Population analysis of Magnaporthe oryzae by using endogenous repetitive DNA sequences and mating-type alleles in different districts of Karnataka, India
Rice is the staple food crop of more than 60% of the population of the world. This crop suffers from blast disease caused by Magnaporthe oryzae. Information on the mating-type allele distribution and diversity of the pathogen population for the state of Karnataka, India is scanty. With this background, a total of 72 isolates of M. oryzae from rice in different districts of Karnataka were examined for identifying sexual mating alleles MAT1, MAT2 and understanding the genetic diversity based on DNA fingerprint of pot2, an inverted repeat transposon. Among 72 isolates, 44 isolates belonged to MAT1 type (male fertile) and 28 isolates were of MAT2 (female fertile) and there were no hermaphrodite isolates. In a given geographical location, only one mating type was identified. Results revealed that the isolates obtained from these regions are not sexually fertile showing predominant asexual reproduction. Hence, genetic variation observed in the pathogen may be mainly because of high copy number of transposons. A high copy number transposon, namely Pot2, was selected in our study to detect genetic diversity of the pathogen. Pot2 rep-PCR DNA fingerprinting profile showed 27 polymorphic bands with bands ranging in size from 0.65 to 4.0 kb and an average of 10 to 14 bands per isolate. Five distinct clusters were formed with two major, two minor, and one outlier. Clusters 4 and 5 are further subdivided into three sub-clusters. Some of the isolates belonging to clusters 3, 4, and 5 are interlinked as these locations are close to one another sharing common geographical parameters and boundaries. This knowledge on the sexual behavior and genetic diversity of M. oryzae is important with respect to breeding for disease resistance.
KeywordsMagnaporthe oryzae Mating type MAT1 MAT2 Pot2-TIR Genetic diversity
Authors are grateful to the Department of Plant Pathology, GKVK, UAS, Bangalore for providing the instrumentation facility to carry out molecular work. We are also thankful to Yuvaraja’s College, University of Mysore, Mysuru for providing the facilities for carrying out this research work.
DJ conducted the experiment, analyzed the data, and drafted the manuscript.
DJ, MKP, and NSD performed the phenotypic evaluation which helped to do data analysis.
MKP participated in the design of the study.
NSD designed and coordinated this study and revised the manuscript.
All authors have read and approved the final manuscript.
We thank the University Grants Commission, New Delhi for the financial support by sanctioning Major Research Project (F.No. 41-408/2012 (SR) dated July 2012) to carry out this Investigation
Compliance with ethical standards
This article does not contain any studies with human or animal subjects.
The authors declare that they have no competing interests.
- IRRI (1996) Standard evaluation system for rice. 4th (eds.), international rice research institute (IRRI), Los Banos, Philippines.pp52Google Scholar
- Kumar J, Zeiglerb RS (1995) Mating behavior of Magnaporthe grisea from central himalayas of India. Phytopathology 85:1201Google Scholar
- Mahesh HB, Meghana S, Shailaja H, Prasannakumar MK, Mahadevu P, Channabyregowda MV, Malali G (2016) Acquisition of the grasshopper retro transposon by rice Magnaporthe isolates indicates a dynamic gene flow between rice and non-rice Magnaporthe population. J Pathol & Microbiol 1:1011–1022Google Scholar
- Ou SH, Ayad MR (1968) Pathogenic races of Pyricularia oryzae originating from single lesions and monoconidial cultures. Phytopathology 58:179–182Google Scholar
- Rohlf FJ (1998) NTSYSpc Numerical Taxonomy and Multivariate Analysis System Version 2.0 User Guide. Applied Biostatistics Inc., Setauket, New York .pp 37Google Scholar
- White TJ, Bruns T, Lee S, Taylor J (1990) Amplification and direct sequencing of fungal ribosomal RNA genes for phylogenetics. In: Innis MA, Gelfand DH, Sninsky JJ, White TJ (eds) PCR protocols. A guide to methods and applications. Academic Press, San Diego, pp 315–322Google Scholar
- Zeigler RS, Tohme J, Nelson R, Levy M and Correa-Victoria FJ (1994) Lineage exclusion: A proposal for linking blast population analysis to resistance breeding, In: Zeigler RS, Leong SA and Teng PS (eds.), Rice blast disease, CAB International, Wallingford, Oxon, UK and International Rice Research Institute, Manila, pp.267–292Google Scholar