Transcriptomic approach to discover genes for secondary metabolite biosynthesis in Moringa oleifera Lam. seeds

Date of Award

2017

Document Type

Thesis

Degree Name

Master of Science in Biology

Department

Biology

First Advisor

Panes, Vivian A., Ph.D.

Abstract

Moringa oleifera Lam. is a widely used crop that produces seeds with a plethora of benefits encompassing health, nutrition, and phytoremediation. These benefits are attributed to the compounds present in the seeds including bioactive compounds and secondary metabolites like phenylpropanoid, flavonoid, and alkaloid. Exploring the transcriptome of the seeds paves the way for the discovery the expressed secondary metabolites. Although various phytochemical researches reported the presence of the secondary metabolites in M. oleifera Lam. seeds, there is a lack of study at the genetic level. In the present study, RNA sequencing was used to analyze the transcriptome of the mature embryo of M. oleifera Lam. More than 41 million sequencing reads were generated and de novo assembled using Trinity and SOAP-de novo. Trinity assembly produces 177, 417 contigs, of which 52.73% (93,546 transcripts) were annotated using NCBI Non-redundant database. SOAP-de novo assembly produces 49, 170 contigs, of which 57.83% (28, 433 transcripts) were annotated using similar database. Biological pathway analysis through KEGG-KAAS revealed genes encoding 18 enzymes involved in the catalytic steps in phenylpropanoid pathway, 11 enzymes involved in the catalytic steps in flavonoid pathway, and 19 enzymes involved in the catalytic steps in alkaloid pathway. Based on gene ontology (GO) functions, highly expressed genes for secondary metabolites are mostly involved in catalytic activities, metabolic processes, and single-organism process. This suggests that the seeds of M. oleifera Lam. might have nutritional and pharmacological benefits. This study provides the first transcript profile and the candidate set of genes for the biosynthesis of major secondary metabolites phenylpropanoid, flavonoid, and alkaloids in M. oleifera Lam. seeds. Characterization of the transcriptome of the seeds aids in establishing secondary metabolite pathways and for the discovery of the expressed secondary metabolites which may serve as a baseline information in future genetic and molecular research in improving the yield and quality of secondary metabolites in M. oleifera Lam. seeds.

Comments

The B5.D56 2017

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