Discovery of a Cryptic Species, Erysiphe Salicina Sp. Nov., and Reconstruction of The Phylogeny of Powdery Mildews On Populus and Salix Spp.

Recently performed phylogenetic-taxonomic analyses of species belonging to Erysiphe sect. Uncinula on willows (Salix spp.) demonstrated a much higher diversity than previously assumed. Phylogenetic analyses and morphological examinations of Chinese Erysiphe collections on Salix abscondita (= S. raddeana), S. sinica and S. taraikensis, all belonging to Salix subgen. Vetrix sect. Vetrix, revealed an additional cryptic species in sister position to the E. salicis clade, which is described as Erysiphe salicina. The new species clearly distinguished from all allied species in morphological and genetical results. The phylogeny of the new species and closely related species on Populus and Salix spp. (Salicaceae) was reconstructed and discussed using a combined alignment of the internal transcribed spacer (ITS) regions and 28S rDNA sequences. The present phylogenetic analyses suggest that the recently described E. salicicola (on Salix gracilistyla in South Korea) has to be reduced to synonymy with E. salicis var. salicis-gracilistylae (º Uncinula salicis-gracilistylae).

Nonadditive gene expression is correlated with nonadditive phenotypic expression in interspecific triploid hybrids of willow (Salix spp.)

Many studies have highlighted the complex and diverse basis for heterosis in inbred crops. Despite the lack of a consensus model, it is vital that we turn our attention to understanding heterosis in undomesticated, heterozygous, and polyploid species, such as willow (Salix spp.). Shrub willow is a dedicated energy crop bred to be fast-growing and high yielding on marginal land without competing with food crops. A trend in willow breeding is the consistent pattern of heterosis in triploids produced from crosses between diploid and tetraploid species. Here, we test whether differentially expressed genes are associated with heterosis in triploid families derived from diploid S. purpurea, diploid S. viminalis, and tetraploid S. miyabeana parents. Three biological replicates of shoot tips from all family progeny and parents were collected after 12 weeks in the greenhouse and RNA extracted for RNA-Seq analysis. This study provides evidence that nonadditive patterns of gene expression are correlated with nonadditive phenotypic expression in interspecific triploid hybrids of willow. Expression-level dominance was most correlated with heterosis for biomass yield traits and was highly enriched for processes involved in starch and sucrose metabolism. In addition, there was a global dosage effect of parent alleles in triploid hybrids, with expression proportional to copy number variation. Importantly, differentially expressed genes between family parents were most predictive of heterosis for both field and greenhouse collected traits. Altogether, these data will be used to progress models of heterosis to complement the growing genomic resources available for the improvement of heterozygous perennial bioenergy crops.

Leaf-Scale Study of Biogenic Volatile Organic Compound Emissions from Willow (Salix spp.) Short Rotation Coppices Covering Two Growing Seasons

In Europe, willow (Salix spp.) trees have been used commercially since the 1980s at a large scale to produce renewable energy. While reducing fossil fuel needs, growing short rotation coppices (SRCs), such as poplar or willow, may have a high impact on local air quality as these species are known to produce high amounts of isoprene, which can lead to the production of tropospheric ozone (O3). Here, we present a long-term leaf-scale study of biogenic volatile organic compound (BVOC) emissions from a Swedish managed willow site with the aim of providing information on the seasonal variability in BVOC emissions during two growing seasons, 2015–2016. Total BVOC emissions during these two seasons were dominated by isoprene (>96% by mass) and the monoterpene (MT) ocimene. The average standardized (STD, temperature of 30 °C and photosynthetically active radiation of 1000 µmol m−2 s−1) emission rate for isoprene was 45.2 (±42.9, standard deviation (SD)) μg gdw−1 h−1. Isoprene varied through the season, mainly depending on the prevailing temperature and light, where the measured emissions peaked in July 2015 and August 2016. The average STD emission for MTs was 0.301 (±0.201) μg gdw−1 h−1 and the MT emissions decreased from spring to autumn. The average STD emission for sesquiterpenes (SQTs) was 0.103 (±0.249) μg gdw−1 h−1, where caryophyllene was the most abundant SQT. The measured emissions of SQTs peaked in August both in 2015 and 2016. Non-terpenoid compounds were grouped as other VOCs (0.751 ± 0.159 μg gdw−1 h−1), containing alkanes, aldehydes, ketones, and other compounds. Emissions from all the BVOC groups decreased towards the end of the growing season. The more sun-adapted leaves in the upper part of the plantation canopy emitted higher rates of isoprene, MTs, and SQTs compared with more shade-adapted leaves in the lower canopy. On the other hand, emissions of other VOCs were lower from the upper part of the canopy compared with the lower part. Light response curves showed that ocimene and α-farnesene increased with light but only for the sun-adapted leaves, since the shade-adapted leaves did not emit ocimene and α-farnesene. An infestation with Melampsora spp. likely induced high emissions of, e.g., hexanal and nonanal in August 2015. The results from this study imply that upscaling BVOC emissions with model approaches should account for seasonality and also include the canopy position of leaves as a parameter to allow for better estimates for the regional and global budgets of ecosystem emissions.

New to Kazakhstan species of zygomycetes in forest soil of Trans-Ili Alatau and Kungey Alatau

This article provides data on two species of soil zygomycetes, new to Kazakhstan, found in the rhizosphere of various woody plants in the Trans-Ili and Kungey Alatau (Northern Tien Shan) – Piptocephalis cylindrospora and Lichtheimia corymbifera. P. cylindrospora is an obligate parasite of zygomycetous fungi; in the study area, it was found twice in Kungey Alatau on species Absidia spinosa and Lichtheimia corymbifera in the rhizosphere of Populus tremula. It does not cause a noticeable deterioration in the development of the host. Earlier, in Kazakhstan, only Piptocephalis arrhiza was registered in the rhizosphere of Armeniaca vulgaris, Populus tremula, Picea schrenkiana, Juniperus spp. Lichtheimia corymbifera, previously belonging to the genus Absidia, was recorded in the rhizosphere of Populus tremula in Kungey Alatau and in the rhizosphere of Picea schrenkiana, Salix sp., Crataegus sp. in Trans-Ili Alatau. L. corymbifera is characterized by heights of 1677 m in Kungey Alatau, and from 1516 to 2007 m a. s. l. in Trans-Ili Alatau. Until recently, in Kazakhstan, only a closely related species Absidia spinosa was isolated from the rhizosphere of Malus sieversii, Armeniaca vulgaris, Crataegus spp., Pinus sylvestris, Populus spp., Sorbus tianschanica, Picea schrenkiana, Salix spp. Descriptions of species colonies based on isolated pure cultures, morphological data, information on ecology and distribution are offered. In L. corymbiferacultures, the so-called “self-parasitism” is observed, in which the fungal hyphae colonize sporangiophores, and the latter look like penetrated by hyphae. The sexual stage of both species was not found in our studies.

Site-Effects Dominate the Plant Availability of Nutrients under Salix Species during the First Cutting Cycle

Fast-growing willows (Salix spp.) provide alternative sources of renewable energy generation, but need an adequate nutrient availability in the soil for high biomass production. In general, species mixtures can be more nutrient-efficient than pure cultures, but this is scarcely known for Salix spp. Therefore, this study evaluates the nutrient availability and P mobilization under two willow species, Salixdasyclados var. ‘Loden’ and S. schwerinii × viminalis var. ‘Tora’, grown as pure and mixed cultures at non-fertilized former arable sites in Germany (Stagnic Cambisol) and Sweden (Vertic Cambisol). The plant availability of potassium (K), magnesium (Mg) and phosphorus (P) and soil phosphatase activities in the topsoil were measured in spring of the year of planting (initial) and under 4 years-old stocks (one year after the first 3-year cutting cycle). The initial plant availability of the nutrients significantly differed between the sites and the two sampling dates at both sites. The plant availability of K and Mg was optimal to high at both sites and sampling dates, but rather low for P (after 4 years ≤5 mg P 100 g−1 soil). The plant-available P and K content in soil significantly decreased within the 4 years of willow growth at both sites. The acid and alkaline phosphatase activity in the soil of the German site (Rostock) was significantly lower after 4 years of willow growth, but differed not significantly between the two sampling dates at the Swedish site (Uppsala). Higher activity of acid phosphatase compared to alkaline phosphatase was recorded in the soils at both test sites based on the site-specific soil pH (<7). The slight decrease of plant availability of P after 4 years of Salix growth in pure culture differed not significantly between the different species. Mixed growth did not decrease the plant availability of P within this period, although no significant difference in the biomass production of pure and mixed growth was observed. This was valid at both sites, and therefore, seems independent of the site-specific differences in soil and climate conditions. The general validity of the assumptions should be tested also for other species mixtures and soil conditions in the future before site-adapted growth designs can be recommended in biomass production of Salix.

INTERNAL CAUSE ANALYSIS OF DAMAGE OF WOODEN COMPONENTS IN DANXIA TEMPLE ANCIENT ARCHITECTURES: TREE SPECIES

In the study, part of degraded wooden components of Danxia Temple ancient architectures in China were indentified through the bright field microscope, and chemical compositions in cell walls were observed using polarized and fluorescence lights, respectively. The results showed that samples were belonged to Quercus spp., Ulmus spp., Salix spp., and Populus spp., respectively. Cellulose composition in Quercus spp. was seriously consumed by brown decay fungi, cellulose and lignin compositions in Ulmus spp. were consumed by white decay fungi under polarized and fluorescence light observations. All of these four kind of tree species themselves were easily vulnerable to be attacked by insects.

Heat Stress in Broiler Chickens and the Effect of Dietary Polyphenols, with Special Reference to Willow (Salix spp.) Bark Supplements—A Review

Over the last decade, there has been a growing interest in the use of a wide range of phytoadditives to counteract the harmful effects of heat stress in poultry. Willow (Salix spp.) is a tree with a long history. Among various forms, willow bark is an important natural source of salicin, β-O-glucoside of saligenin, but also of polyphenols (flavonoids and condensed tannins) with antioxidant, antimicrobial, and anti-inflammatory activity. In light of this, the current review presents some literature data aiming to: (1) describe the relationship between heat stress and oxidative stress in broilers, (2) present or summarize literature data on the chemical composition of Salix species, (3) summarize the mechanisms of action of willow bark in heat-stressed broilers, and (4) present different biological effects of the extract of Salix species in different experimental models.