https://repository.seku.ac.ke/handle/123456789/179 Tue, 17 Mar 2026 23:48:02 GMT 2026-03-17T23:48:02Z https://repository.seku.ac.ke/handle/123456789/3514 Title: Antimicrobial, synergistic and antioxidant activities of tea polyphenols Authors: Koech, K. R.; Wachira, Francis N.; Ngure, R. M.; Wanyoko, J. K.; Bii, C. C.; Karori, S. M.; Kerio, L. C. Abstract: Polyphenols are secondary metabolites produced by tea plant, wh ich play multiple essential roles in plant physiology and have potential health proper ties on human health, mainly as antioxidants, anti-allergic, anti-inflammatory, anticancer, antihypertensive and antimicrobial agents. Microbial resistance has become an increasing global problem; there is a need to find out novel potent antimicrobial agents with alternativ e modes of action as accessories to antibiotic therapy. This study investigated the antimicrobial, synergistic and antioxidant properties of tea polyphenols. The synergistic effect of tea polyphenols in combination with conventional antimicrobial agents against clinical multidrug-resistant microorganisms has been investigated and valuable data generated on the potential synergistic pr operties of tea polyphenols. Tue, 22 Aug 2017 00:00:00 GMT https://repository.seku.ac.ke/handle/123456789/3514 2017-08-22T00:00:00Z https://repository.seku.ac.ke/handle/123456789/3317 Title: Evidence of late acting self incompatibility in tea Authors: Wachira, Francis N.; Kamunya., Samson K. Abstract: To develop sound breeding strategies, it is necessary to understand the reproductive biology and breeding systenls of a species. The consequences of inbreeding are particularly inlportant as they influence the choice of progenitors, breeding population size and seed orchard design. Though the tea species (C. sinensis (L.) O. Kuntze) is thought to have evolved a pre-zygotic ganletophytic self-incoll1patibility systenl to reduce incidences of selfing, upto 20% selfing was determined in some Kenyan tea gerlnplas111. Using the aniline blue fluorescence assay to study incompability, successful "self' pollen penetrations were observed though nlost did not result in successful fruit set. This 111ay indicate that tea has a late acting self-inco111patibility systenl (LSI) or ovarian sterility (OS) type of control of s~lfing. Data on fruit set indicated huge differences anlong the test genllplas111 indicating that self-fertility varies anlong tea genetic resources and that tea ll1ay best be regarded as a facultative out breeder. Wed, 15 Mar 2017 00:00:00 GMT https://repository.seku.ac.ke/handle/123456789/3317 2017-03-15T00:00:00Z https://repository.seku.ac.ke/handle/123456789/3238 Title: Molecular markers - New tools for an old science - The case of tea Authors: Wachira, Francis N. Abstract: Recent advances in molecular biology, principally in the development of the Polymerase Chain Reaction (peR) for amplifying DNA have resulted in powerful techniques, which have variously been used to aid tea (Camellia sinensis) breeding in Kenya. This paper discusses progress made in the use of molecular markers to determine the level, structure and origin of genetic diversity among populations of tea and to develop marker assisted selection strategies in tea breeding programmes. Mon, 06 Mar 2017 00:00:00 GMT https://repository.seku.ac.ke/handle/123456789/3238 2017-03-06T00:00:00Z https://repository.seku.ac.ke/handle/123456789/3124 Title: Transcriptome-based identification of drought responsive genes in the tea plan Authors: Wachira, Francis N.; Maritim, T. K.; Kamunya, S. M.; Mireji, P.; Mwendia, C.; Muoki, R. C.; Wamalwa, M.; Stomeo, F.; Martina, K. P. Abstract: Tea ( Camellia sinensis L. (O) Kuntze) is one of the most widely consumed beverages worldwide. Tea growing areas in Kenya often experience drought periods which cause accumulated soil water deficit. These adversely affect tea production and hence necessitate a need to develop drought-adapted tea cultivars that can withstand the stress challenge. Development of such cultivars can be facilitated by better understanding of genetic mechanisms underlying tolerance of the tea plant to water deficit. Tea plants respond to water deficit through poorly understood molecular processes. The present study was therefore, designed with the objective of identifying genes putatively conferring tolerance in the tea plant. Drought tolerant (TRFCA SFS150) and susceptible (AHP S15/10) tea cultivars, both 18-month old, were each separately exposed to water stress or control conditions of 18% and 34% soil moisture content, respectively, for three months in a randomized complete block (RCB) design with three replicates. Fresh shoots ( n = 5) were randomly selected and separately harvested from each treatment and replicate. Total RNA of the shoots were extracted, their mRNA reverse transcribed and sequenced on Roche 454 high-throughput pyrosequencing platform. Overall, 232,853 reads were generated. The reads were quality-filtered, trimmed and assembled into 460 long transcripts (contigs). Contigs were annotated using BLAST searches against similar proteins in the Arabidopsis proteome and blast2go against non-redundant database to determine gene ontologies. Drought-related genes including heat shock proteins (HSP70), superoxide dismutase (SOD), catalase (cat), peroxidase (PoX), calmoduline-like protein (Cam7) and galactinol synthase ( Gols4 ) were induced in plants exposed to drought. Additionally, the expressions of HSP70 and SOD were higher in the drought tolerant relative to the susceptible cultivar under drought conditions. Loci with known functional links to physiological and biochemical features of drought response appear to mediate tolerance to drought in C. sinensis. The loci present potential molecular markers for drought tolerance that can be explored through functional genomics to better understand molecular mechanisms underlying drought tolerance in C. sinensis Mon, 20 Feb 2017 00:00:00 GMT https://repository.seku.ac.ke/handle/123456789/3124 2017-02-20T00:00:00Z