Enzymatic Characterization of Genes in and Overexpression of the .

Phenylalanine ammonia-lyase (PAL, EC 4.3.1.

Transcriptomic and physiological analysis of the response of Spirodela polyrrhiza to sodium nitroprusside.

Background: Spirodela polyrrhiza is a simple floating aquatic plant with great potential in synthetic biology. Sodium nitroprusside (SNP) stimulates plant development and increases the biomass and flavonoid content in some plants. However, the molecular mechanism of SNP action is still unclear.

Unveiling mechanisms of silicon-mediated resistance to chromium stress in rice using a newly-developed hierarchical system.

Silicon (Si) has been well-known to enhance plant resistance to heavy-metal stress. However, the mechanisms by which silicon mitigates heavy-metal stress in plants are not clear. In particular, information regarding the role of Si in mediating resistance to heavy-metal stress at a single cell level is still lacking.

Overexpression of the Phosphoserine Phosphatase-Encoding Gene () Promotes Starch Accumulation in 5511 under Sulfur Deficiency.

Duckweeds are well known for their high accumulation of starch under stress conditions, along with inhibited growth. The phosphorylation pathway of serine biosynthesis (PPSB) was reported as playing a vital role in linking the carbon, nitrogen, and sulfur metabolism in this plant. The overexpression of , the last key enzyme of the PPSB pathway in duckweed, was found to stimulate the accumulation of starch under sulfur-deficient conditions.

Over-Expression of Phosphoserine Aminotransferase-Encoding Gene () Prompts Starch Accumulation in under Nitrogen Starvation.

It has been demonstrated that the phosphorylation pathway of L-serine (Ser) biosynthesis (PPSB) is very important in plant growth and development, but whether and how PPSB affects nitrogen metabolism and starch accumulation has not been fully elucidated. In this study, we took the energy plant duckweed (strain 5511) as the research object and used a stable genetic transformation system to heterologously over-expressing Arabidopsis (the gene encoding phosphoserine aminotransferase, the second enzyme of PPSB). Our results showed that, under nitrogen starvation, the transgenic plants grew faster, with higher values of Fv/Fm, rETR, and Y(II), as well as fresh and dry weight, than the wild-type.

Molecular mechanism underlying the effect of maleic hydrazide treatment on starch accumulation in S. polyrrhiza 7498 fronds.

Background: Duckweed is considered a promising feedstock for bioethanol production due to its high biomass and starch production. The starch content can be promoted by plant growth regulators after the vegetative reproduction being inhibited. Maleic hydrazide (MH) has been reported to inhibit plant growth, meantime to increase biomass and starch content in some plants.

Declined cadmium accumulation in Na/H antiporter (NHX1) transgenic duckweed under cadmium stress.

Cadmium (Cd) is a serious threat to plants health. Though some genes have been reported to get involved in the regulation of tolerance to Cd, the mechanisms underlying this process are not fully understood. Na/H antiporter (NHX1) plays an important role in Na/H trafficking.

Overexpression of AtAGT1 promoted root growth and development during seedling establishment.

Arabidopsis photorespiratory gene AtAGT1 is important for the growth and development of root, the non-photosynthetic organ, and it is involved in a complex metabolic network and salt resistance. AtAGT1 in Arabidopsis encodes an aminotransferase that has a wide range of donor:acceptor combinations, including Asn:glyoxylate. Although it is one of the photorespiratory genes, its encoding protein has been suggested to function also in roots to metabolize Asn.

A transgene design for enhancing oil content in Arabidopsis and Camelina seeds.

Background: Increasing the oil yield is a major objective for oilseed crop improvement. Oil biosynthesis and accumulation are influenced by multiple genes involved in embryo and seed development. The () is a master regulator of embryo development that also enhances the expression of genes involved in fatty acid biosynthesis.

Overexpression of PSP1 enhances growth of transgenic Arabidopsis plants under ambient air conditions.

The importance of the phosphorylated pathway (PPSB) of L-serine (Ser) biosynthesis in plant growth and development has been demonstrated, but its specific role in leaves and interaction with photorespiration, the main leaf Ser biosynthetic pathway at daytime, are still unclear. To investigate whether changes in biosynthesis of Ser by the PPSB in leaves could have an impact on photorespiration and plant growth, we overexpressed PSP1, the last enzyme of this pathway, under control of the Cauliflower Mosaic Virus 35S promoter in Arabidopsis thaliana. Overexpressor plants grown in normal air displayed larger rosette diameter and leaf area as well as higher fresh and dry weight than the wild type.

Acetic acid-induced programmed cell death and release of volatile organic compounds in Chlamydomonas reinhardtii.

Acetic acid widely spreads in atmosphere, aquatic ecosystems containing residues and anoxic soil. It can inhibit aquatic plant germination and growth, and even cause programmed cell death (PCD) of yeast. In the present study, biochemical and physiological responses of the model unicellular green algae Chlamydomonas reinhardtii were examined after acetic acid stress.

Synthesis, herbicidal activities, and 3D-QSAR of 2-cyanoacrylates containing aromatic methylamine moieties.

A series of novel 2-cyanoacrylates containing different aromatic rings were synthesized, and their structures were characterized by (1)H NMR, elemental analysis, and single-crystal X-ray diffraction analysis. Their herbicidal activities against four weeds and inhibition of photosynthetic electron transport against isolated chloroplasts (the Hill reaction) were evaluated. Both in vivo and in vitro data showed that the compounds containing benzene, pyridine, and thiazole moieties gave higher activities than those containing pyrimidine, pyridazine, furan, and tetrahedronfuran moieties.

Damage of PS II during senescence of Spirodela polyrrhiza explants under long-day conditions and its prevention by 6-benzyladenine.

The chlorophyll a (Chl a) fluorescence technique was applied to investigate damage of PS II during senescence of excised half-fronds in Spirodela polyrrhiza P143. The green explants showed a typical Chl a fluorescence transient, OJIP. After cultivation of explants under long-day conditions for 8 days, all the J, I, and P steps disappeared, but a clear K band, an indication of senescence, was observed.