressiveness among isolates varied depending on the host from which each was isolated. Isolates originating from cowpea produced the highest disease incidence followed by isolates from peanuts. Four MCGs were distinguished among 66 isolates. Isolates from the same hosts tended to group into the same MCG. The incidence of damping-off and stem rot of cowpea, expressed as percentage diseased plants, varied among MCGs. Plants inoculated with MCG2 displayed the highest disease incidence, whereas MCG4 resulted in the least. Parsimony analysis of ITS DNA sequence data supported a close affinity of the Sclerotium spp. but showed genetic variation among isolates with no grouping based on host of origin.
Genetic and Morphological Diversities in Sclerotinia sclerotiorum Isolates in Northern Parts of Iran
Abstract: Sclerotinia sclerotiorum is the most important causal agent of stem rot diseases on the field crops in Iran. During 2006-2007, totally 65 isolates of the fungus were obtained from infected rapeseed, lettuce, bean, tomato, cucumber and wild sinapsis plants in various fields of North provinces in Iran. Genetically diversities between the isolates were investigated by PCR, using five microsatellite primer pairs and those divided to 9 groups with 25 clear polymorphic alleles. A high level of genetic diversity was observed about 67%, between the some isolates. By mycelial compatibility grouping tests, the isolates were settled into 39 groups that 26 MCGs were individual. Molecular and phenotypic analyses results of the most of isolates were similar; however the isolates in MCG1, MCG4 and MCG23 groups, with variable microsatellite haplotypes, were morphologically dissimilar. The results shown that there were possibly high rates of out crossing as well as evolutionary potential w...
Journal of Integrative Plant Biology, 2005
The genetic diversity and genetic structure of a population of isolates of Sclerotinia sclerotiorum (Lib.) de Bary from different regions and host plants were investigated using the random amplified polymorphic DNA (RAPD) method with 20 random decamer primer pairs in order to provide some information on the phylogenetic taxa and breeding for resistance to sclerotinia stem rot. A minimum of three and a maximum of 15 unambiguously amplified bands were generated, furnishing a total of 170 bands ranging in size from 100 to 3 200 bp, corresponding to an average of 8.5 bands per primer pair. One hundred and four of these 170 bands (61.2%) were polymorphic, the percentage of polymorphic bands for each primer pair ranging from 0.0% to 86.7%. The genetic relationships among the isolates, based on the results of RAPD analysis, were examined. The genetic similarity of all selected isolates was quite high. At the species level, the genetic diversity estimated by Nei's gene diversity (h) was 0.197 and Shannon's index of diversity (I) was 0.300. The unweighted pair-group mean analysis (UPGMA) cluster analysis showed that most isolates from the same regions were grouped in the same cluster or a close cluster. The population of isolates from Hefei (Anhui Province, China) was more uniform and relatively distant to other populations. The Canadian population collected from carrot (Daucus carota var. sativa DC.) was relatively close to the Polish population collected from oilseed rape (Brassica napus L.) plants. There was no relationship between isolates from the same host plants. An analysis of molecular variance (AMOVA) revealed that the percentage of variance attributable to variation among and within populations was 50.62% and 49.38%, respectively. When accessions from China, Europe, and Canada were treated as three separate groups, the variance components among groups, among populations within groups, and within populations were -0.96%, 51.48%, and 49.47%, respectively. The genetic differentiations among and within populations were highly significant (P < 0.001). Similarly, the coefficient of gene differentiation (Gst) in total populations calculated by population genetic analysis was 0.229 4, which indicated that the genetic variation among populations was 22.94%. The gene flow (Nm) was 1.68, which indicated that the gene permutation and interaction among populations was relatively high. Key words: genetic structure; intraspecific variability; Sclerotinia sclerotiorum (Lib.) de Bary; random amplified polymorphic DNA (RAPD) analysis.
Genetic diversity among different isolates of Sclerotinia sclerotiorum in
2014
Sclerotinia sclerotiorum (Lib.) de Bary is a cosmopolitan, homothallic fungus, and is the most important causal agent of stem rot diseases in field crops of Iran. During 2011-2012, a total of 52 isolates of the fungus were collected from infected rapeseed plants (Brassica napus cultivar Hiola 401) from several fields of Northern Iran. The genetic diversity of S.sclerotiorum populations were assessed using Simple Sequence Repeat fingerprinting (SSR). By using five SSR primers, 27 haploid groups with 14 alleles polymorphism were detected. A high level of genetic diversity 52% was observed between isolates. The results showed that there were possibly high rates of out crossing, as well as, evolutionary potential within 52 isolates obtained from different geographical locations. The variability found within closely related isolates demonstrates the effectiveness of SSR marker in identifying genetic diversity. This is the first report on genetical diversity in S. sclerotiorum populations...
2016
Sclerotinia sclerotiorum is an ubiquitous plant pathogen responsible for a wide range of diseases among different vegetable crops with a host range of more than 400 plant species. It continues to be the most destructive plant pathogen for many years having no significant method for its control and management. In the present study, an attempt was made to isolate and characterize S. sclerotiorum from infected cauliflower and pea grown in Solan and Sirmaur districts of Himachal Pradesh, India. The isolates were characterized morphologically and molecularly by the amplification of the internal transcribed spacer region (ITS) using specific primers, followed by sequencing. The genetic diversity among the sixteen isolates of S. sclerotiorum was also studied using random amplified polymorphic DNA (RAPD). Four random primers, viz., OPA-14, OPA-16, OPA-17 and OPA-20 were used for RAPD analysis. Clustering based on RAPD fingerprint data revealed two groups and ten independent branches at 0.70...