Sharma, Umanath (2024) Biotechnological approaches for propagation and germplasm enhancement of berry crops. Doctoral (PhD) thesis, Memorial University of Newfoundland.
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Abstract
Berry crops, including blueberries and lingonberries, have long been appreciated for diverse flavours and antioxidant properties. Micropropagation technology enhances berry crops cultivation, yet optimal strategies for genetic, epigenetic and antioxidant insights remain elusive. This research aims to explore micropropagation dynamics for maximal plant production, detect consequences of in vitro culture on genetic and epigenetic factors, quantify antioxidant properties and identify the relationship with genetic variants. The research started with a detailed review, delineating the nuances of genetic and epigenetic instabilities arising from alterations in the tissue culture microenvironment, emphasizing the critical need for strategies to exclude such variants in commercial micropropagation. Various methods for detecting these variants, ranging from morphological and biochemical to molecular markers, are explored and focussed on Vaccinium berry plants. Optimizing micropropagation techniques yielded promising outcomes. Callus emerged as a superior explant compared to shoot tip and nodal segments. Liquid culture in a bioreactor system surpassed semi-solid media, generating three to four times more shoots. Spectrophotometric analyses unravelled antioxidant complexities, revealing a significant decline in total phenolics, flavonoids, and antioxidant activity in tissue cultures. Surprisingly, mass spectrometric analysis revealed that tissue-cultured plants exhibited a several-fold increase in individual antioxidant compounds, such as proanthocyanidin A2 and cyanidin 3-galactoside, presenting a potential pathway for enhancing specific antioxidants through micropropagation. Subsequently, a comprehensive exploration into morphological, genetic and epigenetic responses to tissue culture conditions revealed morphological differences between cultivated and hybrid lingonberry. Although no genetic variation was detected between the tissue cultures and greenhouse-grown plants, DNA methylation, an epigenetic variation, was prominent in the tissue cultures. Finally, a novel genome-wide association study (GWAS) revealed several thousand single nucleotide polymorphisms (SNPs) present throughout the blueberry genome. Nine SNPs were significantly associated with antioxidant activity in blueberry, and functional annotation revealed three SNPs associated with hypothetical, predicted, and characterized proteins such as BTB/POZ and TAZ domain-containing proteins. Further investigation of six SNPs on the RNA central database revealed thousands of RNA hits spanning different types of RNA molecules, shedding light on the complex interplay of proteins and RNA in influencing antioxidant activity in blueberry. Collectively, the results presented in this dissertation should benefit berry growers, consumers and breeders through informed production and breeding strategies and deeper understanding of their biological phenomenon.
| Item Type: | Thesis (Doctoral (PhD)) |
|---|---|
| URI: | http://research.library.mun.ca/id/eprint/16698 |
| Item ID: | 16698 |
| Additional Information: | Includes bibliographical references -- Restricted until September 28, 2025 |
| Keywords: | tissue culture, Vaccinium, antioxidant properties, lingonberry and blueberry, epigenetics |
| Department(s): | Science, Faculty of > Biology |
| Date: | October 2024 |
| Date Type: | Submission |
| Library of Congress Subject Heading: | Blueberries--Genetics; Vaccinium vitis-idaea--Genetics; Antioxidants--Analysis; Vaccinium--Breeding; Plant tissue culture--Genetics; Berries--Micropropagation; Epigenetics |
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