Critical analysis of protein signaling networks involved in the regulation of plant secondary metabolism: focus on anthocyanins

<p>Anthocyanin biosynthesis in <i>Arabidopsis</i> is a convenient and relatively simple model for investigating the basic principles of secondary metabolism regulation. In recent years, many publications have described links between anthocyanin biosynthesis and general defense reactions in plants as well as photomorphogenesis and hormonal signaling. These relationships are complex, and they cannot be understood intuitively. Upon observing the lacuna in the <i>Arabidopsis</i> interactome (an interaction map of the factors involved in the regulation of <i>Arabidopsis</i> secondary metabolism is not available), we attempted to connect various cellular processes that affect anthocyanin biosynthesis. In this review, we revealed the main signaling protein modules that regulate anthocyanin biosynthesis. To our knowledge, this is the first reconstruction of a network of proteins involved in plant secondary metabolism.</p

Green synthesis of silver nanoparticles using transgenic <i>Nicotiana tabacum</i> callus culture expressing silicatein gene from marine sponge <i>Latrunculia oparinae</i>

<p>In the present investigation, transgenic tobacco callus cultures and plants overexpressing the silicatein gene <i>LoSilA1</i> from marine sponge <i>Latrunculia oparinae</i> were obtained and their bioreduction behaviour for the synthesis of silver nanoparticles (AgNPs) was studied. Synthesized nanoparticles were characterized using UV–visible spectroscopy, Fourier transformed infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), atomic flame electron microscopy (AFM) and nanoparticle tracking analysis (NTA). Our measurements showed that the reduction of silver nitrate produced spherical AgNPs with diameters in the range of 12–80 nm. The results of XRD analysis proved the crystal nature of the obtained AgNPs. FTIR analysis indicated that particles are reduced and stabilized in solution by the capping agent, which is likely to be proteins present in the callus extract. Interestingly, the reduction potential of <i>LoSiLA1</i>-transgenic callus line was increased three-fold compared with the empty vector-transformed calli. The synthesized AgNPs were found to exhibit strong antibacterial activity against <i>Escherichia coli</i> and <i>Agrobacterium rhizogenes</i>. The present study reports the first evidence for using genetic engineering for activation of the reduction potential of plant cells for synthesis of biocidal AgNPs.</p