Thumbnail Image

Thesis

Browse

20231
Reset filters
Subject: Genetics and Plant Breeding × Author: Manpreet Kaur × Start date: 2020 × Type: Thesis × Thesis Type: M.Sc ×
Reset filters

Search Results

Now showing 1 - 1 of 1
  • Thumbnail Image
    ThesisItemRestricted
    Promoter polymorphism and development of molecular markers for FAD2 genes associated with oleic acid content in Brassica juncea L.
    (Punjab Agricultural University, 2023) Manpreet Kaur; Sunayana
    This study was undertaken to investigate the functional copies of the FAD2 gene that contribute to the formation of high oleic acid through expression profiling in low and high oleic acid groups of B. juncea. Subsequently, the promoter region of the functional FAD2 gene was extracted and analysed to identify sequence variations within both LOA and HOA groups using multiple sequence alignment. Molecular markers were developed using the identified variability in the promoter region and then validated on the F2 population derived from the cross between LOA (RLC3) and HOA (HOJ 93-1) cultivars. Three distinct functional copies of the FAD2 gene are situated on chromosomes A05 (BjuA.FAD2.a2), B01(BjuB.FAD2.b1) and B05 (BjuB.FAD2.b2) in B. juncea. The gene expression of BjuA.FAD2.a2 and BjuB.FAD2.b2 exhibited a higher fold change value in comparison to low and high oleic acid genotypes. The expression of BjuB.FAD2.b1 gene has an almost similar expression in diverse oleic acid genotypes. For the functional characterization of the promoter region of the FAD2 gene HOJ 93-6, HOJ 93-1 and RLC3, having high and low oleic acid content were outsourced for re-sequencing. Multiple sequence alignment indicated nucleotide variation only for BjuA.FAD2.a2 and BjuB.FAD2.b1 gene. No nucleotide variation was detected within BjuB.FAD2.b2 gene. SSR and CAPS makers were designed to facilitate marker assisted selection for high oleic acid content. After the validation of markers on parents and the F2 population, three distinct classes were observed for inheritance studies. The first category was characterized by oleic acid content exceeding 58%, the second displayed intermediate oleic acid levels of 46-56% and the third category exhibited low oleic acid content ranging from 40% to 45%. Inheritance studies indicated that the regulation of oleic acid content was governed by two FAD2 gene copies which are present at the A05 and B01 chromosome.