In vitro responses of dracaena fragrans cv. massangeana to growth regulators

In vitro studies on Dracaena fragrans cv. Massangeana revealed that young stem segments were capable of proliferating shoots on agar-solidified Murashige and Skoog (MS) basal medium containing different combinations and concentrations of BAP and NAA. Highest percentage of explants forming shoots was obtained on medium supplemented with 3.0 mgll BAP and 0.1 mgll NAA. The highest number ofshoots per explant occurred on medium containing 2.0 mgll BAP only. Highest percentage of callus formation and highest mean fresh weight of callus from young stem segments were achieved on MS medium supplemented with 1.0 mgll2,4-D. Adventitious rooting occurred after transferring excised shoots onto a hormone-free MS medium. Rooting was 100% for shoots derived from media with 0-2.0 mg/l BAP and a relatively low concentration of NAA (0.1 mg/l)

Growth, Water Relations and Physiological Changes of Young Durian (Durio zibenthinus Murr) as Influenced by Water Availability

The effects of water availability on durian clones D24, D99 and MDUR79 were investigated in two different experiments. In the first experiment, plants were exposed to different water availability: 80%; 40% and 10% of the field capacity. Water deficit reduced vegetative growth, water status and rate of photosynthesis in the plants. There was evidence of clonal effect on photosynthesis rate where clone D99 showed higher photosynthesis values than clone D24. In the second experiment, plants of D24, D99 and MDUR 79 were exposed to a duration of water stress ranging from 7 to 21 days. Plant water status and photosynthesis rate were more reduced by water deficit in the D24 than D99 or MDUR79. Higher proline accumulation in D99 and MDUR 79 clones suggested that both clones were more tolerant to water stress than clone D24

Metal inducible activity of the oil palm metallothionein-like gene promoter (MT3-A) in prokaryotes.

Reporter gene activity under the regulation of the oil palm metallothionein-like gene, MT3-A promoter was assessed in prokaryotes. Vector constructs containing MT3-A promoter with (W1MT3-A) and without (W2MT3-A) five prime untranslated region (5'-UTR) fused to ß-glucuronidase (GUS) gene in pCAMBIA 1304 vector were produced. 5'-rapid amplification of cDNA ends (RACE) using mRNA isolated from Escherichia coli and Agrobacterium tumefaciens harboring W1MT3-A confirmed that fusion transcripts of MT3-A 5'-UTR-GUS were successfully produced in both bacteria. Competitive PCR and GUS fluorometric assay showed changes in the level of GUS gene transcripts and enzyme activity in response to increasing concentrations of Cu²+ and Zn²+. The application of Cu²+ increased GUS activity and GUS mRNA level in both bacteria. In E. coli, a high level of GUS activity driven by W1MT3-A and W2MT3-A was observed in treatment with 25 μM Cu²+ resulting in an increase in the GUS mRNA level to 7.2 and 7.5 x 10⁻⁴ pmol/μl respectively, compared to the control (5.1 x 10⁻⁴ pmol/μl). The lowest GUS activity and GUS mRNA level were obtained for W1MT3-A and W2MT3-A in the presence of 100 μM Cu²+ in both bacteria compared to the control (without Cu²+). The application of different Zn²+ concentrations resulted in a strong decrease in the GUS activity and GUS mRNA level in E. coli and A. tumefaciens. These findings showed that the oil palm MT3-A promoter is functional in prokaryotes and produced detectable GUS transcripts and enzyme activities. This promoter may potentially be used in prokaryotic systems which require metal inducible gene expression

Prolific plant regeneration through organogenesis from scalps of Musa sp cv. Tanduk

A prolific plant regeneration system using scalps derived from shoot tips of Musaspp. cv. Tanduk was developed. Highly proliferating scalps, produced after four monthly subcultures of shoot tip explant on Murashige and Skoog (MS) medium supplemented with 100 mM BAP and 1.0 mM IAA, were placed on MS basal medium supplemented with 1.0, 2.5 and 5.0 mM BAP. Rooting of shoots was assessed on hormone-free half strength and full strength MS media and on MS medium supplemented with 1.0, 5.0 and 10 mM IBA. Four types of potting media comprising of sand, peat, sand + top soil + goat dung (3:2:1 v/v) and top soil + sand (1:1 v/v) were evaluated during acclimatization of the plantlets. Prolific shoot regeneration from scalps was obtained on MS medium containing 2.5 mM BAP, at 9.61 and 40.6 shoots per explant after 4 and 8 weeks of culture, respectively. Meanwhile, the highest mean shoot height of 2.19 cm was attained on MS medium with 1.0 mM BAP after 8 weeks of culture. Full-strength MS medium supplemented with 5.0 mM IBA produced the highest mean number of roots per explant at 15.08, while the highest mean root length of 11.07 cm was obtained on hormone-free half strength MS medium at week 4 of culture. The highest plant survivability of 77.5% was achieved in potting medium consisting of top soil + sand + goat dung after 6 weeks of acclimatization. The plants were morphologically normal with vigorous stems and broad green leaves

An efficient Agrobacterium-mediated transformation of strawberry cv. camarosa by dual plasmid system

An Agrobacterium-mediated transformation method was applied to introduce the luciferase reporter gene under the control of the CaMV35S promoter in the pGreen0049 binary vector into strawberry cv. Camarosa. The in vitro regeneration system of strawberry leaves to be used in the transformation was optimized using different TDZ concentrations in MS medium. TDZ at 16 µM showed the highest percentage (100%) of shoot formation and the highest mean number of shoots (24) produced per explant. Studies on the effects of different antibiotics, namely timentin, cefotaxime, carbenicillin and ampicillin, on shoot regeneration of strawberry leaf explants showed the best shoot regeneration in the presence of 300 mg/L timentin and 150 mg/L cefotaxime. Assessment of the different factors affecting Agrobacterium mediated-transformation of strawberry with the luciferase gene showed the highest efficiency of putative transformant production (86%) in the treatment with no preculture, bacterial OD600 of 0.6 and the addition of 150 mg/L cefotaxime in the pre-selection and selection media. The presence of the luciferase gene in the plant genome was verified by the luciferase reporter gene assay, nested PCR amplification and dot blot of genomic DNA isolated from the young leaves of each putatively transformed plantlet

Assessment of antioxidant and cytotoxicity activities of saponin and crude extracts of Chlorophytum birivilianum

The present paper focused on antioxidant and cytotoxicity assessment of crude and total saponin fraction of Chlorophytum borivilianum as an important medicinal plant. In this study, three different antioxidant activities (2,2-diphenyl-1-picrylhydrazyl radical scavenging (DPPH), ferrous ion chelating (FIC), and β-carotene bleaching (BCB) activity) of crude extract and total saponin fraction of C. borivilianum tubers were performed. Crude extract was found to possess higher free radical scavenging activity (ascorbic acid equivalents 2578 ± 111 mg AA/100 g) and bleaching activity (IC50 = 0.7 mg mL−1), while total saponin fraction displayed higher ferrous ion chelating (EC50 = 1 mg mL−1). Cytotoxicity evaluation of crude extract and total saponin fraction against MCF-7, PC3, and HCT-116 cancer cell lines using 3-(4,5-dimethylthiazol-2-yl)-2,5 diphenyltetrazolium bromide (MTT) cell viability assay indicated a higher cytotoxicity activity of the crude extract than the total saponin fraction on all cell lines, being most effective and selective on MCF-7 human breast cancer cell line

Callus induction in pineapple (Ananas comosus L.) cv. Moris and Josapine.

The induction of callus from Meristemic Globular Bodies (MGB) of two pineapple cultivars, namely Moris and Josapine, under six concentration levels of auxin NAA and six concentration levels of 2,4-D in Murashige and Skoog solid media, was investigated. 2,4-D auxin treatments failed to induce calli in both cultivars. However, 53.71, 75.19 and 85.93 μM levels of auxin NAA caused calli induction in Moris while levels 32.22, 53.71 and 75.19 μM also induced calli Josapine. The percentage of MGB calli formation increased with increasing time of culturing. At 6 weeks of culturing, 83% of Moris MGB explants formed calli on 85.93 μM NAA, while 50% of Josapine MGB explants formed calli on 53.71 μM NAA. Calli cultures have been an essential tool in the in vitro selection of desirable plants under manipulated conditions and from in vitro mutations via somaclonal variation. More importantly, calli are increasingly used for the application of cellular level genetic modification techniques such as the Agrobacterium-mediated transformation, particle bombardment and protoplast isolation and fusion. In this study, auxin NAA successfully initiated and proliferated calli in Moris and Josapine globular meristemic cultures

In vitro mutagenesis of Etlingera elatior (Jack) and early detection of mutation using RAPD markers.

Mutation breeding techniques in combination with tissue culture and molecular marker methods provide a powerful tool for improvement of vegetatively propagated plants. The aim of this study was to develop a protocol for shoot regeneration and mutation induction of Etlingera elatior. The results of irradiation on in vitro buds of E. elatior showed LD50 to be 10 Gy, with the survival of explants being sharply reduced at this dosage. All 8 selected gamma irradiated regenerants were differentiated from the untreated control based on the banding patterns obtained using 9 primers, which generated 59 reproducible bands, whereby 35 (55.31%) were found to be polymorphic. Jaccard’s coefficient of similarity values ranging from 0.537 to 0.860 were indicative of the level of genetic variation among the mutants studied. For comparison between the potential lines (PL) and the control, a maximum similarity value(0.814) was observed in PL1 mutant, while the minimum value (0.537) was observed in PL7. In summary, a combination of irradiation, regeneration, multiplication, and random amplification of polymorphic DNA (RAPD) analysis for early screening of mutants can speed up the breeding program of E. elatior

Oil palm EgCBF3 conferred stress tolerance in transgenic tomato plants through modulation of the ethylene signaling pathway

CBF/DREB1 is a group of transcription factors that are mainly involved in abiotic stress tolerance in plants. They belong to the AP2/ERF superfamily of plant-specific transcription factors. A gene encoding a new member of this group was isolated from ripening oil palm fruit and designated as EgCBF3. The oil palm fruit demonstrates the characteristics of a climacteric fruit like tomato, in which ethylene has a major impact on the ripening process. A transgenic approach was used for functional characterization of the EgCBF3, using tomato as the model plant. The effects of ectopic expression of EgCBF3 were analyzed based on expression profiling of the ethylene biosynthesis-related genes, anti-freeze proteins (AFPs), abiotic stress tolerance and plant growth and development. The EgCBF3 tomatoes demonstrated altered phenotypes compared to the wild type tomatoes. Delayed leaf senescence and flowering, increased chlorophyll content and abnormal flowering were the consequences of overexpression of EgCBF3 in the transgenic tomatoes. The EgCBF3 tomatoes demonstrated enhanced abiotic stress tolerance under in vitro conditions. Further, transcript levels of ethylene biosynthesis-related genes, including three SlACSs and two SlACOs, were altered in the transgenic plants’ leaves and roots compared to that in the wild type tomato plant. Among the eight AFPs studied in the wounded leaves of the EgCBF3 tomato plants, transcript levels of SlOSM-L, SlNP24, SlPR5L and SlTSRF1 decreased, while expression of the other four, SlCHI3, SlPR1, SlPR-P2 and SlLAP2, were up-regulated. These findings indicate the possible functions of EgCBF3 in plant growth and development as a regulator of ethylene biosynthesis-related and AFP genes, and as a stimulator of abiotic stress tolerance