Assessment of Groundnut Germplasm Lines for Foliar Fungal Diseases and Population Structure Analysis using Gene Based SSR Markers| Chapter 11 | Research Developments in Science and Technology Vol.4

Introduction: Peanut (Arachis hypogaea L.) is a valuable income crop with several uses for each plant component. Groundnut rust and late leaf spot (LLS) are two major foliar fungal diseases that can reduce yields by up to 70%. Fungicide use is costly and harmful to the environment; thus, developing new cultivars with genetic resistance is a more sustainable, environmentally friendly, and cost-effective way.

The goal of this study was to use allele specific molecular markers to screen groundnut germplasm lines for foliar fungal infections (LLS and rust).

The current study included 30 uncharacterized germplasm lines and four peanut check variants. Groundnut germplasm lines were screened against foliar fungal diseases such as LLS and rust using a set of four gene-based SSR molecular markers.

Results: A total of 14 alleles were found for polymorphic SSR markers, with an average of 3.5 alleles per locus. The gene diversity and Polymorphic Information Content (PIC) values varied from 0.3972-0.5778, with an average of 0.47. The genetic relationships between peanut genotypes are represented in a UPGMA tree based on SSRs. Based on origin, four primary demographic groupings were constructed using principal coordinate analysis (PCA). STRUCTURE v2.3.3 software based on SSR markers was used to examine the population structure of the 34 genotypes. Structure Harvester was used to find the optimum K value, and the largest peak was found at delta K = 2. Based on maximum likelihood and delta K (dK) values, a total of K subpopulations (K) were discovered, with two core and pure groups and an admixture group. AH8054, CS21181, CS708, and Akola White were discovered as four germplasm lines that might be exploited as foliar disease resistant cultivars for groundnut hybridization and improvement.

Author(s) Details:

Punam Chand Bhawar,
Department of Plant Molecular Biology and Biotechnology, College of Agriculture, Rajmata Vijayraje Scindia Agricultural University, Gwalior 474002, India.

Sushma Tiwari,
Department of Plant Molecular Biology and Biotechnology, College of Agriculture, Rajmata Vijayraje Scindia Agricultural University, Gwalior 474002, India.

M. K. Tripathi,
Department of Plant Molecular Biology and Biotechnology, College of Agriculture, Rajmata Vijayraje Scindia Agricultural University, Gwalior 474002, India.

R. S. Sikarwar,
Department of Genetics & Plant Breeding, College of Agriculture, RVS Agricultural University, Gwalior, 474002 M. P, India.

R. S. Tomar,
Rani Laxmibai Central Agricultural University, Jhansi, India.

Niraj Tripathi,
Directorate of Research Services, Jawaharlal Nehru Agricultural University, Jabalpur 482004, India.

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Microsymbionts Isolated from Pea Root Nodules – the Study of Population Diversity | Chapter 2 | Current Research Trends in Biological Science Vol. 2

Aims: The study of strains belonging to local rhizobial population, concerning their diversity in the genetic, metabolic and symbiotic properties, and their prevalence in the microsymbiont population. Methodology: 257 rhizobial isolates recovered from nodules of five pea (Pisum sativum cv. Ramrod) plants grown at one site were classified using PCR-RFLP analysis of 16-23S rRNA ITS. After that, for representative group of 55 strains, 16-23S rRNA ITS region was sequenced, nodA-F region was analyzed by PCR-RFLP and sequencing, metabolic capabilities were studied using Biolog`s and growth tests and symbiotic performance in plant tests were assayed. Results: Individual plants were infected by numerous and diverse strains, however, in the entire sampled population of microsymbionts, only three large clusters of strains (one similar to Rhizobium pisi and two similar to Rhizobium leguminosarum) could be distinguished on the basis of PCR-RFLP and sequence analyses of 16S-23S rRNA ITS region. Rhizobium strains belonging to different groups varied in plasmid number and the amount of plasmid DNA, utilization of carbon and energy sources, growth on soil extract-based media and the ability for symbiotic plant growth promotion. The most numerous group of the isolates was characterized by the high plasmid DNA content, low number of utilized sugar substrates, and comprised numerous strains with low symbiotic efficiency. Conclusion: Sampled population of pea microsymbionts had its own characteristic structure with clearly distinguishable sub-populations, composed of numerous strains - probably descendants of a few old lineages, which diversified in the lapse of time. These strains are still competing during root nodule colonization, resulting in the symbiosis of individual pea plants with broad spectrum of different Rhizobium strains. 

Author(s) Details

Jerzy Wielbo
Department of Genetics and Microbiology, Maria Curie-Skłodowska University, Akademicka 19 Street, 20-033 Lublin, Poland.

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