In vitro regeneration of lychee (Litchi chinensis Sonn.)

In vitro plantlet regeneration in the main commercial variety of lychee (Litchi chinensis Sonn. cv Tai So) in Mauritius was achieved from callus cultures derived from young, tender leaf explants on Murashige and Skoog (MS) medium. Callogenesis was obtained in all media supplemented with auxin, but was most prominent in media supplemented with 2,4 – D ( 1.5 mgL-1) with or without benzylamino purine and kinetin. Nodular compact callus obtained in the 2,4 – D and BAP treatment proliferated and differentiated into shoots .When transferred to MS medium supplemented with BAP (2.0 mgL-1) and IAA (3.0 mgL-1). Regenerated shoots produced prominent roots when transferred to MS medium supplemented with IBA (2.0 mgL-1). Regeneration was predominantly through organogenesis. Somatic embryogenesis was observed when callus growing on MS medium supplemented with 2,4–D (1.5 mgL-1) was transferred to medium devoid of 2,4-D. Key Words: Litchi chinensis, micropropagation, somatic embyogenesis. African Journal of Biotechnology Vol.3(11) 2004: 576-58

A simple, rapid and efficient method for the extraction of genomic DNA from lychee (Litchi chinensis Sonn.)

A simple, rapid and efficient method for isolating genomic DNA from lychee (Litchi chinensis Sonn.) was developed. This modified CTAB protocol include the use of 2 M NaCl, PVP, 5% mercaptoethanol and 80% ethanol in the extraction as well as reducing the centrifugation times during the separation and precipitation of the DNA. Isolated genomic DNA showed high purity and high quantity following restriction digestion analysis. Key Words: Litchi chinensis; genomic DNA isolation. African Journal of Biotechnology Vol. 3 (4), 2004: 253-25

A Study on the use of carrot juice in the tissue culture of Daucus carota

Effects of using carrot juice in the in vitro growth of Daucus carota were investigated. Callus was the only form of growth obtained after five weeks in culture. The increase in fresh weight, dry weight and moisture content of the explants with increasing concentration of carrot juice in the medium was much lower when compared to either the cytokinin benzyladenine (BA) and/or the auxin picloram. Spectrophotometric and chromatographic analyses revealed the presence of both indole-3-acetic acid (IAA) and abscissic acid (ABA) in the carrot juice, while gibberellic acid was absent. Key Words: Carrot juice; auxin; abscissic acid. African Journal of Biotechnology Vol. 3 (4), 2004: 248-25

Effects of medium support and gelling agent in the tissue culture of tobacco (Nicotiana tabacum)

This study was designed to examine the effects of different media supports, brands of agar and gelling agents in the tissue culture of Nicotiana tabacum. There were significant differences (P<0.05) in terms of fresh weight, dry weight and number of shoots produced between the supports used. Best response was obtained with liquid agitated medium. However, there were no significant differences (P<0.05) between the gelling agents in terms of fresh weight, dry weight and number of shoots produced. Investigation in the response of two different cultivars of Nicotiana tabacum, viz Amarello and Virginia NC 95, to different support media, revealed significant differences (P<0.05), especially in their regeneration capability in liquid agitated medium. The gelling agents were also analyzed for their chemical properties. Large differences were observed between the gelling agents. The non-agar gel, gelrite, one of the best gelling agent, had a high content of ash, copper, iron, magnesium and zinc compared to the others.Keywords : Media supports, gelling agents, agar brands, tissue culture, chemical analysis

GMO detection using a bioluminescent real time reporter (BART) of loop mediated isothermal amplification (LAMP) suitable for field use

<p>Abstract</p> <p>Background</p> <p>There is an increasing need for quantitative technologies suitable for molecular detection in a variety of settings for applications including food traceability and monitoring of genetically modified (GM) crops and their products through the food processing chain. Conventional molecular diagnostics utilising real-time polymerase chain reaction (RT-PCR) and fluorescence-based determination of amplification require temperature cycling and relatively complex optics. In contrast, isothermal amplification coupled to a bioluminescent output produced in real-time (BART) occurs at a constant temperature and only requires a simple light detection and integration device.</p> <p>Results</p> <p>Loop mediated isothermal amplification (LAMP) shows robustness to sample-derived inhibitors. Here we show the applicability of coupled LAMP and BART reactions (LAMP-BART) for determination of genetically modified (GM) maize target DNA at low levels of contamination (0.1-5.0% GM) using certified reference material, and compare this to RT-PCR. Results show that conventional DNA extraction methods developed for PCR may not be optimal for LAMP-BART quantification. Additionally, we demonstrate that LAMP is more tolerant to plant sample-derived inhibitors, and show this can be exploited to develop rapid extraction techniques suitable for simple field-based qualitative tests for GM status determination. We also assess the effect of total DNA assay load on LAMP-BART quantitation.</p> <p>Conclusions</p> <p>LAMP-BART is an effective and sensitive technique for GM detection with significant potential for quantification even at low levels of contamination and in samples derived from crops such as maize with a large genome size. The resilience of LAMP-BART to acidic polysaccharides makes it well suited to rapid sample preparation techniques and hence to both high throughput laboratory settings and to portable GM detection applications. The impact of the plant sample matrix and genome loading within a reaction must be controlled to ensure quantification at low target concentrations.</p

Histological Observations Of Callus Development In Young Leaf Explants Of Lychee (Litchi Chinensis Sonn.)

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Full Length Research Paper - In vitro regeneration of lychee (Litchi chinensis Sonn.)

In vitro plantlet regeneration in the main commercial variety of lychee (Litchi chinensis Sonn. cv Tai So) in Mauritius was achieved from callus cultures derived from young, tender leaf explants on Murashige and Skoog (MS) medium. Callogenesis was obtained in all media supplemented with auxin, but was most prominent in media supplemented with 2,4 - D ( 1.5 mgL-1) with or without benzylamino purine and kinetin. Nodular compact callus obtained in the 2,4 - D and BAP treatment proliferated and differentiated into shoots.When transferred to MS medium supplemented with BAP (2.0 mgL-1) and IAA (3.0 mgL-1). Regenerated shoots produced prominent roots when transferred to MS medium supplemented with IBA (2.0 mgL-1). Regeneration was predominantly through organogenesis. Somatic embryogenesis was observed when callus growing on MS medium supplemented with 2, 4-D (1.5 mgL-1) was transferred to medium devoid of 2, 4-D

Conservation of Beclardia macrostachya

Beclardia macrostachya is a critically endangered orchid species in Mauritius. Very low level of fruit set has  been attributed to contribute to the decline in its population. Surveys carried out in the different forest regions  reveal the occurrence of this orchid at only one location, Pigeon Wood, with a present population of only 75  individuals. Biological studies at Reunion Island reveal preferential adaptation to higher altitudes, evidenced by  observed differences in fertility rates at different forest areas. Taxonomic studies using morphological characters suggest the placement of Beclardia macrostachya within a group that includes Cryptopus elatus and Aerides lawrenceae. When cultured in vitro, leaf explants developed nodular mass which failed to develop into protocorm-like bodies (PLBs). However, embryo rescue proved to be an efficient way for micropropagation of this orchid with a high regeneration capacity. Breeding programs carried out in Mauritius yielded capsules and the latter were successfully cultured to generate PLBs which would subsequently grow into plantlets

Local Sugars Alternatives for Tissue Culture of Dendrobium Hybrid CV. Sonia

In developing countries, commercial exploitation of tissue culture technology is limited by high cost of production. An Assessment of the effectiveness of using low cost alternative sugars for the in vitro micropropagation of Dendrobium cv. Sonia was investigated. Protocom-Like Bodies (PLBs) were multiplied in Murashige and Skoog (MS) liquid medium with 3.0mgL-1 benzyl adenine (BA) and 15% (v/v) coconut water. After the fifth subculture, 48.9% of the PLBs showed abnormal growth and 17.0% turned brown. PLBs after the first subculture were transferred to solidified MS medium with 01.mgL-1 BA , 1.0 mgL-1 NAA, 15% (v/v) coconut water, 20gL-1 analytical grade sucrose and local sugars such as refined brown sugar, refined dark brown sugar, unrefined dark brown sugar, refined white sugar and super refined white sugar. No significant difference (p&gt;0.05) was observed between analytical grad sucrose and local sugars. Healthy PLBs were obtained on solidified MS media supplemented with 20gL-1 refined brown, refined dark brown, unrefined dark brown and super refined white sugars. Browning of PLBs was obtained on MS medium with 20gL-1 refined local white sugars. Results indicated that when local sugars are used, the cost incurred on the importation of analytical grade sucrose can be reduced by more than 99%.Keywords: sugars, Protocorm-like bodies, Murashige and Skoog medium, cos