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).

Discrimination of Salix caprea, Salix gracilistyla, and Their Interspecific Hybrid Using Vegetative Characteristics and Partial Least Squares Discriminant Analysis

Identifying the morphological characteristics that distinguish plant varieties is an important issue for plant breeders and researchers. The objective of the present study was to create a partial least squares discrimination analysis (PLS-DA) model with morphological characteristics for species discrimination and to select the characteristics most important for species discrimination. Data for 27 vegetative characteristics were obtained from Salix caprea and Salix gracilistyla, and their interspecific hybrid (S. caprea × S. gracilistyla), and used for PLS-DA. According to this analysis, seven of the 27 characteristics were identified as those that most influenced species discrimination, and the PLS-DA model with these seven characteristics had a classification accuracy of 86% to 100%. The classification performance of this model was not significantly different from that of the model with all 27 characteristics (full model). Therefore, these results indicated that the three species can be relatively well distinguished by the seven characteristics extracted by PLS-DA. In addition, the selected characteristics can be used to select cross-breeding parents in subsequent breeding programs and to test the distinction, uniformity, and stability (DUS test) of the hybrid variety. From this perspective, PLS-DA is thought to be a useful methodology for classifying new plant varieties and providing information for breeding.

Co-solvent system of [EMIM]Ac and DMF to improve the enzymatic saccharification of pussy willow (Salix gracilistyla Miq.)

A co-solvent system consisting of 1-ethyl-3-methylimidazolium acetate ([EMIM]Ac)/N,N-dimethyl formamide (DMF) with different mass ratios was tested to improve the enzymatic saccharification of pussy willow (Salix gracilistyla Miq.). This system effectively lowered the viscosity and increased the biomass loading in the system. The water-soluble fraction obtained from the pure [EMIM]Ac remained constant or increased slightly as the amount of DMF was increased to 70%. At [EMIM]Ac/DMF ratios of 5/5 and 3/7, longer pretreatment times and higher temperatures increased the water-soluble fraction. The crystallinity of the pretreated product was increased by increasing amounts of DMF. The yield of enzymatic saccharification by means of this co-solvent system was comparable to that based on a pure [EMIM]Ac pretreatment, even though the glucose yield was slightly lower in case of DMF amount >70%. Expectedly, longer pretreatment times and higher temperatures improved the yield of enzymatic saccharification.

Clarifying Affiliations of Salix gracilistyla Miq. Cultivars and Hybrids

Salix gracilistyla Miq., japanese pussy willow or rosegold willow, is an ornamental shrub commonly cultivated for its prominent display of catkins in early spring. Verification of stocks of willows in the North American landscape nursery trade revealed that another name—Salix chaenomeloides Kimura—is associated frequently with plants similar to S. gracilistyla. Morphological analyses conducted during this study have shown that the S. chaenomeloides binomial is misapplied often to S. gracilistyla, its cultivars and hybrids. A comparison of the diagnostic characters of S. gracilistyla and S. chaenomeloides is presented to explain the differences between these taxa and to promote the adoption of the correct names. Five cultivars of S. gracilistyla valued for their early spring catkin displays, variegated foliage, and pendulous habits, and two cultivars of a hybrid origin are summarized. Also, two new ornamental cultivars called Salix ‘Winter Glory’ and Salix ‘Rabbit’s Foot’ are described.