Expression of Genes Related to Plant Hormone Signal Transduction in Jerusalem Artichoke (Helianthus tuberosus L.) Seedlings under Salt Stress

Background: Jerusalem artichoke (Helianthus tuberosus L.) is moderately tolerant to salinity stress and has high economic value. The salt tolerance mechanisms of Jerusalem artichoke are still unclear. Especially in the early stage of Jerusalem artichoke exposure to salt stress, gene transcription is likely to undergo large changes. Previous studies have hinted at the importance of temporal expression analysis in plant transcriptome research. Elucidating these changes may be of great significance to understanding the salt tolerance mechanisms of it. Results: We obtained high-quality transcriptome from leaves and roots of Jerusalem artichoke exposed to salinity (300 mM NaCl) for 0 h (hour), 6 h, 12 h, 24 h, and 48 h, with 150 and 129 unigenes and 9023 DEGs (differentially expressed genes). The RNA-seq data were clustered into time-dependent groups (nine clusters each in leaves and roots); gene functions were distributed evenly among them. KEGG enrichment analysis showed the genes related to plant hormone signal transduction were enriched in almost all treatment comparisons. Under salt stress, genes belonging to PYL (abscisic acid receptor PYR/PYL family), PP2C (Type 2C protein phosphatases), GH3 (Gretchen Hagen3), ETR (ethylene receptor), EIN2/3 (ethylene-insensitive protein 2/3), JAZ (genes such as jasmonate ZIM-domain gene), and MYC2 (Transcription factor MYC2) had extremely similar expression patterns. The results of qRT-PCR of 12 randomly selected and function known genes confirmed the accuracy of RNA-seq. Conclusions: Under the influence of high salinity (300 mM) environment, Jerusalem artichoke suffer serious damage in a short period of time. Based on the expression of genes on the time scale, we found that the distribution of gene functions in time is relatively even. Upregulation of the phytohormone signal transduction had a crucial role in the response of Jerusalem artichoke seedlings to salt stress, and the genes of abscisic acid, auxin, ethylene, and jasmonic acid had the most obvious change pattern. Research emphasized the regulatory role of hormones under high salt shocks and provided an explorable direction for the study of plant salt tolerance mechanisms.

Anti-Inflammatory Effects of Heliangin from Jerusalem Artichoke (Helianthus tuberosus) Leaves Might Prevent Atherosclerosis

Atherosclerosis is considered the major cause of cardiovascular and cerebrovascular diseases, which are the leading causes of death worldwide. Excessive nitric oxide production and inflammation result in dysfunctional vascular endothelial cells, which are critically involved in the initiation and progression of atherosclerosis. The present study aimed to identify a bioactive compound from Jerusalem artichoke leaves with anti-inflammatory activity that might prevent atherosclerosis. We isolated bioactive heliangin that inhibited NO production in LPS-induced macrophage-like RAW 264.7 cells. Heliangin suppressed ICAM-1, VCAM-1, E-selectin, and MCP-1 expression, as well as NF-κB and IκBα phosphorylation, in vascular endothelial cells stimulated with TNF-α. These results suggested that heliangin suppresses inflammation by inhibiting excessive NO production in macrophages and the expression of the factors leading to the development of atherosclerosis via the NF-κB signaling pathway in vascular endothelial cells. Therefore, heliangin in Jerusalem artichoke leaves could function in the prevention of atherosclerosis that is associated with heart attacks and strokes.

Production and Properties of Microbial Polyhydroxyalkanoates Synthesized from Hydrolysates of Jerusalem Artichoke Tubers and Vegetative Biomass

One of the major challenges in PHA biotechnology is optimization of biotechnological processes of the entire synthesis, mainly by using new inexpensive carbon substrates. A promising substrate for PHA synthesis may be the sugars extracted from the Jerusalem artichoke. In the present study, hydrolysates of Jerusalem artichoke (JA) tubers and vegetative biomass were produced and used as carbon substrate for PHA synthesis. The hydrolysis procedure (the combination of aqueous extraction and acid hydrolysis, process temperature and duration) influenced the content of reducing substances (RS), monosaccharide contents, and the fructose/glucose ratio. All types of hydrolysates tested as substrates for cultivation of three strains—C. necator B-10646 and R. eutropha B 5786 and B 8562—were suitable for PHA synthesis, producing different biomass concentrations and polymer contents. The most productive process, conducted in 12-L fermenters, was achieved on hydrolysates of JA tubers (X = 66.9 g/L, 82% PHA) and vegetative biomass (55.1 g/L and 62% PHA) produced by aqueous extraction of sugars at 80 °C followed by acid hydrolysis at 60 °C, using the most productive strain, C. necator B-10646. The effects of JA hydrolysates on physicochemical properties of PHAs were studied for the first time. P(3HB) specimens synthesized from the JA hydrolysates, regardless of the source (tubers or vegetative biomass), hydrolysis conditions, and PHA producing strain employed, exhibited the 100–120 °C difference between the Tmelt and Tdegr, prevailing of the crystalline phase over the amorphous one (Cx between 69 and 75%), and variations in weight average molecular weight (409–480) kDa. Supplementation of the culture medium of C. necator B-10646 grown on JA hydrolysates with potassium valerate and ε-caprolactone resulted in the synthesis of P(3HB-co-3HV) and P(3HB-co-4HB) copolymers that had decreased degrees of crystallinity and molecular weights, which influenced the porosity and surface roughness of polymer films prepared from them. The study shows that JA hydrolysates used as carbon source enabled productive synthesis of PHAs, comparable to synthesis from pure sugars. The next step is to scale up PHA synthesis from JA hydrolysates and conduct the feasibility study. The present study contributes to the solution of the critical problem of PHA biotechnology—finding widely available and inexpensive substrates.

Jerusalem Artichoke as a Fodder Crop for Food Security Solutions

Being a valuable source of inulin, fructose and pectin, Jerusalem artichoke (Helianthus tuberosus L.) is one of the most promising bioenergy crops for common usage. Animals have been reported to eat both Jerusalem artichoke green mass and tubers with pleasure. On the one hand, Jerusalem artichoke is cultivated on the area of about 3 thousand hectares in Russia. On the other hand, there are more than 200 crop species. So it is critical to choose a proper variety suitable both for soil and climatic conditions. The purpose of the research is to study Jerusalem artichoke, taking into account varietal characteristics appropriate for forage production. Research objects – varieties of Jerusalem artichoke: early ripening Skorospelka (RF); mid-early Vylgortskiy (RF); mid-season Dieticheskiy (RF), Kaluzhskiy (RF), Korenevskiy (RF), Nadezhda (RF), Nakhodka (RF), Podmoskovniy (RF), Sireniki (RB), Blank Brekos (France), Violet de Rense (France); late ripening Interest (RF), Interest 21 (RF), Novosti VIRa (RF), Tadzhikskiy Krasniy (USSR), Spindle (Germany). The soil for evaluating Jerusalem artichoke varieties was from experimental plot base "Korenevo". It is characterized as sod-slightly podzolic sandy loam. The field trial was established and the records and observations were carried out in accordance with the requirements of the field experiment methodology (1985), and the Program and methodology for evaluating Jerusalem artichoke varieties in test nurseries (2014). The varieties Vylgortskiy, Dieticheskiy, Nadezhda, Nakhodka, Sireniki, Skorospelka, Blank Brekos and Kaluzhskiy were found to reach due height of 155 - 170 cm at the end of the growing season; the varieties Podmoskovniy, Interest reached proper height of 175 - 208 cm; the varieties Interest 21, Tadzhikskiy and Violet de Rense were about 220 - 235 cm in hight; as for the varieties Korenevskiy, Novost VIRa, Spindlу their hight was 270 - 280 cm. According to aggregate amount of feed units per 1 ha, the following varieties have been shown to be the most reasonable for fodder production: Novost VIRa (22,438 fodder units), Nadezhda (19,928 fodder units), Korenevskiy (17,798 fodder units), Shpindle (16,887 fodder units), Dieticheskiy (16,395 fodder units), and Interest (16,116 fodder units). The highest total coefficient of energy efficiency has been found in the following varieties: Novost VIRa – 3.09, Tadzhikskiy – 2.78; Spindle – 2.68; Korenevskiy – 2.43; Interest – 2.10; Skorospelka – 1.98. The results of experimental and theoretical studies obtained were verified on-the-farm conditions based on a seed-speciality farm LLC Kaluga-Agro (the Kaluga region) and demonstrated beneficial effect.