“Biochemical and PCR Based Molecular Marker Systems for Detecting DNA Polymorphism in Pigeonpea [Cajanus cajan (L.) Millsp.]”
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Date
2012-07
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jau,junagadh
Abstract
Pigeonpea (Cajanus cajan (L.) Millsp., Fabaceae, 2n=22) is one of the most important pulse crops of the world with genome size 1C= 833.07 Mbp. An experiment was conducted at Biotechnology Laboratory, Department of Genetics and Plant Breeding, J.A.U. Junagadh during 2011-2012 using 15 genotypes of pigeonpea with two main objectives: (i) Biochemical markers analysis through protein profiling using SDS-PAGE and three isoenzymes viz., Peroxidase, Esterase and Polyphenol oxidase and (ii) Molecular markers analysis through RAPD, ISSR and SSR primers.
The seed protein profile generated ten bands out of which five bands were shared polymorphic. The cluster analysis revealed two main clusters, cluster I and II with fourteen and one genotype, respectively. The isoenzymes analysis done at 13 DAG revealed that three monomorphic bands of peroxidase were observed with Rm values of 0.218, 0.269 and 0.494, whereas only one shared polymorphic band of esterase was detected (Rm = 0.041). Polyphenol oxidase (PPO) generated three monomorphic bands with Rm values of 0.143, 0.206 and 0.453. Isozymes studies showed very less polymorphism which cannot be used to distinguish the 15 genotypes of pigeonpea.
Twelve RAPD primers amplified a total of 70 bands/alleles in which 66 bands/alleles were polymorphic (94.28%) with average 5.5 bands per primer. Twelve unique polymorphic bands were observed by six RAPD primers viz., OPP 6, 13ES10AC24, 14ES10A25, 17ES10C28, 21ES10A32 and 20ES10A31. The PIC ranged from zero to 0.914, whereas RAPD primer index (RPI) ranged from zero to 11.88. Nine ISSR primers amplified a total of 60 bands ranged from 158 bp to 1584 bp and all the bands were polymorphic (100%) with an average of 6.67 bands per primer. Three unique polymorphic bands were observed by UBC 808, UBC 854 and UBC 840 primers. The PIC varied from 0.742 to 0.932 and ISSR primer index (IPI) ranged from 2.97 to 9.96 with an average of 5.65 per primer index. Cluster analysis of both RAPD and ISSR revealed two main clusters, cluster I and cluster II with eleven and four genotypes, respectively.
Ten SSR primers generated total 16 bands out of which 15 bands were polymorphic (93.75%) with fragments ranged from 60 bp to 328 bp. The PIC value ranged from zero to 0.5 with SSR primer index (SPI) varied from zero to one. Fifteen pigeonpea genotypes were grouped into two main clusters, cluster I and cluster II with twelve and three genotypes, respectively.
All the three molecular markers produced higher percentage of polymorphic loci in which ISSR showed higher polymorphism (100%) among 15 genotypes as compared to RAPD (94.28%) and SSR (93.75%). There was a significant and positive correlation of combined data with similarity coefficient of RAPD, ISSR and SSR data. The dendrogram constructed by combined data of RAPD, ISSR and SSR showed 12.6% to 89.2% similarity between pair of genotypes. The cluster analysis revealed the two main clusters I and II with eleven and four genotypes, respectively. The data revealed that molecular techniques are more accurate than biochemical markers, and can be used for genetic diversity analysis of pigeonpea genotypes.
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biotechnology