Anastomosis Groups and Pathogenicity of<i>Rhizoctonia solani</i>and Binucleate<i>Rhizoctonia</i>from Potato in South Africa

Muzhinji, Norman; Truter, Mary R.; Woodhall, J. W.; Waals, J. E. van der

doi:10.1094/pdis-02-15-0236-re

Cited by 51 publications

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References 31 publications

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“…Within the same AG, Muzhinji, Truter, Woodhall, and van der Waals (2015) determined that the virulence may vary from one isolate to another isolate, which had consistency with the present study. Their study also showed that BN Rhizoctonia AG-R isolates were more virulent in causing stem canker and black scurf on potato than that of AG-A.…”

Section: Discussionsupporting

confidence: 87%

Characterization and pathogenicity ofRhizoctoniaspp. isolated from kiwifruit in the Middle and Eastern Black Sea region of Turkey

Türkkan

Erper

Kılıçoğlu

et al. 2018

Journal of Phytopathology

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In this study, 58 Rhizoctonia isolates were obtained from plants exhibiting symptoms of root and stem rot in kiwifruit orchards in six different provinces in the Black Sea region of Turkey. The isolates were analysed for their cultural characteristics, anastomosis groups (AGs) and subgroups according to nucleotide sequence variations in the internal transcribed spacer (ITS) regions including the 5.8S gene of nuclear ribosomal DNA (rDNA) and pathogenicity. Based on ITS1‐5.8S‐ITS2 rDNA sequencing, 52 binucleate (BN) Rhizoctonia isolates were identified as belonging to AG‐O (17), AG‐L (1), AG‐G (7), AG‐I (1), AG‐A (9), AG‐Fa (9), AG‐Fb (1), AG‐R (3) and AG‐P (4). Of the remaining 6 isolates, three belonged to multinucleate (MN) R. solani AG 4 HG‐I, one belonged to AG 4 HG‐II, one belonged to AG 5 and one belonged to AG 1‐IB. The sequences of these isolates were aligned and compared with other Rhizoctonia sequences retrieved from GenBank (NCBI), and phylogenetic analysis was used to determine evolutionary relationships among them. All isolates used in the temperature experiments grew between 15–35°C, and their growth was completely inhibited at 5 and 40°C, with a few exceptions. In the pathogenicity tests carried out using 58.6% of the isolates on kiwifruit seedlings, it was determined that there were statistically significant virulence differences among BN and MN Rhizoctonia isolates (p < 0.05). The virulence of BN Rhizoctonia ranged from 0.2 to 4.0, whereas that of MN varied from 2.4 to 4.0. Unlike some isolates of AG‐R, AG 4 HG‐II and AG 1‐IB, which had no significant difference between them in virulence, AG‐P and AG 4 HG‐I isolates significantly reduced plant height, shoot and root dry weights and root length when compared to control plants. To our knowledge, it is the first detailed report of AGs of BN and MN Rhizoctonia, the causal agent of root and stem rot on kiwifruit in Turkey and in the world.

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Section: Discussionsupporting

confidence: 87%

Characterization and pathogenicity ofRhizoctoniaspp. isolated from kiwifruit in the Middle and Eastern Black Sea region of Turkey

Türkkan

Erper

Kılıçoğlu

et al. 2018

Journal of Phytopathology

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“…The AG identity of the isolates was confirmed by DNA sequencing of the internal transcribed spacer region (ITS) as described in a separate study (Muzhinji et al 2015). Soil-borne inoculum was prepared according to the method of Atkinson et al (2010) homogenized by blending in 4 L of sterile water into slurry, mixed with 10 L of vermiculite and incubated for five weeks with shaking after every two days.…”

Section: Inoculum Preparationmentioning

confidence: 99%

“…Rhizoctonia diseases on stems and stolons were presented as a disease index (DI). Disease index for stems and black scurf were calculated as described previously (Muzhinji et al 2015).…”

Section: Inoculum Preparationmentioning

confidence: 99%

“…DNA extraction was done using the ZR soil microbe DNA kit TM (Zymo Research Corporation, Irvine CA, USA) according to the manufacturer's protocol recommendations. The identification of isolated AGs was done using rDNA ITS sequencing as described previously (Muzhinji et al 2015).…”

Section: Fungal Isolation and Dna Extractionmentioning

confidence: 99%

“…Rhizoctonia solani species complex exists in many different groups and presently, 13 anastomosis groups (AGs) are recognized, with many subgroups (Carling et al 2002). The predominance and aggressiveness of R. solani AG 3 potato-inf ecting subgroup (AG 3-PT) on potatoes has been confirmed in South Africa (Muzhinji et al 2015) and elsewhere (Das et al 2014;Fiers et al 2011;Woodhall et al 2007). …”

Section: Introductionmentioning

confidence: 99%

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Relative Contribution of Seed Tuber- and Soilborne Inoculum to Potato Disease Development and Changes in the Population Genetic Structure of Rhizoctonia solani AG 3-PT under Field Conditions in South Africa

et al. 2018

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Understanding the contribution of seed tuber-and soil-borne inocula of Rhizoctonia solani AG 3-PT in causing potato disease epidemics is an important step in implementing effective management strategies for the pathogen. A two-year study was conducted to evaluate the contribution of each source of inoculum using an integrative experimental approach combining field trials and molecular techniques. Two distinct sets of genetically-marked isolates were used as seed tuber-borne and soil-borne inocula in a mark-release-recapture experiment. Disease assessments were done during tuber initiation and at tuber harvest Both inoculuma sources were found to be equally important in causing black scurf disease, whereas soil-borne inocula appeared to be more important for root and stolon infection, and seed-borne inocula contributed more to stem canker. However, seed tuber transmitted genotypes accounted for 60% of the total recovered isolates when genotyped using three PCR-RFLP markers. The changes in population structure of the experimental 1 R. solani population over the course of the growing season and across two growing seasons were investigated using eight microsatellite markers. The populations at different sampling times were somewhat genetically differentiated as indicated by Nei's gene diversity (0.24 -0.27) and the fixation index (F ST ) . The proportion of isolates with genotypes that differed from the inoculants ranged from 13% to 16% in 2013 and 2014, respectively, suggesting the possibility of emergence of new genotypes in the field. Because both soilborne and tuber-borne inocula are critical, it is important to ensure the use of pathogen-free seed tubers to eliminate seed tuber-borne inoculum and the introduction of new genotypes of R. solani for sustainable potato production in South Africa.

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Cloning and sequence analysis of a serine protease gene from Rhizoctonia solani Kühn AG5

Xiling

Wen-yan

et al. 2021

Biotech and App Biochem

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The present study aimed to identify the subtilisin-like proteases (SLPs) of Rhizoctonia solani Kühn potentially involved in the virulence of this phytopathogenic fungus, which has 14 anastomosis groups (AGs) responsible for many crop diseases. Through mycelial microscope observation and strain identification of pathogenic fungus MS-3, it was determined to be R. solani AG-5. Both 5ʹ and 3′ rapid amplification of cDNA ends were used to clone the serine protease gene RsSLP from R. solani AG-5. The full-length obtained for RsSLP was 1714 bp with an open reading frame of 1587 bp, encoding a protein of 528 amino acids with a molecular mass of 55.8 kDa. This protein contained a predicted signal peptide for secretion but lacked a transmembrane domain or membrane anchor site.Bioinformatics analysis identified this protein as a serine protease with the Pep-tidase_S8 and Inhibitor_I9 characteristic domains of SLPs. Phylogenetic analysis suggested that frequent gene duplications of the SLPs occurred in R. solani (RsSLP), and RsSLP shares characteristic sequence features with virulence factors of other phytopathogenic fungi. Because the secretory serine protease RsSLP from R. solani AG5 is similar to the virulence factors of other phytopathogenic fungi, its identification will be helpful in studies considering the roles of these proteases in pathogen virulence.

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Anastomosis Groups and Pathogenicity ofRhizoctonia solaniand BinucleateRhizoctoniafrom Potato in South Africa

Cited by 51 publications

References 31 publications

Characterization and pathogenicity ofRhizoctoniaspp. isolated from kiwifruit in the Middle and Eastern Black Sea region of Turkey

Characterization and pathogenicity ofRhizoctoniaspp. isolated from kiwifruit in the Middle and Eastern Black Sea region of Turkey

Relative Contribution of Seed Tuber- and Soilborne Inoculum to Potato Disease Development and Changes in the Population Genetic Structure of Rhizoctonia solani AG 3-PT under Field Conditions in South Africa

Cloning and sequence analysis of a serine protease gene from Rhizoctonia solani Kühn AG5

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