Related Experiment Video
Updated: Apr 23, 2026
Visualizing Early Infection Sites of Rice Blast Disease Magnaporthe oryzae on Barley Hordeum vulgare Using a Basic Microscope and a Smartphone
Published on: March 17, 2023
Molecular characterization and screening for sheath blight resistance using Malaysian isolates of Rhizoctonia solani
Kalaivani Nadarajah1, Nurfarahana Syuhada Omar1, Marhamah Md Rosli2
1School of Environmental and Natural Resources Sciences, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, 43600 Bangi Selangor, Malaysia.
Abstract:
Two field isolates of Rhizoctonia solani were isolated from infected paddy plants in Malaysia. These isolates were verified via ITS-rDNA analysis that yielded ~720 bp products of the ITS1-5.8S-ITS4 region, respectively. The sequenced products showed insertion and substitution incidences which may result in strain diversity and possible variation in disease severity. These strains showed some regional and host-specific relatedness via Maximum Likelihood and further phylogenetic analysis via Maximum Parsimony showed that these strains were closely related to R. solani AG1-1A (with 99-100% identity). Subsequent to strain verification and analysis, these isolates were used in the screening of twenty rice varieties for tolerance or resistance to sheath blight via mycelial plug method where both isolates (1801 and 1802) showed resistance or moderate resistance to Teqing, TETEP, and Jasmine 85. Isolate 1802 was more virulent based on the disease severity index values. This study also showed that the mycelial plug techniques were efficient in providing uniform inoculum and humidity for screening. In addition this study shows that the disease severity index is a better mode of scoring for resistance compared to lesion length. These findings will provide a solid basis for our future breeding and screening activities at the institution.
Insights
Two Rhizoctonia solani strains from Malaysian paddy plants were identified as AG1-1A. These isolates showed resistance in rice varieties, indicating potential for breeding disease-resistant crops.
Area of Science:
- Plant Pathology
- Molecular Biology
- Agricultural Science
Background:
- Rhizoctonia solani causes significant damage to rice crops worldwide.
- Understanding strain diversity is crucial for developing effective disease management strategies.
- Previous research has identified various anastomosis groups (AGs) of R. solani, but specific Malaysian strains require detailed characterization.
Purpose of the Study:
- To isolate and identify Rhizoctonia solani strains from infected paddy plants in Malaysia.
- To determine the phylogenetic relationship of these isolates to known R. solani groups.
- To screen rice varieties for resistance against these identified R. solani strains using an efficient screening method.
Main Methods:
- Isolation of R. solani from infected paddy plants.
- Molecular identification using Internal Transcribed Spacer-ribosomal DNA (ITS-rDNA) sequencing.
- Phylogenetic analysis using Maximum Likelihood and Maximum Parsimony methods.
- Screening of twenty rice varieties using the mycelial plug method.
- Evaluation of disease severity using a disease severity index.
Main Results:
- Two R. solani field isolates (1801 and 1802) were successfully isolated and identified.
- ITS-rDNA sequencing and phylogenetic analysis confirmed these isolates belong to R. solani AG1-1A with 99-100% identity.
- Both isolates showed resistance or moderate resistance against rice varieties Teqing, TETEP, and Jasmine 85.
- Isolate 1802 exhibited higher virulence.
- The mycelial plug method proved efficient for uniform inoculation and humidity control.
- Disease severity index was found to be a superior scoring method over lesion length.
Conclusions:
- The identified Malaysian R. solani strains are closely related to AG1-1A.
- Certain rice varieties demonstrate promising resistance to these virulent strains.
- The mycelial plug technique and disease severity index are reliable tools for future rice breeding and screening programs.
- These findings provide a foundation for developing sheath blight resistant rice cultivars.
More Related Videos
09:05Tomato Root Transformation Followed by Inoculation with Ralstonia Solanacearum for Straightforward Genetic Analysis of Bacterial Wilt Disease
Published on: March 11, 2020
09:42Isolation and Selection of Entomopathogenic Fungi from Soil Samples and Evaluation of Fungal Virulence against Insect Pests
Published on: September 28, 2021