Zetty Norhana Balia Yusof

Enhancing somatic embryogenesis of Malaysian rice cultivar MR219 using adjuvant materials in a high-efficiency protocol

Enhancing of the efficient tissue culture protocol for somatic embryos would facilitate the engineered breeding plants program. In this report, we describe the reproducible protocol of Malaysian rice (Oryza sativa L.) cultivar MR219 through somatic embryogenesis. Effect of a wide spectrum of exogenesis materials was assessed in three phases, namely callogenesis, proliferation and regeneration. Initially, rice seeds were subjected under various auxin treatments. Secondly, the effect of different concentrations of 2,4-D on callus induction was evaluated. In the next step, the efficiency of different explants was identified. Subsequently, the effects of different auxins, cytokinins, l-proline, casein hydrolysate and potassium metasilicate concentrations on the callus proliferation and regeneration were considered. For the callogenesis phase, 2xa0mgxa0L−1of 2,4-D and roots were chosen as the best auxin and explant. In the callus proliferation stage, the highest efficiency was observed at week eight in the MS media supplemented with 2xa0mgxa0L−1 of 2,4-D, 2xa0mgxa0L−1 of kinetin, 50xa0mgxa0L−1 of l-proline, 100xa0mgxa0L−1 of casein hydrolysate and 30xa0mgxa0L−1 of potassium metasilicate. In the last phase of the research, the MS media added with 3xa0mgxa0L−1 of kinetin, 30xa0mgxa0L−1of potassium metasilicate and 2xa0mgxa0L−1 of NAA were selected. Meanwhile, to promote the roots of regenerated explants, 0.4xa0mgxa0L−1 of IBA has shown potential as an appropriate activator.

Enhancement of Thiamine Biosynthesis in Oil Palm Seedlings by Colonization of Endophytic Fungus Hendersonia toruloidea

Thiamine, or vitamin B1 plays an indispensable role as a cofactor in crucial metabolic reactions including glycolysis, pentose phosphate pathway and the tricarboxylic acid cycle in all living organisms. Thiamine has been shown to play a role in plant adaptation toward biotic and abiotic stresses. The modulation of thiamine biosynthetic genes in oil palm seedlings was evaluated in response to root colonization by endophytic Hendersonia toruloidea. Seven-month-old oil palm seedlings were inoculated with H. toruloidea and microscopic analyses were performed to visualize the localization of endophytic H. toruloidea in oil palm roots. Transmission electron microscopy confirmed that H. toruloidea colonized cortical cells. The expression of thiamine biosynthetic genes and accumulation of total thiamine in oil palm seedlings were also evaluated. Quantitative real-time PCR was performed to measure transcript abundances of four key thiamine biosynthesis genes (THI4, THIC, TH1, and TPK) on days 1, 7, 15, and 30 in response to H. toruloidea colonization. The results showed an increase of up to 12-fold in the expression of all gene transcripts on day 1 post-inoculation. On days 7, 15, and 30 post-inoculation, the relative expression levels of these genes were shown to be downregulated. Thiamine accumulation was observed on day 7 post-colonization and subsequently decreased until day 30. This work provides the first evidence for the enhancement of thiamine biosynthesis by endophytic colonization in oil palm seedlings.

Quantitative assessment of indica rice germination to hydropriming, hormonal priming and polyethylene glycol priming

2 CHILEAN JOURNAL OF AGRICULTURAL RESEARCH 76(1) JANUARY-MARCH 2016 4 OCTOBER DECEMBER 2016 Seed priming is a useful technique which improves seed germination parameters. The present investigation was conducted to evaluate some of the most important germination parameters such as total germination, germination rate, mean germination time, average speed, germination percentage (GP), germination vigor index (GVI), relative frequency, plumule fresh and dry weight, radical fresh and dry weight, plumule and radical length, leaf and root proline content of six indica rice (Oryza sativa L.) varieties, including MR219, MR219-4, MR219-9, MR220, MR159, and MR 211 under hydro-, hormonaland polyethylen glycol (PEG)priming conditions. The highest germination parameters were achieved under the hydro-priming treatment, at 18 h (100%), 6 h (100%), 18 h (90.3%), 12 h (91.6%), 18 h (86.6%), and 18 h (78.3%) for the genotypes MR219, MR219-4, MR2199, MR220, MR159, and MR211, respectively. The best germination feedback of the rice varieties under the hormonal priming were observed in 50 mg L abscisic acid (ABA), 10 mg L gibberellic acid-3 (GA3), 50 mg L indole-3-acetic acid (IAA), 50 mg L GA3, 100 mg L ABA, and 10 mg L GA3 for the genotypes MR219, MR219-4, MR219-9, MR220, MR159 and MR211, respectively. The rice varieties showed different responses to various levels of PEG in which MR219, MR219-4 and MR219-9 responded positively to higher PEG levels, while MR220, MR159 and MR211 showed better feedback under lower PEG concentrations. These outcomes comply with the higher tolerance of MR219, MR219-9 and MR219-4 varieties to drought stress.

The Effect of Oxidative Stress Towards The Expression of Thiamine Biosynthesis Genes (THIC and THI1/THI4) in Oil Palm (Elaeis guineensis)

Thiamine is known to be an important compound in human diet and it is a cofactor required for vital metabolic processes such as acetyl-CoA biosynthesis, amino acid biosynthesis, Krebs and Calvin cycle. Besides that, thiamine has been shown to be involved in plant protection against stress. In this study, the level of expression of THIC and THI1/THI4, the genes for the first two enzymes in the thiamine biosynthesis pathway were observed when oil palm (Elaeis guineensis) was subjected to oxidative stress. Primers were designed based on the consensus sequence of thiamine biosynthesis genes obtained from Arabidopsis thaliana, Zea mays, Oryza sativa, and Alnus glutinosa. Oxidative stress were induced with various concentrations of paraquat and samplings were done at various time points post-stress induction. The expression of THIC and THI1/THI4 genes were observed via RT-PCR and qPCR analysis. The expression of THIC was increased 2-fold, while THI1/THI4 gene transcript was increased 4-fold upon induction of oxidative stress. These findings showed that oil palm responded to oxidative stress by over-expressing the genes involved in thiamine biosynthesis. These findings support the suggestion that thiamine may play an important role in plant protection against stress.

Chemometrics-Assisted Shotgun Proteomics for Establishment of Potential Peptide Markers of Non-Halal Pork (Sus scrofa) among Halal Beef and Chicken

Authentication of meat is a global concern owing to meat adulteration with pork; however, no study, to date, has established a method to identify species-specific peptide markers for ascertaining adulterated meat. The present study aimed to describe chemometrics-assisted shotgun proteomics, which has recently been reported to establish potential peptide markers for non-Halal pork among Halal beef and chicken meat. To identify the potential peptide markers through peptide mass fingerprinting (PMF) analysis, chemometric analysis comprised principal component analysis and orthogonal partial least square-discriminant analysis, both of which proved statistically useful. Subsequently, through targeted tandem liquid chromatography-mass spectrometry (LC-MS) analysis, the primary structure of the identified peptide markers was revealed using the de novo identification approach. A decoy, randomised and concatenated database search program comprising MS-Fit and MS-Tag was used for PMF and targeted tandem LC-MS analysis, respectively. Results obtained using both PMF and targeted tandem LC-MS analysis complemented one another, indicating that these methods can yield consistent results to identify peptide markers together with chemometric analysis.

Changes in the expressions of thiamine biosynthesis genes (THIC and THI1/THI4) in oil palm (Elaies guineensis) as response to salinity stress

Thiamine or also known as vitamin B1, it is the first water soluble B-complex vitamin to be identified which plays an important role as both cofactor and non-cofactor. Its active form, thiamine pyrophosphate (TPP) is important as a cofactor for various types of enzymes involved in central metabolism. Besides that, thiamine has been shown to have a role in plant protection against stress. In this study, we investigated the expressions of the first two enzymes involved in thiamine biosynthesis pathway, THIC and THI1/THI4 when subjected to salinity stress induced by sodium chloride (NaCl) at various concentrations, namely, 0, 50, 150 and 200 mM. RT-PCR was conducted to amplify both gene transcripts and the intensities of the bands were analyzed by using the ImageJ software. Overall, there was an increase in expression for both THIC and THI1/THI4 gene transcripts upon stress application. For THIC, the highest level of expression was observed on day 7 for 50 mM NaCl treated oil palm seedling with an increase of up to 331%, while for THI1/THI4, the highest level of expression was 723% on day 3 when 200 mM NaCl was applied to the oil palm seedlings. These results obtained are in agreement with suggestions that thiamine plays an additional role in plant protection against stress as it may lead to an overexpression of thiamine in general.