Examining the physiological and genetic response of maize to low temperature conditions

peer-reviewedMaize (Zea mays) is an emerging forage crop in Ireland, originating in warmer climates. Under Irish climate conditions establishment can be problematic due to low soil temperatures at early stages of establishment. Maize varieties with improved chilling tolerance have been developed and are on the market, but maize in Ireland is still established under plastic and further varietal improvements are required to make this crop more economically viable. To date, varieties are selected principally by phenotypic traits rather than genetic response. Investigation of the physiological and genetic response of maize towards cold/chilling stress at early developmental stage, in particular the response of developing maize roots to cold stress, can make a contribution towards the understanding of the molecular mechanisms conferring plant cold tolerance. The objectives of this study were aimed to create, at first, an experimental design to test the physiological response to low temperatures, under controlled environmental conditions, of various commercial maize cultivars adapted to grow in temperate climates. Responses to abiotic stresses such as cold involve changes in gene expression, therefore, once indentified the hybrids showing contrasting degrees of cold tolerance, these were profilied to examine gene expression and identify possible cold regulated genes. The physiological experiments on twelve maize varieties identified four genotypes with contrasting cold tolerance. Microarray analysis profiling these varieties was used to identify up and down regulated genes under cold/chilling conditions. The stress induced by the cold temperature in the genotypes Picker, PR39B29, Fergus and Codisco was reflected only on the expression profiles of the two varieties with superior cold tolerance, Picker and PR39B29. No significant changes in expression were observed in Fergus and Codisco in response to cold stress. The overall number of genes up and down regulated in the two cold tolerant varieties amounted to 69, which were, however, divided in a group of 39 genes in PR39B29 and 30 genes in Picker, as the two varieties exhibited two different trancriptomic patterns in which only four genes (RNA binding protein, pathogenesis-related protein 1 and two unknown proteins) were shared, although not all with the same degree of regulation. No cold regulated genes ware detected. The gene expression of the four-shared genes was further investigated with qRT-PCR in order to estimate the expression pattern over time. Five time points were used to analyse the expression trend of the genes. The gene expression was not maintained over the five time points, but it was subjected to fluctuation. However, with the exception of the RNA binding protein gene, the expression pattern was similar between the two varieties, indicating a common response to chilling stress

Transcriptomic response of maize primary roots to low temperatures at seedling emergence

peer-reviewedBackground Maize (Zea mays) is a C4 tropical cereal and its adaptation to temperate climates can be problematic due to low soil temperatures at early stages of establishment. Methods In the current study we have firstly investigated the physiological response of twelve maize varieties, from a chilling condition adapted gene pool, to sub-optimal growth temperature during seedling emergence. To identify transcriptomic markers of cold tolerance in already adapted maize genotypes, temperature conditions were set below the optimal growth range in both control and low temperature groups. The conditions were as follows; control (18 °C for 16 h and 12 °C for 8 h) and low temperature (12 °C for 16 h and 6 °C for 8 h). Four genotypes were identified from the condition adapted gene pool with significant contrasting chilling tolerance. Results Picker and PR39B29 were the more cold-tolerant lines and Fergus and Codisco were the less cold-tolerant lines. These four varieties were subjected to microarray analysis to identify differentially expressed genes under chilling conditions. Exposure to low temperature during establishment in the maize varieties Picker, PR39B29, Fergus and Codisco, was reflected at the transcriptomic level in the varieties Picker and PR39B29. No significant changes in expression were observed in Fergus and Codisco following chilling stress. A total number of 64 genes were differentially expressed in the two chilling tolerant varieties. These two varieties exhibited contrasting transcriptomic profiles, in which only four genes overlapped. Discussion We observed that maize varieties possessing an enhanced root growth ratio under low temperature were more tolerant, which could be an early and inexpensive measure for germplasm screening under controlled conditions. We have identified novel cold inducible genes in an already adapted maize breeding gene pool. This illustrates that further varietal selection for enhanced chilling tolerance is possible in an already preselected gene pool

GCN5-dependent acetylation of HIV-1 integrase enhances viral integration

<p>Abstract</p> <p>Background</p> <p>An essential event during the replication cycle of HIV-1 is the integration of the reverse transcribed viral DNA into the host cellular genome. Our former report revealed that HIV-1 integrase (IN), the enzyme that catalyzes the integration reaction, is positively regulated by acetylation mediated by the histone acetyltransferase (HAT) p300.</p> <p>Results</p> <p>In this study we demonstrate that another cellular HAT, GCN5, acetylates IN leading to enhanced 3'-end processing and strand transfer activities. GCN5 participates in the integration step of HIV-1 replication cycle as demonstrated by the reduced infectivity, due to inefficient provirus formation, in GCN5 knockdown cells. Within the C-terminal domain of IN, four lysines (K258, K264, K266, and K273) are targeted by GCN5 acetylation, three of which (K264, K266, and K273) are also modified by p300. Replication analysis of HIV-1 clones carrying substitutions at the IN lysines acetylated by both GCN5 and p300, or exclusively by GCN5, demonstrated that these residues are required for efficient viral integration. In addition, a comparative analysis of the replication efficiencies of the IN triple- and quadruple-mutant viruses revealed that even though the lysines targeted by both GCN5 and p300 are required for efficient virus integration, the residue exclusively modified by GCN5 (K258) does not affect this process.</p> <p>Conclusions</p> <p>The results presented here further demonstrate the relevance of IN post-translational modification by acetylation, which results from the catalytic activities of multiple HATs during the viral replication cycle. Finally, this study contributes to clarifying the recent debate raised on the role of IN acetylated lysines during HIV-1 infection.</p

Industrial biotechnology is an advanced technology at the heart of the bioeconomy and the circular economy: its development needs efforts from the public sector

• Breakthroughs in engineering biology, such as synthetic biology, are impulsing new developments in industrial biotechnology andprovide low carbon solutions for societal challenges.• Industrial Biotechnology is relevant to the bioeconomy and the circular economy because it provides solutions to valorise biobasedresources, including organic residues and waste streams.• The combination of biobased and digital technologies is generating new opportunities to develop advanced manufacturingprocesses, products and services.• The EU must increase its investments in biotechnology to acquire greater manufacturing autonomy taking back control over strategicvalue chain.• Tomorrow's industrial biotechnology will contribute significantly to efforts to achieve the aims of the Green Deal and those of UNSustainable Development Goal

Antiviral Activity and Conformational Features of an Octapeptide Derived from the Membrane-Proximal Ectodomain of the Feline Immunodeficiency Virus Transmembrane Glycoprotein

Feline immunodeficiency virus (FIV) provides a valuable animal model by which criteria for lentivirus control strategies can be tested. Previous studies have shown that a 20-mer synthetic peptide of the membrane-proximal ectodomain of FIV transmembrane glycoprotein, designated peptide 59, potently inhibited the growth of tissue culture-adapted FIV in feline fibroblastoid CrFK cells. In the present report we describe the potential of this peptide to inhibit the replication of primary FIV isolates in lymphoid cells. Because antiviral activity of peptide 59 was found to map to a short segment containing three conserved Trp residues, further analyses focused on a derivative of eight amino acids ((770)W-I(777)), designated C8. Peptide C8 activity was found to be dependent on conservation of the Trp motif, to be removed from solution by FIV absorbed onto substrate cells, and to be blocked by a peptide derived from the N-terminal portion of FIV transmembrane glycoprotein. Structural studies showed that peptide C8 possesses a conformational propensity highly uncommon for peptides of its size, which may account for its considerable antiviral potency in spite of small size

Xyloglucan Oligosaccharides Hydrolysis by Exo-Acting Glycoside Hydrolases from Hyperthermophilic Microorganism Saccharolobus solfataricus

In the field of biocatalysis and the development of a bio-based economy, hemicellulases have attracted great interest for various applications in industrial processes. However, the study of the catalytic activity of the lignocellulose-degrading enzymes needs to be improved to achieve the efficient hydrolysis of plant biomasses. In this framework, hemicellulases from hyperthermophilic archaea show interesting features as biocatalysts and provide many advantages in industrial applications thanks to their stability in the harsh conditions encountered during the pretreatment process. However, the hemicellulases from archaea are less studied compared to their bacterial counterpart, and the activity of most of them has been barely tested on natural substrates. Here, we investigated the hydrolysis of xyloglucan oligosaccharides from two different plants by using, both synergistically and individually, three glycoside hydrolases from Saccharolobus solfataricus: a GH1 β-gluco-/β-galactosidase, a α-fucosidase belonging to GH29, and a α-xylosidase from GH31. The results showed that the three enzymes were able to release monosaccharides from xyloglucan oligosaccharides after incubation at 65 °C. The concerted actions of β-gluco-/β-galactosidase and the α-xylosidase on both xyloglucan oligosaccharides have been observed, while the α-fucosidase was capable of releasing all α-linked fucose units from xyloglucan from apple pomace, representing the first GH29 enzyme belonging to subfamily A that is active on xyloglucan