Characteristics of in vitro- and ex vitro-propagated blueberry plants at morphological, chemical and molecular levels

The lowbush blueberry (Vaccinium angustifolium Ait.), a commercially important fruit crop in Canada and USA, is one of the richest sources of antioxidant metabolites which have highly potential to reduce the incidence of several degenerative diseases. The aim of this study is to investigate the effect of propagation on the morphological, chemical and molecular characteristics of blueberries. The study evaluated the genetic and epigenetic variation in micropropagated plants. A lowbush wild clone ‘QB9C’ and the cultivar ‘Fundy’ were studied after being propagated by conventional softwood cutting (SC), and by tissue culture (TC) using nodal explants. The antioxidant metabolites in leaves and fruits of both genotypes were investigated in different maturity stages. The TC-regenerated plants were grown more vigorously and produced higher number of stems, branches, and larger leaves compared to SC plants. However, TC plants of both genotypes produced less flowers and fruits compared with SC counterparts. Micropropagation influenced the synthesis of phenolic and flavonoid compounds, and their antioxidant activities in blueberry which were genotype specific. ‘QB9C’ plants were highly influenced by micropropagation for their phytochemical content and antioxidant capacity. Leaves contained substantially higher levels of polyphenolics, flavonoids and proanthocyanidins than berries. The total soluble phenolic and flavonoid content and reducing power of ferric ion were boosted in fruits of the micropropagated plants, whereas the levels of these metabolites and total antioxidant activity were decreased in the leaves of TC plants. Red leaves had higher phenolic and flavonoid content and antioxidant potential than the green leaves, and green fruits had higher levels of bioactive phytochemicals than semi-ripe and full ripe berries. In contrary, anthocyanin content increased with the advancement of fruit maturity. Molecular marker analysis with expressed sequence tag (EST)-simple sequence repeat (SSR) and EST-polymerase chain reaction (PCR) makers detected the identical monomorphic amplification profiles within the TC plants of each genotypes which confirmed their genetic integrity. Methylation sensitivity amplification polymorphism (MSAP) analysis demonstrated that TC plants of both genotypes had higher DNA methylation compared to SC plants. Discrete methylation polymorphism was observed among the tissue culture regenerated plants. These results indicate that although in vitro derived plants maintained trueness-to-type genetic makeup, tissue culture induces DNA methylation alterations and the possibility of involvement of these DNA fragments in the dynamic processes regulating plant growth and development under prevailing growth conditions

Tissue culture approaches to improve nutritional quality and stress response in peanut

Peanut, also known as groundnut (Arachis hypogaea L.), is an annual leguminous oil crop cultivated worldwide for food and fodder. Several stress factors critically diminish the productivity and nutritional quality of this protein-rich plant. In vitro cell and tissue culture systems have been used in many plant species to rapidly propagate large numbers of plants, create somaclonal variation, produce bioactive compounds, and enable genetic engineering. Tissue culture based mutagenesis and genetic engineering are particularly attractive for crop improvement. Tissue culture techniques have been implicated over the years to improve peanut, despite the general recalcitrant nature of this species to in vitro culture. In this manuscript, we review the progress that has been made on in vitro culture of peanut, and its application to improve nutritional quality and resistance to major biotic and abiotic stresses in peanut. DOI: http://dx.doi.org/10.5281/zenodo.509185

DNA-Based Molecular Markers and Antioxidant Properties to Study Genetic Diversity and Relationship Assessment in Blueberries

Blueberries (Vaccinium L. spp.) are an economically and medicinally important plant. Their antioxidant properties are well-known for their medicinal value in negating the harmful effects of free radicals. It is very important to develop genotypes that are high in health-promoting factors and economic value to meet present world needs. Estimation of genetic diversity using molecular markers, antioxidant properties, and their association can reveal genotypes with important characteristics and help in berry improvement programs. Wild blueberries are a better source of antioxidant metabolites compared to cultivated ones. Extensive variations are present in molecular and biochemical contents among wild clones and cultivars. The current review provides detailed and updated information on the economic and medicinal importance of blueberries, the application of molecular markers, and biochemical estimation in berry improvement and conservation, filling the gap in the literature

The Response of Cowpea (Vigna unguiculata) Plants to Three Abiotic Stresses Applied with Increasing Intensity: Hypoxia, Salinity, and Water Deficit

Exposing plants to gradually increasing stress and to abiotic shock represents two different phenomena. The knowledge on plants’ responses following gradually increasing stress is limited, as many of the studies are focused on abiotic shock responses. We aimed to investigate how cowpea (Vigna unguiculata (L.) Walp.) plants respond to three common agricultural abiotic stresses: hypoxia (applied with the increasing time of exposure to nitrogen gas), salinity (gradually increasing NaCl concentration), and water deficit (gradual decrease in water supply). We hypothesized that the cowpea plants would increase in tolerance to these three abiotic stresses when their intensities rose in a stepwise manner. Following two weeks of treatments, leaf and whole-plant fresh weights declined, soluble sugar levels in leaves decreased, and lipid peroxidation of leaves and roots and the levels of leaf electrolyte leakage increased. Polyphenol oxidase activity in both roots and leaves exhibited a marked increase as compared to catalase and peroxidase. Leaf flavonoid content decreased considerably after hypoxia, while it increased under water deficit treatment. NO emission rates after 3 h in the hypoxically treated plants were similar to the controls, while the other two treatments resulted in lower values of NO production, and these levels further decreased with time. The degree of these changes was dependent on the type of treatment, and the observed effects were more substantial in leaves than in roots. In summary, the responses of cowpea plants to abiotic stress depend on the type and the degree of stress applied and the plant organs.Science, Faculty ofNon UBCBotany, Department ofReviewedFacultyOthe