Identifying and Testing Dieback-Tolerant ASH (Fraxinus Excelsior) on Gotland Island, Baltic Sea, Sweden

В статье рассмотрены полевые исследования ясеня (Ffraxinus Excelsior) толерантного к усыханию от гриба Hymenoscyphus fraxineus на острове Готланд, Балтийское море, Швеция

Identification of Norway spruce MYB-bHLH-WDR transcription factor complex members linked to regulation of the flavonoid pathway

Transcription factors (TFs) forming MYB-bHLH-WDR complexes are known to regulate the biosynthesis of specialized metabolites in angiosperms through an intricate network. These specialized metabolites participate in a wide range of biological processes including plant growth, development, reproduction as well as in plant immunity. Studying the regulation of their biosynthesis is thus essential. While MYB (TFs) have been previously shown to control specialized metabolism (SM) in gymnosperms, the identity of their partners, in particular bHLH or WDR members, has not yet been revealed. To gain knowledge about MYB-bHLH-WDR transcription factor complexes in gymnosperms and their regulation of SW, we identified two bHLH homologs of AtTT8, six homologs of the MYB transcription factor AtTT2 and one WDR ortholog of AtTTG1 in Norway spruce. We investigated the expression levels of these genes in diverse tissues and upon treatments with various stimuli including methyl-salicylate, methyl-jasmonate, wounding or fungal inoculation. In addition, we also identified protein-protein interactions among different homologs of MYB, bHLH and WDR. Finally, we generated transgenic spruce cell lines overexpressing four of the Norway spruce AtTT2 homologs and observed differential regulation of genes in the flavonoid pathway and flavonoid contents.The Swedish Research Council Formas grant No. 2012–1276 and the Swedish Foundation for Strategic Research (SSF) grant No. R8b08-0011. This work was also supported by the National Science Foundation (IOS-1557796) to SM.http://www.frontiersin.orgam2017Forestry and Agricultural Biotechnology Institute (FABI)Microbiology and Plant Patholog

Identification of Norway Spruce MYB-bHLH-WDR Transcription Factor Complex Members Linked to Regulation of the Flavonoid Pathway

Transcription factors (TFs) forming MYB-bHLH-WDR complexes are known to regulate the biosynthesis of specialized metabolites in angiosperms through an intricate network. These specialized metabolites participate in a wide range of biological processes including plant growth, development, reproduction as well as in plant immunity. Studying the regulation of their biosynthesis is thus essential. While MYB (TFs) have been previously shown to control specialized metabolism (SM) in gymnosperms, the identity of their partners, in particular bHLH or WDR members, has not yet been revealed. To gain knowledge about MYB-bHLH-WDR transcription factor complexes in gymnosperms and their regulation of SW, we identified two bHLH homologs of AtTT8, six homologs of the MYB transcription factor AtTT2 and one WDR ortholog of AtTTG1 in Norway spruce. We investigated the expression levels of these genes in diverse tissues and upon treatments with various stimuli including methyl-salicylate, methyl-jasmonate, wounding or fungal inoculation. In addition, we also identified protein-protein interactions among different homologs of MYB, bHLH and WDR. Finally, we generated transgenic spruce cell lines overexpressing four of the Norway spruce AtTT2 homologs and observed differential regulation of genes in the flavonoid pathway and flavonoid contents

Forest damage

Heterobasidion root and butt rot pose a greater risk in continuous cover forestry (CCF) than in rotation forestry (RF) in conifer-dominated forests, regardless of whether selective, gap or shelterwood cutting is used. Damage from wind, snow, spruce bark beetle, and large pine weevil are likely to be less severe in CCF than in RF. However, the conversion of RF to CCF may briefly expose stands to windthrow. Browsing by large herbivores on saplings may limit regeneration of tree species other than spruce in continuous cover forestry and reduce tree species diversity, but alternative silvicultural practices may also increase forage availability in the field and shrub layer. Browsing damage outcomes for saplings in CCF are difficult to predict. For many types of damage in CCF, substantial knowledge gaps complicate the assessment of damage risk

Expression analysis of Clavata1-like and Nodulin21-like genes from Pinus sylvestris during ectomycorrhiza formation

The ecology and physiology of ectomycorrhizal (EcM) symbiosis with conifer trees are well documented. In comparison, however, very little is known about the molecular regulation of these associations. In an earlier study, we identified three EcM-regulated Pinus expressed sequence tags (EST), two of which were identified as homologous to the Medicago truncatula nodulin MtN21. The third EST was a homologue to the receptor-like kinase Clavata1. We have characterized the expression patterns of these genes and of auxin- and mycorrhiza-regulated genes after induction with indole-3-butyric acid in Pinus sylvestris and in a time course experiment during ectomycorrhizal initiation with the co-inoculation of 2,3,5-triiodobenzoic acid, an auxin transport inhibitor. Our results suggest that different P. sylvestris nodulin homologues are associated with diverse processes in the root. The results also suggest a potential role of the Clv1-like gene in lateral root initiation by the ectomycorrhizal fungus

Molecular characterization of native and processed waxy maize starch in relation to the recrystallization behavior of model systems and starch microspheres

The recrystallization behavior of five starch materials, native waxy maize starch, and starches modified by acid hydrolysis and mechanical treatments, were investigated by DSC (differential scanning calorimetry) and electron microscopy (SEM). The starches were known to vary significantly in molecular weights but not in the degree of branching. Microspheres manufactured from one of these starches were also studied by both methods. The acid hydrolysis did not produce major breakdown of the granular structure of starch as evidenced by SEK or the amount of crystalline amylopectin, as measured by DSC, but broadened the melting temperature range compared to native starch. No crystallinity could be detected in the material after the mechanical treatment, which also seemed to destroy the granular structure. The crystallinity was regained after the material had been dispersed in 70 % water during heating followed by 20 hour storage at 6 degreesC, called as one-step temperature treatment, while within the set of samples stored at 20 degreesC only one of the starches showed presence of regained crystallinity. No significant differences could be observed with regard to endothermic transition temperature or temperature range between the samples of native starch and both the acid hydrolysed and the mechanically treated samples, as measured by DSC. Apparently from the enthalpy values and presence of endothermic transitions, amylopectin molecular weight and modification method seemed to affect the amount of starch crystallites formed and/or the recrystallization rates, with acid hydrolysed samples showing higher enthalpy values compared to mechanically treated samples. The same conclusion, as for one-step temperature treatment of starch materials, was done for a two-steps temperature treatment of the starch materials, regarding transitions temperatures within the set of experiment. The two-steps treatment with nucleation at a lower temperature and crystal growth and perfection at a higher temperature resulted in an increase in the melting temperatures and narrower melting intervals. This treatment is also similar to the actual microsphere manufacture process. DSC thermogram of placebo starch microspheres revealed that the crystallites, obtained in production process of the microspheres, melted at temperatures similar to melting temperatures of the starch dispersion after 14 days/6 degreesC- storage but showed higher enthalpy value and smaller melting interval