This cover illustrates the concept of synthetic biology and bioproduction in plants. Plants absorb CO₂ and, through the introduction of gene circuits from other organisms or artificially generated, can produce a variety of products, including pharmaceuticals, fine chemicals, raw materials for bioplastics, biofuels, and more.
The concepts of gene editing, metabolic pathway shifting, gene network manipulation, and the DBTL (Design-Build-Test-Learn) cycle are crucial for the implementation of synthetic biology and bioproduction in plants. The goal of synthetic biology and bioproduction in plants is to contribute to carbon recycling, which is a central component of the bioeconomy. Chemical structures of lignin, acteoside, menthol, corosolic acid, and isoprene are described clockwise from left top.

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The anthocyanin related glutathione S-transferase (GST) belongs to the Phi class of the GST family and has been regarded to play a role in anthocyanin transport to the vacuole. We isolated its orthologue from the torenia petal. Transgenic plants transcribing GST double stranded RNA were generated from a blue torenia. Resultant plants exhibited a range of flower colors, from blue to almost white. However, pure white flowers were not obtained in site of significant downregulation of the GST transcript. Anthocyanin levels in the petals of the transgenic plants decreased, whereas flavone levels remained unchanged. Anthocyanins and flavones may be transported to the vacuole through different mechanisms (Akagi et al, pp. 147–151) .

AtGTLP is a novel trans-Golgi-localized Arabidopsis protein with characteristics of a glycosyltransferase. The micrograph shows root cells after double visualization of Arabidopsis line co-expressing AtGTLP-mGFP and a mRFP-tagged trans-Golgi marker, ST. Subcellular localization was observed using Zeiss LSM980 confocal laser scanning microscope system equipped with Plan-Apochromat 63x/1.40 Oil DIC M27 immersion objective. Adapted from: Rzepecka et al. (pp. 35–44).

Plant cell wall plays important roles in the regulation of plant growth/development and affects the quality of plant-derived foods. Genetic variability of cell wall components within a plant species, however, has not been well understood. In this issue, Zamorski et al. showed that the endosperm cell walls from 89 rice varieties were clearly classified into two groups, depending on the presence/absence of β-1,4-linked glucomannan (See Zamorski et al, pp. 321–336). Immunoelectron microscopic observation of developing rice grains with an anti-Man4 antibody often detected the accumulation of glucomannan (indicated by the presence of gold particles) in the middle portion of the thick aleurone cell walls of a glucomannan-positive variety, Fujisaka-5, suggesting that the glucomannan was synthesized in the early stage of endosperm development but the synthesis was downregulated during the secondary thickening process associated with the differentiation of aleurone layer.