Expression of the human UDP-galactose transporter gene hUGT1 in tobacco plants' enhanced plant hardness

FLS2-RBOHD module regulates changes in the metabolome of Arabidopsis in response to abiotic stress

Through crosstalk, FLAGELLIN SENSITIVE 2 (FLS2) and RESPIRATORY BURST OXIDASE HOMOLOG D (RBOHD) are involved in regulating the homeostasis of cellular reactive oxygen species (ROS) and are linked to the metabolic response of plants toward both biotic and abiotic stress. In the present study, we examined the metabolome of Arabidopsis seedlings under drought and salt conditions to better understand the potential role of FLS2 and RBOHD-dependent signaling in the regulation of abiotic stress response. We identified common metabolites and genes that are regulated by FLS2 and RBOHD, and are involved in the response to drought and salt stress. Under drought conditions, D-aspartic acid and the expression of associated genes, such as ASPARAGINE SYNTHASE 2 (ASN2), increased in both fls2 and robed/f double mutants. The accumulation of amino acids, carbohydrates, and hormones, such as L-proline, D-ribose, and indoleacetaldehyde increased in both fls2 and rbohd/f double mutants under salt conditions, as did the expression of related genes, such as PROLINE IMINOPEPTIDASE, PHOSPHORIBOSYL PYROPHOSPHATE SYNTHASE 5, and NITRILASE 3. Collectively, these results indicate that the FLS2-RBOHD module regulates plant response to drought and salt stress through ROS signaling by adjusting the accumulation of metabolites and expression of genes related to metabolite synthesis.

Mapping Resistance to Argentinean Fusarium (Graminearum) Head Blight Isolates in Wheat

Fusarium head blight (FHB) of wheat, caused by Fusarium graminearum (Schwabe), is a destructive disease worldwide, reducing wheat yield and quality. To accelerate the improvement of scab tolerance in wheat, we assessed the International Triticeae Mapping Initiative mapping population (ITMI/MP) for Type I and II resistance against a wide population of Argentinean isolates of F. graminearum. We discovered a total of 27 additive QTLs on ten different (2A, 2D, 3B, 3D, 4B, 4D, 5A, 5B, 5D and 6D) wheat chromosomes for Type I and Type II resistances explaining a maximum of 15.99% variation. Another four and two QTLs for thousand kernel weight in control and for Type II resistance, respectively, involved five different chromosomes (1B, 2D, 6A, 6D and 7D). Furthermore, three, three and five QTLs for kernel weight per spike in control, for Type I resistance and for Type II resistance, correspondingly, involved ten chromosomes (2A, 2D, 3B, 4A, 5A, 5B, 6B, 7A, 7B, 7D). We were also able to detect five and two epistasis pairs of QTLs for Type I and Type II resistance, respectively, in addition to additive QTLs that evidenced that FHB resistance in wheat is controlled by a complex network of additive and epistasis QTLs.

Changes of lignin biosynthesis in tobacco leaves during maturation

Lignin is one of the most valuable renewable industrial materials. To elucidate the mechanism via which lignin is synthesised, we compared the lignin content, leaf hardness, cell wall thickness of palisade tissue, and gene expression patterns of lignin biosynthetic enzymes in three tobacco (Nicotiana tabacum L.) varieties during maturation. The results consistently showed that during maturation, the accumulation of lignin gradually increased in tobacco leaves, reaching a peak at full maturity (45 days after topping), and then gradually decreased. Similarly, the transcript level analysis revealed that the gene expression pattern of NtPAL, NtC4H, NtCCoAOMT and NtCOMT were relatively high, and consistent with the lignin content changes. Thus, the four genes may play regulatory roles in the synthesis of tobacco lignin. Analysis of tissue expression patterns of the lignin synthesis-related gene showed that the NtPAL, NtC4H, Nt4CL, NtHCT, NtCCoAOMT, NtCOMT, NtCCR, NtCAD, and NtPAO were all expressed in stems, roots, and leaves. NtC3H and NtF5H were specifically expressed in stems and roots, and not in leaves. Consistently, the NtC3H promoter induced high GUS expression in stems and petioles, marginal in roots, and no GUS activity in leaves. These results provide insights into molecular regulation of lignin biosynthesis in tobacco.

Biomass utilization and production of biofuels from carbon neutral materials

The availability of organic matters in vast quantities from the agricultural/industrial practices has long been a significant environmental challenge. These wastes have created global issues in increasing the levels of BOD or COD in water as well as in soil or air segments. Such wastes can be converted into bioenergy using a specific conversion platform in conjunction with the appropriate utilization of the methods such as anaerobic digestion, secondary waste treatment, or efficient hydrolytic breakdown as these can promote bioenergy production to mitigate the environmental issues. By the proper utilization of waste organics and by adopting innovative approaches, one can develop bioenergy processes to meet the energy needs of the society. Waste organic matters from plant origins or other agro-sources, biopolymers, or complex organic matters (cellulose, hemicelluloses, non-consumable starches or proteins) can be used as cheap raw carbon resources to produce biofuels or biogases to fulfill the ever increasing energy demands. Attempts have been made for bioenergy production by biosynthesizing, methanol, n-butanol, ethanol, algal biodiesel, and biohydrogen using different types of organic matters via biotechnological/chemical routes to meet the world's energy need by producing least amount of toxic gases (reduction up to 20-70% in concentration) in order to promote sustainable green environmental growth. This review emphasizes on the nature of available wastes, different strategies for its breakdown or hydrolysis, efficient microbial systems. Some representative examples of biomasses source that are used for bioenergy production by providing critical information are discussed. Furthermore, bioenergy production from the plant-based organic matters and environmental issues are also discussed. Advanced biofuels from the organic matters are discussed with efficient microbial and chemical processes for the promotion of biofuel production from the utilization of plant biomasses.

Expression of a fungal exo-β-1,3-galactanase in Arabidopsis reveals a role of type II arabinogalactans in the regulation of cell shape

Arabinogalactan-proteins (AGPs) are a family of plant extracellular proteoglycans implicated in many physiological events. AGP is decorated with type II arabinogalactans (AGs) consisting of a β-1,3-galactan backbone and β-1,6-galactan side chains, to which other sugars are attached. Based on the fact that a type II AG-specific inhibitor, β-Yariv reagent, perturbs growth and development, it has been proposed that type II AGs participate in the regulation of cell shape and tissue organization. However, the mechanisms by which type II AGs participate have not yet been established. Here, we describe a novel system that causes specific degradation of type II AGs in Arabidopsis, by which a gene encoding a fungal exo-β-1,3-galactanase that specifically hydrolyzes β-1,3-galactan backbones of type II AGs is expressed under the control of a dexamethasone-inducible promoter. Dexamethasone treatment increased the galactanase activity, leading to a decrease in Yariv reagent-reactive AGPs in transgenic Arabidopsis. We detected the typical oligosaccharides released from type II AGs by Il3GAL in the soluble fraction, demonstrating that Il3GAL acted on type II AG in the transgenic plants. Additionally, this resulted in severe tissue disorganization in the hypocotyl and cotyledons, suggesting that the degradation of type II AGs affected the regulation of cell shape.