The Gamma Green House (GGH) is a chronic irradiation facility located at MINT Tech Park, Nuclear Malaysia, Jalan Dengkil. GGH is used for induction of mutation in plants and other biological samples with low dose radiation over period of time depending on the nature and sensitivity of the plant species. Gamma Greenhouse facility at Malaysian Nuclear Agency comprises an open topped
irradiation area consisting of circular green house with 30 meters radius, control room and irradiator with interlock system. The irradiation source is a REVISS RSL6050 double encapsulated 800 Ci 137Cs (half-life 30.1 years for 137Cs) pencils and allowed to be exposed only when the entire 300 m diameter site is free from personnel. The irradiator system is secured by a sophisticated interlock system, which only allows the source to be exposed when all the prerequisite safety conditions are met, and automatically returns the source to the safe
storage position if any safety device is compromised.
Colour is one of the most important traits in orchids and has created great interest in breeding programmes. Gamma irradiation is an alternative way for generation of somaclonal variation for new flower colours. Phenotypic changes are usually observed during screening and selection of mutants. Understanding of targeted gene expression level and evaluation of the changes facilitate in the development of functional markers for selection of desired flower colour mutants. Four Dendrobium orchid sequences (NCBI accessions: AM490639, AY41319, FM209429 and DQ462460) were selected to design gene specific primers based on information for chalcone synthase (CHS) from NCBI database. Quantitative real-time PCR (qPCR) was used to understand flower colour expression quantitatively derived from the CHS gene activities in different flower tissues (petal and sepal) from control Dendrobium Sonia (red purple), mutant DS 35-1/M (purple pink) and mutant DS 35-WhiteA. It was found that expression of CHS gene was highest in sepals of white flowers and lowest in both sepals and petals of purple pink flowers. Genomic DNA was amplified and PCR products were sequenced, aligned and compared. Sequence variations of CHS partial gene in Dendrobium Sonia mutants with different flower colour showed that two protein positions have been changed as compared to the control. These non-synonymous mutations may have contributed to the colour alterations in the white and purple pink mutants. This paper describes important procedures to quantify gene expression such as RNA isolation (quantity and quality), cDNA synthesis and primer design steps for CHS genes.
Assessing performance and genetic diversity of the wild material of oil palm is important for
under- standing genetic structure of natural oil palm populations towards improvement of the
crops. This in-formation is important for oil palm breeding programs, and also for continued exsitu
conservation of the germplasm and breeding program in Malaysia. Mutation induction is one
of the approaches in creating variants for selection in the breeding program. In this study, the
effect of irradiated pollen towards pollen viability, bunches formation and number of
parthenocarpic fruits were evaluated. Elaies guineensis Jacq. pollens were exposed to series of
acute gamma radiation at dose 0, 10, 20, 40, 50, 100, 200, 300, 500, 100 and 2000 Gy . Pollen
viability and pollen tube formation were disrupted in which unable the pollen to reach the ovule.
At this stage, embryo was aborted towards formation of parthenocarpic fruits and rotten bunches.
The study suggested that at low levels of irradiation i.e. < 200 Gy, generative nucleus partially
damage and it is still maintaining capacity of fertilizing the egg cells for hybridization. It is
important for breeders in understanding this finding towards novel variants of oil palm via
mutation induction
Induced mutagenesis using gamma ray has been proven applicable to improve varieties of many genotypes of crop species. The effects of 60Co gamma ray dosage on growth and callus induction of nucellus segments of Citrus reticulata cv. limau madu were investigated. The nucelli were exposed to gamma rays at doses of 10, 20, 40, 60, 80, 100 and 120 Gy, followed by embryogenic callus (EC) induction on Murashige and Skoog medium supplemented with 500 mg L-1 malt extract (ME), 146 mM sucrose, 0.8% (w/v) agar and 13.3 µM benzyl amino purine (BAP). Survival, callus type and colour, degree of callus formation, time of callus formation and total fresh weight of callus varied among the treatments. All untreated explants (controls) survived and produced friable EC in the 2nd or 3rd week of culture, whereas the irradiated nucelli showed delayed response. EC derived from the nucelli irradiated at 10, 20 and 40 Gy appeared in the 3rd week of culture, whereas EC from the 60 and 80 Gy doses appeared in the 4th week. Exposure to higher doses (100 and 120 Gy) completely suppressed callus formation. After 35 days of culture, an average of 697 and 660 mg of EC were harvested from the nucelli irradiated at 10 and 20 Gy, respectively, which was higher than those at 40 Gy (441 mg), 60 Gy (436 mg) and 80 Gy (380 mg). EC were initiated and proliferated and subsequently regenerated into plantlets. DNA of plantlets from the 20, 40 and 60 Gy exposure were individually amplified and compared to the control for early detection of mutagenesis using retrotransposon, inter simple sequence repeat and markers related to seedlessness. No variants were observed from the plantlets produced.
Mushroom can be used as a biological indicator in assessing radiological impact on the
environment. Radiological effect would be reflected through morphological changes as well as
those changes at molecular level. For this purpose, a preliminary work was conducted, which
included DNA isolation, optimization of PCR parameters for Inter-Simple Sequence Repeat (ISSR)
and primers screening on Pleurotus sajor caju mushroom strains from Nuclear Malaysia’s
Sterifeed Mushrooms Collection Centre. In this work, DNA isolation technique from cap and stalk
of fruit body were optimized and quantified. It was found that stalk produced highest amount of
genomic DNA at 304.01ng/µl and cap at 149.00ng/µl. A total of 100 ISSR primers were tested and
51 primers were successfully amplified. These primers will be used further for dose response
evaluation and molecular profiling in mushroom species.