Post-doctoral researcher, Academia Sinica
Soybean is the most important crop in the world with a production in 2015 of about 319 million tons of beans. Soybean is also very important for agriculture in the United States because more than 30% of worldwide soybean beans were produced in America. Soybean seed contains high nutritional values and is rich in proteins (with 6-7 fold higher than that of rice and wheat), lipids and carbohydrates which serve as a major source of food for humans. Soybean seed is used to make various foods, such as tofu, soymilk, and soy source. Recently, soybean seed also severs as a promising resource for biofuel due to high lipid content. In the near future, human being will face the challenge of food security and energy crisis because of population explosion. We will need to produce ~70 to 100% more food by 2050. Increased yield may be achieved through modification in developmental traits, e.g., increases in the size, number, and more importantly, nutritional quality of seeds. The aim of my research is to uncover the molecular regulatory mechanism of soybean seed development and help scientists to breed soybean with higher nutritional quality seeds. A complex gene-regulatory networks are involved in soybean seed development. In order to study soybean seed development, various genetic and molecular methods were used in my research. So far, several critical factors (transcription factors) had been identified as the key regulators for biosynthesis of lipids and storage proteins in soybean seed. These factors can be used as genetic and molecular markers for soybean breeding and modification and eventually increase the nutritional value of soybean seeds.
Abstract: FUSCA3 (FUS3) is a B3 domain transcription factor that is a member of the LEAFY COTYLEDON (LEC) group of genes. The LEC genes encode proteins that also include LEC2, a B3 domain factor related to FUS3, and LEC1, a CCAAT box-binding factor. LEC1, LEC2, and FUS3 are essential for plant embryo development. All three loss-of-function mutants in Arabidopsis (Arabidopsis thaliana) prematurely exit embryogenesis and enter seedling developmental programs. When ectopically expressed, these genes promote embryo programs in seedlings. We report on chromatin immunoprecipitation-tiling array experiments to globally map binding sites for FUS3 that, along with other published work to assess transcriptomes in response to FUS3, allow us to determine direct from indirect targets. Many transcription factors associated with embryogenesis are direct targets of FUS3, as are genes involved in the seed maturation program. FUS3 regulates genes encoding microRNAs that, in turn, control transcripts encoding transcription factors involved in developmental phase changes. Examination of direct targets of FUS3 reveals that FUS3 acts primarily or exclusively as a transcriptional activator. Regulation of microRNA-encoding genes is one mechanism by which FUS3 may repress indirect target genes. FUS3 also directly up-regulates VP1/ABI3-LIKE1 (VAL1), encoding a B3 domain protein that functions as a repressor of transcription. VAL1, along with VAL2 and VAL3, is involved in the transition from embryo to seedling development. Many genes are responsive to FUS3 and to VAL1/VAL2 but with opposite regulatory consequences. The emerging picture is one of complex cross talk and interactions among embryo transcription factors and their target genes.
Pub.: 15 Jan '13, Pinned: 30 Sep '17
Abstract: The transcription factor LEAFY COTYLEDON1 (LEC1) controls aspects of early embryogenesis and seed maturation in Arabidopsis thaliana. To identify components of the LEC1 regulon, transgenic plants were derived in which LEC1 expression was inducible by dexamethasone treatment. The cotyledon-like leaves and swollen root tips developed by these plants contained seed-storage compounds and resemble the phenotypes produced by increased auxin levels. In agreement with this, LEC1 was found to mediate up-regulation of the auxin synthesis gene YUCCA10. Auxin accumulated primarily in the elongation zone at the root-hypocotyl junction (collet). This accumulation correlates with hypocotyl growth, which is either inhibited in LEC1-induced embryonic seedlings or stimulated in the LEC1-induced long-hypocotyl phenotype, therefore resembling etiolated seedlings. Chromatin immunoprecipitation analysis revealed a number of phytohormone- and elongation-related genes among the putative LEC1 target genes. LEC1 appears to be an integrator of various regulatory events, involving the transcription factor itself as well as light and hormone signalling, especially during somatic and early zygotic embryogenesis. Furthermore, the data suggest non-embryonic functions for LEC1 during post-germinative etiolation.
Pub.: 21 Mar '12, Pinned: 30 Sep '17
Abstract: The plant-specific, B3 domain-containing transcription factor ABSCISIC ACID INSENSITIVE3 (ABI3) is an essential component of the regulatory network controlling the development and maturation of the Arabidopsis thaliana seed. Genome-wide chromatin immunoprecipitation (ChIP-chip), transcriptome analysis, quantitative reverse transcriptase-polymerase chain reaction and a transient promoter activation assay have been combined to identify a set of 98 ABI3 target genes. Most of these presumptive ABI3 targets require the presence of abscisic acid for their activation and are specifically expressed during seed maturation. ABI3 target promoters are enriched for G-box-like and RY-like elements. The general occurrence of these cis motifs in non-ABI3 target promoters suggests the existence of as yet unidentified regulatory signals, some of which may be associated with epigenetic control. Several members of the ABI3 regulon are also regulated by other transcription factors, including the seed-specific, B3 domain-containing FUS3 and LEC2. The data strengthen and extend the notion that ABI3 is essential for the protection of embryonic structures from desiccation and raise pertinent questions regarding the specificity of promoter recognition.
Pub.: 26 Jun '12, Pinned: 30 Sep '17
Abstract: Seeds play an integral role in the global food supply and account for more than 70% of the calories that we consume on a daily basis. To meet the demands of an increasing population, scientists are turning to seed genomics research to find new and innovative ways to increase food production. Seed genomics is evolving rapidly, and the information produced from seed genomics research has exploded over the past two decades. Advances in modern sequencing strategies that profile every molecule in every cell, tissue, and organ and the emergence of new model systems have provided the tools necessary to unravel many of the biological processes underlying seed development. Despite these advances, the analyses and mining of existing seed genomics data remain a monumental task for plant biologists. This review summarizes seed region and subregion genomic data that are currently available for existing and emerging oilseed models. We provide insight into the development of tools on how to analyze large-scale datasets.
Pub.: 14 Oct '14, Pinned: 30 Sep '17
Abstract: Seeds are complex structures that consist of the embryo, endosperm, and seed-coat regions that are of different ontogenetic origins, and each region can be further divided into morphologically distinct subregions. Despite the importance of seeds for food, fiber, and fuel globally, little is known of the cellular processes that characterize each subregion or how these processes are integrated to permit the coordinated development of the seed. We profiled gene activity genome-wide in every organ, tissue, and cell type of Arabidopsis seeds from fertilization through maturity. The resulting mRNA datasets offer the most comprehensive description of gene activity in seeds with high spatial and temporal resolution,providing unique insights into the function of understudied seed regions. Global comparisons of mRNA populations reveal unexpected overlaps in the functional identities of seed subregions. Analyses of coexpressed gene sets suggest that processes that regulate seed size and filling are coordinated across several subregions. Predictions of gene regulatory networks based on the association of transcription factors with enriched DNA sequence motifs upstream of coexpressed genes identify regulators of seed development. These studies emphasize the utility of these data sets as an essential resource for the study of seed biology.
Pub.: 16 Jan '13, Pinned: 30 Sep '17
Abstract: LEAFY COTYLEDON1 (LEC1), an atypical subunit of the nuclear transcription factor Y (NF-Y) CCAAT-binding transcription factor, is a central regulator that controls many aspects of seed development including the maturation phase during which seeds accumulate storage macromolecules and embryos acquire the ability to withstand desiccation. To define the gene networks and developmental processes controlled by LEC1, genes regulated directly by and downstream of LEC1 were identified. We compared the mRNA profiles of wild-type and lec1-null mutant seeds at several stages of development to define genes that are down-regulated or up-regulated by the lec1 mutation. We used ChIP and differential gene-expression analyses in Arabidopsis seedlings overexpressing LEC1 and in developing Arabidopsis and soybean seeds to identify globally the target genes that are transcriptionally regulated by LEC1 in planta Collectively, our results show that LEC1 controls distinct gene sets at different developmental stages, including those that mediate the temporal transition between photosynthesis and chloroplast biogenesis early in seed development and seed maturation late in development. Analyses of enriched DNA sequence motifs that may act as cis-regulatory elements in the promoters of LEC1 target genes suggest that LEC1 may interact with other transcription factors to regulate distinct gene sets at different stages of seed development. Moreover, our results demonstrate strong conservation in the developmental processes and gene networks regulated by LEC1 in two dicotyledonous plants that diverged ∼92 Mya.
Pub.: 26 Jul '17, Pinned: 30 Sep '17
Abstract: Crude seed coat extracts from Abrus precatorius and Caesalpinia crista were purified into four different fractions namely phenolic acids, flavonols, flavanols and anthocyanin which were then examined for their polyphenol contents and antimicrobial potentials. The fractions derived from seed coat of A. precatorius were found more potent with high phenolic and flavonoid contents as compared to C. crista fractions. The significant antibacterial activity was observed against all strain tested by the fractions of both samples apart from anthocyanin fraction. It was interesting to note that the phenolic acid fractions of both samples was found more active against gram-negative bacteria, while gram-positive bacteria were found to be more sensitive towards flavonol fractions. The phenolic acid and flavonol fractions being potent antibacterial were selected to demonstrate the antifungal capacity of two samples. Among them, phenolic acid fraction of both samples was found active towards all the fungal strain.
Pub.: 28 Sep '17, Pinned: 30 Sep '17
Abstract: •In urban area the most widely used method for ragweed control was improved.•Ideal timing and mowing height significantly reduced seed and pollen production in Ambrosia artemisiifoila.•The assessment method of pollen production is unique, reproducible and based on season long collection of pollen grains.•Optimal mowing dates are: first mowing before flowering of the terminal racemes (BBCH 59), second when re-sprouting terminal racemes reach (BBCH 59).•1–3 cm is the optimum cutting height.
Pub.: 01 May '17, Pinned: 30 Sep '17
Abstract: •Safe and controllable process was employed to coat fatty acids on the Fe3O4 NP.•Saponification reaction using solvent with natural source was used.•New hybrid algorithm called SA-LOOCV-GRBF was used to optimize process conditions.•Average diameter of NPs was 20 nm with a thickness of 5 nm for fatty acid coating.
Pub.: 01 Sep '17, Pinned: 30 Sep '17
Abstract: Skp1-Cullin-F-box (SCF) E3 ligases are essential to post-translational protein turnover and important to regulation in various developmental and environmental response pathways. The non-seed plant Physcomitrella patens is a powerful tool for functional genomics and provides insights into the evolution of plant gene structures and functions. Here we investigated SKP1-like (PpSKP) and F-box (PpFBX) gene families in Physcomitrella patens.
Pub.: 01 Dec '17, Pinned: 30 Sep '17