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20161
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Subject: Genetics and Plant Breeding × Author: Amandeep Kaur × End date: 2019 × Start date: 2012 ×
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    Allele mining for phospholipase D locus to improve the rice bran quality
    (Punjab Agricultural University, Ludhiana, 2016) Amandeep Kaur; Kuldeep Singh
    Rice (Oryza sativa L.) is the most important staple food for a large part of the world’s population. Rice bran which is a by-product after milling is rich in oil (12–23%), proteins (14–16%), vitamins and crude fiber (8–10%). Rice bran oil is typically an oleic–linoleic type fatty acid and qualifies for good quality edible oil. The primary limitation of rice bran as a source of oil is the presence of highly active lipolytic enzyme Phospholipase D alpha1 (PLDα1) that increases free fatty acids content in the oil and causes the ‘stale flavor’ in the product. The wild relatives of rice constitute a major gene pool for rice improvement. In this study, sequence based allele mining of the gene PLDα1 (6.28 kb) was taken up in wild species of rice to identify potentially novel alleles for bran quality improvement. Differences in expression patterns were also investigated for potential correlation with sequence variation. A representative subset of 86 accessions belonging to 16 wild Oryza species and eight O. sativa cultivars were selected for this purpose. Alignment of the assembled sequence contigs relative to the Nipponbare reference (Os01g0172400) gene revealed the presence of 2555 variations (SNPs and InDels). Highest polymorhism at PLDα1 locus have been detected in the O.officinalis species. Expression profiles in immature grains generated by exon-specific qRT-PCR indicate significant differences in transcript abundance within as well as between the selected accessions and different 3’and 5’ truncated PLDα1 mRNA. Cis-elements identified in the upstream sequences showed variations relative to the reference in low expressing wild species accessions. These results suggest that potential PLDα1 allelic variants are defined by differential regulation at the levels of transcription initiation and/or mRNA splicing. The wild species accessions with variations in protein structures and low expression, identified in the present study, can be further utilized in the breeding programs to transfer desirable allele into elite lines through marker assisted selection.