Siam Popluechai

Accumulation of catechins in tea in relation to accumulation of mRNA from genes involved in catechin biosynthesis.

Catechins are a group of polyphenols found in tea (Camellia sinensis var. sinensis) at high levels. They are beneficial for health. From the study on accumulation of catechins in shoots and mature leaves of a tea cultivar, Oolong No. 17, using high-performance liquid chromatography (HPLC), it was found that the amounts of most catechins in the shoots were higher than those in the mature leaves, with an exception of catechins gallate (CG) that was found in trace amounts in both the shoots and mature leaves. mRNA accumulation of genes involved in catechin synthesis was studied using reverse transcriptase-polymerase chain reaction (RT-PCR). The results showed that the mRNA accumulation of the genes were higher in the shoots than in the mature leaves. These genes included genes of phenylalanine ammonia-lyase 1 (PAL1; EC 4.3.1.5), chalcone synthase (CHS; EC 2.3.1.74), dihydroflavonol 4-reductase (DFR; EC 1.1.1.219), leucoanthocyanidin reductase (LCR; EC 1.17.1.3), and flavanone 3-hydroxylase (F3H; EC 1.14.11.9).

Proteomic Perspectives on Understanding and Improving Jatropha curcas L.

Ninety percent of the world’s energy demands are met by non-renewable fossil fuels. The limited supply, high prices and non-sustainability of fossil fuels has led to exploring new resources for energy. Among all the available sources of renewable energy, biodiesel is viewed as one of the best alternatives, particularly for transport fuel, because it can provide a secure and economically viable source of energy. Biodiesel can be used directly or as an additive to petro-fuels as it can lessen harmful vehicle emissions which cause adverse environmental effects. Recent studies have shown non-edible oilseed crops such as Jatropha curcas to be suitable for biodiesel production. The by-products of J. curcas-based biodiesel production have numerous industrial applications. The different parts of the plant and its extracts can be used in medicinal, cosmetic, plastics and insecticide/pesticide industries. If realistic returns are expected, J. curcas can be grown on marginal and wastelands promoting effective land use and generating employment, thus strengthening local communities both socially and economically. However, neither J. curcas nor any other potentially useful non-edible oilseed plant is currently grown commercially. Genotypic characterization of the global accessions of J. curcas have shown limited genetic diversity despite appreciable variability in important phenotypic, physiological and biochemical traits. Further genetic improvement of J. curcas is desirable for improved oil quality and quantity, either through conventional breeding or molecular engineering, for a number of reasons. These include unpredictable yield patterns, varying but often low oil content, the presence of toxic and carcinogenic compounds, multiple asynchronous flowering flushes, plant height and problems associated with seed germination. Knowledge of the nuclear and chloroplast genome of J. curcas and standardization of plant transformation and gene silencing in this plant provide opportunities for rapid progress in understanding and improving the J. curcas potential as a biodiesel crop. This chapter reviews information specifically on proteins and proteome analysis based approaches to identify useful components in critical biochemical pathways or traits such as fatty acid metabolism, phorbol ester synthesis and stress tolerance. Identification of spatio-temporally specific and environmentally responsive proteins as the reactive component can compliment and fast-track other genomic and transcriptomic approaches for improving J. curcas.

Effects of 6-Benzyladenine on Jatropha Gene Expression and Flower Development

Jatropha curcas L. has been considered as a potential source of biodiesel feedstock due to its highly seed oil content. However, Jatropha exhibits low numbers of female flowers leading to insufficient seed yields for biodiesel production. Previous studies showed that application of 6-benzyladenine (BA) on Jatropha flower buds significantly increased female flower numbers and seed yield. However, the underlining molecular mechanism remained unclear. In this study, 160 mg/L of BA was applied on the Jatropha flower buds. As a result, BA significantly increased female flowers, male flowers, and seed yield (P < 0.05). BA also affected the inflorescences area, number and length of pedicel, all of which were appreciably greater than control (P < 0.05). The effect of BA to flower bud development was observed using Scanning Electron Microscope (SEM). SEM revealed that the stages of floral development between control and BA-treatment were similar indicating that BA might affect floral development at the transcriptomic level. Flower buds at 0, 4, and 24 h were selected based on the presence of sex organs for genes involved in flower development investigation. The expression analysis of 23 genes showed that CYTOKININ OXIDASE/DEHYDROGENASE5 (JcCKX5) was highly expressed at the transition stage (P< 0.05) subsequently enhanced the inflorescences area, increased organogenic capacity and ovule primordia formation. Moreover, application of BA increased the expression of SUPERMAN (JcSUP) and decreased the expression of TASSELSEED2 (JcTS2) during sex organs differentiated stage. Therefore, JcSUP might play a role in female flower formation parallel with arrested stamen formation through the down-regulation of JcTS2.

Transcriptome analysis of Jatropha curcas L. flower buds responded to the paclobutrazol treatment

Jatropha seeds can be used to produce high-quality biodiesel due to their high oil content. However, Jatropha produces low numbers of female flowers, which limits seed yield. Paclobutrazol (PCB), a plant growth retardant, can increase number of Jatropha female flowers and seed yield. However, the underlying mechanisms of flower development after PCB treatment are not well understood. To identify the critical genes associated with flower development, the transcriptome of flower buds following PCB treatment was analyzed. Scanning Electron Microscope (SEM) analysis revealed that the flower developmental stage between PCB-treated and control flower buds was similar. Based on the presence of sex organs, flower buds at 0, 4, and 24 h after treatment were chosen for global transcriptome analysis. In total, 100,597 unigenes were obtained, 174 of which were deemed as interesting based on their response to PCB treatment. Our analysis showed that the JcCKX5 and JcTSO1 genes were up-regulated at 4 h, suggesting roles in promoting organogenic capacity and ovule primordia formation in Jatropha. The JcNPGR2, JcMGP2-3, and JcHUA1 genes were down-regulated indicating that they may contribute to increased number of female flowers and amount of seed yield. Expression of cell division and cellulose biosynthesis-related genes, including JcGASA3, JcCycB3;1, JcCycP2;1, JcKNAT7, and JcCSLG3 was decreased, which might have caused the compacted inflorescences. This study represents the first report combining SEM-based morphology, qRT-PCR and transcriptome analysis of PCB-treated Jatropha flower buds at different stages of flower development.

High diversity of Blastocystis subtypes isolated from asymptomatic adults living in Chiang Rai, Thailand

Blastocystis is a common and broadly distributed microbial eukaryote inhabiting the gut of humans and other animals. The genetic diversity of Blastocystis is extremely high comprising no less than 17 subtypes in mammals and birds. Nonetheless, little is known about the prevalence and distribution of Blastocystis subtypes colonising humans in Thailand. Molecular surveys of Blastocystis remain extremely limited and usually focus on the central, urban part of the country. To address this knowledge gap, we collected stool samples from a population of Thai adults (n = 178) residing in Chiang Rai Province. The barcoding region of the small subunit ribosomal RNA was employed to screen for Blastocystis and identify the subtype. Forty-one stool samples (23%) were identified as Blastocystis positive. Six of the nine subtypes that colonise humans were detected with subtype (ST) three being the most common (68%), followed by ST1 (17%) and ST7 (7%). Comparison of subtype prevalence across Thailand using all publicly available sequences showed that subtype distribution differs among geographic regions in the country. ST1 was most commonly encountered in the central region of Thailand, while ST3 dominated in the more rural north and northeast regions. ST2 was absent in the northeast, while ST7 was not found in the center. Thus, this study shows that ST prevalence and distribution differs not only among countries, but also among geographic regions within a country. Potential explanations for these observations are discussed herewith.

Urban Diets Linked to Gut Microbiome and Metabolome Alterations in Children: A Comparative Cross-Sectional Study in Thailand

Loss of traditional diets by food globalization may have adverse impact on the health of human being through the alteration of gut microbial ecosystem. To address this notion, we compared the gut microbiota of urban (n = 17) and rural (n = 28) school-aged children in Thailand in association with their dietary habits. Dietary records indicated that children living in urban Bangkok tended to consume modern high-fat diets, whereas children in rural Buriram tended to consume traditional vegetable-based diets. Sequencing of 16S rRNA genes amplified from stool samples showed that children in Bangkok have less Clostridiales and more Bacteroidales and Selenomonadales compared to children in Buriram and bacterial diversity is significantly less in Bangkok children than in Buriram children. In addition, fecal butyrate and propionate levels decreased in Bangkok children in association with changes in their gut microbial communities. Stool samples of these Thai children were classified into five metabolotypes (MTs) based on their metabolome profiles, each characterized by high concentrations of short and middle chain fatty acids (MT1, n = 17), amino acids (MT2, n = 7), arginine (MT3, n = 6), amino acids, and amines (MT5, n = 8), or an overall low level of metabolites (MT4, n = 4). MT1 and MT4 mainly consisted of samples from Buriram, and MT2 and MT3 mainly consisted of samples from Bangkok, whereas MT5 contained three samples from Bangkok and five from Buriram samples. According to the profiles of microbiota and diets, MT1 and MT2 are characteristic of children in Buriram and Bangkok, respectively. Predicted metagenomics indicated the underrepresentation in MT2 of eight genes involved in pathways of butyrate biosynthesis, notably including paths from glutamate as well as pyruvate. Taken together, this study shows the benefit of high-vegetable Thai traditional diets on gut microbiota and suggests that high-fat and less-vegetable urban dietary habits alter gut microbial communities in Thai children, which resulted in the reduction of colonic short chain fatty acid fermentation.

Genetic diversity patterns of rice (Oryza sativa L.) landraces after migration by Tai Lue and Akha between China and Thailand

Cultivated rice (Oryza sativa L.) is genetically diverse, and the numerous landraces represent a valuable genetic resource for present and future rice breeding. Part of the genetic rice diversity is held by the ethnic minority groups of Tai Lue and Akha who migrated from southern China to northern Thailand over the past two centuries. We analysed variation in simple sequence repeats (SSR) and an indel in the ORF100 region in their rice germplasms in Thailand and in China to understand if the communities today in the Nan and Chang Rai provinces in Thailand still cultivate traditional rice landraces of the Xishungbanna region in southern China, and how such traditional germplasms have evolved in isolation after the human migrations. We found one multilocus genotype shared by all upland rice populations in China and Thailand and that several allelic combinations of the Thai populations can be traced to the alleles pools of upland and paddy rice of the Xishungbanna rice populations. However the frequent occurrence of hybrids between upland and paddy rice in the Thai and Chinese germplasms of both the ethnic communities reveal genetic erosion of the traditional landraces due to hybridization and introgression.