Characterization of Miscanthus cell wall polymers

Efficient utilization of lignocellulosic Miscanthus biomass for the production of biochemicals, such as ethanol, is challenging due to its recalcitrance, which is influenced by the individual plant cell wall polymers and their interactions. Lignocellulosic biomass composition differs depending on several factors, such as plant age, harvest date, organ type, and genotype. Here, four selected Miscanthus genotypes (Miscanthus sinensis, Miscanthus sacchariflorus, Miscanthus × giganteus, Miscanthus sinensis × Miscanthus sacchariflorus hybrid) were grown and harvested, separated into stems and leaves, and characterized for their non‐starch polysaccharide composition and structures, lignin contents and structures, and hydroxycinnamate profiles (monomers and ferulic acid dehydrodimers). Polysaccharides of all genotypes are mainly composed of cellulose and low‐substituted arabinoxylans. Ratios of hemicelluloses to cellulose were comparable, with the exception of Miscanthus sinensis that showed a higher hemicellulose/cellulose ratio. Lignin contents of Miscanthus stems were higher than those of Miscanthus leaves. Considering the same organs, the four genotypes did not differ in their Klason lignin contents, but Miscanthus × giganteus showed the highest acetylbromide soluble lignin content. Lignin polymers isolated from stems varied in their S/G ratios and linkage type distributions across genotypes. p‐Coumaric acid was the most abundant ester‐bound hydroxycinnamte monomer in all samples. Ferulic acid dehydrodimers were analyzed as cell wall cross‐links, with 8‐5‐coupled diferulic acid being the main dimer, followed by 8‐O‐4‐, and 5‐5‐diferulic acid. Contents of p‐coumaric acid, ferulic acid, and ferulic acid dimers varied depending on genotype and organ type. The largest amount of cell wall cross‐links was analyzed for Miscanthus sinensis.     

Biomass yield in a genetically diverse Miscanthus sinensis germplasm panel evaluated at five locations revealed individuals with exceptional potential

To breed improved biomass cultivars of Miscanthus ×giganteus, it will be necessary to select the highest‐yielding and best‐adapted genotypes of its parental species, Miscanthus sinensis and Miscanthus sacchariflorus. We phenotyped a diverse clonally propagated panel of 569 M. sinensis and nine natural diploid M. ×giganteus at one subtropical (Zhuji, China) and five temperate locations (Sapporo, Japan; Leamington, Ontario, Canada; Fort Collins, CO; Urbana, IL; and Chuncheon, Korea) for dry biomass yield and 14 yield‐component traits, in trials grown for 3 years. Notably, dry biomass yield of four Miscanthus accessions exceeded 80 Mg/ha in Zhuji, China, approaching the highest observed for any land plant. Additionally, six M. sinensis in Sapporo, Japan and one in Leamington, Canada also yielded more than the triploid M. ×giganteus ‘1993‐1780’ control, with values exceeding 20 Mg/ha. Diploid M. ×giganteus was the best‐yielding group at the northern sites. Genotype‐by‐environment interactions were modest among the five northern trial sites but large between Zhuji, and the northern sites. M. sinensis accessions typically yielded best at trial sites with latitudes similar to collection sites, although broad adaptation was observed for accessions from southern Japan. Genotypic heritabilities for third year yields ranged from 0.71 to 0.88 within locations. Compressed circumference was the best predictor of yield. These results establish a baseline of data for initiating selection to improve biomass yield of M. sinensis and M. ×giganteus in a diverse set of relevant geographies.     

Miscanthus sinensis grassland is an indicator plant community to predict forest regeneration and development on ski slopes in Japan

Most ski slopes in Japan are established by forest clearcutting, scraping off the ground surface and thereby artificial seeding in well-developed forests. Recently, some ski slopes have been abandoned owing to economical failure, and more skis resorts will go bankrupt. To restore abandoned ski slopes, therefore, we have to find out appropriate indicators to restore forest cover with low cost. Vegetation data were collected in Yuzawa, central Honshu, Japan (500–760 m elevation), where ski slopes are over-concentrated. To predict the possibility of forest development, relationships between tree stem density and vegetation characteristics were examined. Trees did not establish in areas where the introduced plant cover was more than 40%. Of native grasslands, Miscanthus sinensis grassland showed the highest stem density but did not show high species richness. In particular, stem density increased with increasing M. sinensis cover. To indicate advanced successional sere towards forests, therefore, M. sinensis cover is a more appropriate indicator rather than species richness.     

Carbon budget and methane and nitrous oxide emissions over the growing season in a Miscanthus sinensis grassland in Tomakomai,Hokkaido, Japan

Species in the Miscanthus genus have been proposed as biofuel crops that have potential to mitigate elevated atmospheric carbon dioxide (CO₂) levels and nitrous oxide (N₂O) and methane (CH₄) emissions. Miscanthus sinensis is widespread throughout Japan and has been used for biomass production for centuries. We assessed the carbon (C) budget and N₂O and CH₄ emissions over the growing season for 2 years in a M. sinensis‐dominated grassland that was naturally established around 1972 in Tomakomai, Hokkaido, Japan, which is near the northern limit for M. sinensis grassland establishment on Andisols. Average C budget was ?0.31 Mg C ha^?1, which indicates C was released from the grassland ecosystem to the atmosphere. Dominant components in the C budget appeared to be aboveground net primary production of plants (1.94–2.80 Mg C ha^?1) and heterotrophic respiration (2.27–3.11 Mg C ha^?1). The measurement of belowground net primary production (BNPP) of plants in the M. sinensis grassland was extremely variable, thus only an approximate value could be calculated. Mean C budget calculated with the approximated BNPP value was 1.47 and ?0.23 Mg C ha^?1 for 2008 and 2009, respectively. Given belowground biomass (9.46–9.86 Mg C ha^?1) was 3.1–6.5 times higher than that of aboveground biomass may provide additional evidence suggesting this grassland represents a C sink. Average CH₄ emissions across years of ?1.34 kg C ha^?1 would indicate this grassland acts as an atmospheric CH₄ sink. Furthermore, average N₂O emissions across years were 0.22 kg N ha^?1. While the site may contribute N₂O to the atmosphere, this value is lower compared with other grassland types. Global warming potential calculated with the approximated BNPP value was ?5.40 and 0.95 Mg CO₂ Eq ha^?1 for 2008 and 2009, respectively, and indicates this grassland could contribute to mitigation of global warming.     

Synthetic polyploid production of Miscanthus sacchariflorus,Miscanthus sinensis,and Miscanthus x giganteus

Plants from the genus Miscanthus are potential renewable sources of lignocellulosic biomass for energy production. A potential strategy for Miscanthus crop improvement involves interspecific manipulation of ploidy levels to generate superior germplasm and to circumvent reproductive barriers for the introduction of new genetic variation into core germplasm. Synthetic autotetraploid lines of Miscanthus sacchariflorus and Miscanthus sinensis, and autoallohexaploid Miscanthus x giganteus were produced in tissue culture from oryzalin treatments to seed‐ and immature inflorescence‐derived callus lines. This is the first report of the genome doubling of diploid M. sacchariflorus. Genome doubling of diploid M. sinensis, M. sacchariflorus, and triploid M. x giganteus to generate tetraploid and hexaploid lines was confirmed by stomata size, nuclear DNA content, and chromosome counts. A putative pentaploid line was also identified among the M. x giganteus synthetic polyploid lines by nuclear DNA content and chromosome counts. Comparisons of phenotypic performance of synthetic polyploid lines with their diploid and triploid progenitors in the greenhouse found species‐specific differences in plant tiller number, height, and flowering time among the doubled lines. Stem diameter tended to increase after polyploidization but there were no significant improvements in biomass traits. Under field conditions, M. x giganteus synthetic hexaploid lines showed greater phenotypic variation, in terms of plant height, stem diameter, and tiller number, than their progenitor lines. Production of synthetic autopolyploid lines displaying significant phenotypic variation suggests that ploidy manipulation can introduce useful genetic diversity in the limited Miscanthus germplasm currently available in the United States. The role of polyploidization in the evolution and breeding of the genus Miscanthus is discussed.     

Variability and adaptability of Miscanthus species evaluated for energy crop domestication

A growing body of evidence indicates that second‐generation energy crops can play an important role in the development of renewable energy and the mitigation of climate change. However, dedicated energy crops have yet to be domesticated in order to fully realize their productive potential under unfavorable soil and climatic conditions. To explore the possibility of domesticating Miscanthus crops in northern China where marginal and degraded land is abundant, we conducted common garden experiments at multiple locations to evaluate variation and adaptation of three Miscanthus species that are likely to serve as the wild progenitors of the energy crops. A total of 93 populations of Miscanthus sinensis, Miscanthus sacchariflorus, and Miscanthus lutarioriparius were collected across their natural distributional ranges in China and grown in three locations that represent temperate grassland with cold winter, the semiarid Loess Plateau, and relatively warm and wet central China. Evaluated with growth traits such as plant height, tiller number, tiller diameter, and flowering time, the Miscanthus species showed high levels of genetic variation within and between species. There were significant site × population interactions for almost all traits of M. sacchariflorus and M. sinensis, but not M. lutarioriparius. The northern populations of M. sacchariflorus had the highest establishment rates at the most northern site owing to their strong cold tolerance. An endemic species in central China, M. lutarioriparius, produced not only the highest biomass of the three species but also higher biomass at the Loess Plateau than the southern site near its native habitats. These results demonstrated that the wild species harbored a high level of genetic variation underlying traits important for crop establishment and production at sites that are colder and drier than their native habitats. The natural variation and adaptive plasticity found in the Miscanthus species indicated that they could provide valuable resources for the development of second‐generation energy crops.     

Suitability of the biomass crop Miscanthus sinensis as a host for the aphids Rhopalosiphum padi (L.) and Rhopalosiphum maidis (F.), and its susceptibility to the plant luteovirus Barley Yellow Dwarf Virus

1 The reproductive performance of two aphid pest species, Rhopalosiphum padi and Rhopalosiphum maidis, was investigated on two seedling growth stages of Miscanthus sinensis, rhizomatous M. sinensis‘Giganteus’ and barley. Rhopalosiphum padi was unable to complete its development on Miscanthus. Rhopalosiphum maidis was most fecund on rhizomatous plants compared with seedling stages. 2 The ability of R. maidis to transmit the RPV isolate of Barley Yellow Dwarf Virus (BYDV) to M. sinensis seedlings was further investigated. Following successful transmission, host plant symptomology and the effect of infection on the yield of Miscanthus were investigated. Total above soil biomass was reduced by around 23% following infection. 3 The inability of R. padi to utilize Miscanthus is reviewed in light of this species’ origin and inability to utilize C₄ host plants. 4 The potential pest status of R. maidis on Miscanthus is discussed together with the impact that Miscanthus cultivation could have on the ecology of this aphid species and BYDV in the U.K.     

Improved Feedstock Option or Invasive Risk? Comparing Establishment and Productivity of Fertile <Emphasis Type="Italic">Miscanthus × giganteus</Emphasis> to <Emphasis Type="Italic">Miscanthus sinensis</Emphasis>

The perennial grass genus Miscanthus has great promise as biomass feedstock, but there are concerns about potential invasion outside production fields. While the sterile hybrid Miscanthus × giganteus is currently one of the leading feedstock options due to its low invasive potential, fertile varieties are being developed to reduce establishment costs, and their invasive risks need to be further assessed. We performed seed addition experiments in Ohio and Iowa, USA to examine the establishment, flowering, persistence, and shoot biomass per plot of a fertile M. × giganteus biotype (‘PowerCane’) and two Miscanthus sinensis biotypes, one feral, and one ornamental. Seeds were added to small, replicated plots in each of the 2 years under two seeding densities and two competition treatments, and plots were monitored for 2–3 years. The ‘PowerCane’ biotype established better, survived better, and produced greater amounts of biomass per plot than both M. sinensis biotypes. All three biotypes flowered by the second or third year after establishment, with inflorescences more numerous in ‘PowerCane’ and the Ornamental M. sinensis biotypes. Effects of seeding density and competition on these patterns were minor in most cases. Our research suggests that ‘PowerCane’ exhibits many traits shared by both biomass crops and invasive species: multi-year persistence, high biomass potential, and fertility. We suggest that the benefits of a seeded M. × giganteus should be carefully weighed against its increased invasive risk prior to deployment across the landscape.     

Early herbaceous succession along a topographical gradient on forest clear-felling sites in mountainous terrain,central Japan

Early successional patterns of herbaceous communities in forest clear-felling sites were investigated along a topographical gradient, which included ridge, slope and valley habitat types, in warm-temperate evergreen forest regions of central Japan for 5 years. Three dominant species with wind-dispersed seeds played a major role in the succession: an annual,Crassocephalum crepidioides, a biennial,Erigeron canadensis, and a perennial,Miscanthus sinensis. Pioneer herbs that have a seed-bank strategy, which are common in old field succession, were not found in the mountainous sites. The persistence of the annual or biennial dominants during the very early stages of secondary succession was different in the three topographical habitat types. In the ridge habitat,M. sinensis dominated from the first year state, andC. crepidioides andE. canadensis were less prominent.Crassocephalum crepidioides andE. canadensis became dominant as one moved down the slope. In the valley habitat,C. crepidioides dominated in the first year stage, was succeeded byE. canadensis in the second year, and thenM. sinensis gradually replaced it in later years. As all three wind-dispersed dominants simultaneously invaded in all the habitat types after clear-felling, the different successional patterns along the topographical gradient might have resulted from differences in the establishment ability and the growth rate of the three dominants depending on the three habitat types.     

Phylogenetic analysis of chloroplast restriction enzyme site mutations in the Saccharinae Griseb. subtribe of the Andropogoneae Dumort. tribe

Chloroplast (cp) DNA from 32 genotypes representing eight genera and 19 species from the Andropogoneae tribe was analyzed using 15 restriction enzymes and Southern hybridization with 12 cpDNA probes that span the complete rice chloroplast genome. Six of the genera, Saccharum, Miscanthus, Erianthus, Narenga, Eccoilopus, and Sclerostachya, are part of the Saccharinae subtribe, whereas the other two, Zea and Sorghum, were used as outgroups. Narenga, Miscanthus, Erianthus, and Sclerostachya are presumed to have been involved in the evolution of Saccharum officinarum (noble or high sucrose sugarcane) via S. spontaneum and S. robustum. Southern hybridization with the rice cpDNA probes surveyed approximately 3% of the S. officinarum Black Cheribon genome and yielded 62 restriction site mutations (18 informative) that were analyzed using cladistic parsimony and maximum likelihood. These site mutations placed the 32 genotypes into nine different chloroplast groups; seven from within the Saccharinae subtribe and the two outgroups (maize and Sorghum). Phylogenetic inferrence under various assumptions showed that the maternal lineages of Narenga, Miscanthus, Sclerostachya, and Saccharum formed a monophyletic group. This group displayed little variation. On the other hand, 5 of 6 Erianthus species and Eccoilopus longisetosus formed a separate group. The Old World Erianthus/Eccoilopus chloroplast was very different from that of the rest of the Saccharum complex members and was slightly more related to that of Sorghum bicolor. Placement of these Erianthus/Eccoilopus genotypes was, therefore, in conflict with analyses based on morphology. Surprisingly, Erianthus trinii, a New World species, had the same restriction sites as did one Miscanthus sinensis. One Miscanthus sp. from New Guinea that has a very high chromosome number (2n=192) had the same restriction sites as the majority of the Saccharum genus, suggesting that introgression between these genera occurs in the wild. The Saccharum genus was separated into two clades by single site mutation: one containing S. spontaneum, and the other containing all of the remaining Saccharum species and all 8 commerical hybrids (from various regions of the world). A physical map of the chloroplast of Saccharum officinarum Black Cheribon was constructed using 5 restriction enzymes.     

Effects of grassland succession on communities of small mammals in Illinois, USA

Native grasslands are among the most imperiled of the North American ecosystems, with only ∼4% of their pre-settlement area remaining, but some grassland habitats are being restored and maintained through such methods as prescribed burning and mowing, which may provide habitat for animal species endemic to this ecosystem. I determined how succession of the plant community, due to a four-year rotational burn in 16 grassland fragments, influenced species richness and local abundances of small mammals in Illinois, USA. Species richness was relatively low in grasslands that were recently burned and highest in older successional grasslands. The most abundant species, Microtus ochrogaster, M. pennslyvanicus, Peromyscus maniculatus, P. leucopus, and Reithrodontomys megalotis showed very different responses to succession; Microtus spp. were most abundant in older successional grasslands, preferring areas with more cover of bunchgrasses, whereas the other three species were relatively abundant in grasslands of all successional ages. P. maniculatus was most abundant in any habitat that had ample open ground. The grasslands at my study site are a mixture of restored and non-restored grasslands. Overall, adding additional time between burns and restoring more of the grasslands by planting bunchgrasses that are native to this area may increase abundances of most mammal species at my study site.     

Plant morphology,genome size,and SSR markers differentiate five distinct taxonomic groups among accessions in the genus Miscanthus

Information on genome size, ploidy level, and genomic polymorphisms among accessions of the genus Miscanthus can assist in taxonomic studies, help understand the evolution of the genus, and provide valuable information to biomass crop improvement programs. Taxonomic investigation combining variation in plant morphology, genome size, chromosome numbers, and simple sequence repeat (SSR) marker polymorphisms were applied to characterize 101 Miscanthus accessions. A total of 258 amplicons generated from 17 informative SSR primer pairs was subjected to cluster and principal coordinate analysis and used to characterize genetic variation and relationships among 31 Miscanthus accessions, including four interspecific Miscanthus hybrids created from controlled pollinations, and four Saccharum, six Erianthus, and one Sorghum bicolor accessions. Miscanthus accessions were distinct from accessions in the genera Erianthus and Saccharum. Miscanthus accessions fell into five taxonomic groups, including the existing taxonomic section Miscanthus, diploid and tetraploid Miscanthus sacchariflorus, and a fourth (M. × giganteus) and fifth group (Miscanthus ‘purpurascens’); the last two being intermediate forms. In contrast to previous work, our findings suggest diploid and tetraploid M. sacchariflorus are taxonomically different, the latter more closely related to M. sacchariflorus var lutarioriparius. We also suggest that Miscanthus ‘purpurascens’ accessions are interspecific hybrids between Miscanthus sinensis and diploid M. sacchariflorus based on DNA content and SSR polymorphisms. The evolution of Miscanthus and related genera is discussed based on combined analysis and geographical origin.     

Chilling tolerance and early vigour-related characteristics evaluated in two Miscanthus genotypes

A long growing season, mediated by the ability to grow at low temperatures early in the season, can result in higher yields in biomass of crop Miscanthus. In this paper, the chilling tolerance of two highly productive Miscanthus genotypes, the widely planted Miscanthus × giganteus and the Miscanthus sinensis genotype ‘Goliath’, was studied. Measurements in the field as well as under controlled conditions were combined with the main purpose to create basic comparison tools in order to investigate chilling tolerance in Miscanthus in relation to its field performance. Under field conditions, M. × giganteus was higher yielding and had a faster growth rate early in the growing season. Correspondingly, M. × giganteus displayed a less drastic reduction of the leaf elongation rate and of net photosynthesis under continuous chilling stress conditions in the growth chamber. This was accompanied by higher photochemical quenching and lower nonphotochemical quenching in M. × giganteus than that in M. sinensis ‘Goliath’ when exposed to chilling temperatures. No evidence of impaired stomatal conductance or increased use of alternative electron sinks was observed under chilling stress. Soluble sugar content markedly increased in both genotypes when grown at 12°C compared to 20°C. The concentration of raffinose showed the largest relative increase at 12°C, possibly serving as a protection against chilling stress. Overall, both genotypes showed high chilling tolerance for C₄ plants, but M. × giganteus performed better than M. sinensis ‘Goliath’. This was not due to its capacity to resume growth earlier in the season but rather due to a higher growth rate and higher photosynthetic efficiency at low temperatures.     

Evaluation of Pre-Emergence and Post-Emergence Herbicides for Weed Management in <i>Miscanthus sacchariflorus</i> and <i>Miscanthus sinensis</i>

Miscanthus, is a promising bioenergy crop, considered superior to other bioenergy crops because of its higher water and nutrient use efficiency, cold tolerance, and higher production of biomass. Broadleaf weeds and grass weeds, cause major problems in the Miscanthus field. A field experiment was conducted in 2018 and 2019, to assess the effects of pre-emergence (alachlor and napropamide) and post-emergence herbicides (nicosulfuron, dicamba, bentazon, and glufosinate ammonium) on broadleaf and grass weeds in M. sinensis and M. sacchariflorus fields. The weed control efficiency and phytotoxicity of pre- and post-emergence herbicides were evaluated at 30 days after treatment (DAT) and compared to those of the control plots. The results showed wide variations in the susceptibility of the weed species to the treated herbicides. Treatment with nicosulfuron 40 g.a.i.ha⁻¹ provided the most effective overall weed control (with 10% visual injury), without affecting the height and biomass of neither Miscanthus species in the field. Post-emergence herbicides such as glufosinate ammonium 400 g.a.i.ha⁻¹ and dicamba 482 g.a.i.ha⁻¹ were effective and inhibited the growth and density of the majority of weeds to a 100%; however, they showed significant phytotoxicity (toxicity scale of 1–10) to both species of Miscanthus. The application of glufosinate ammonium caused severe injuries to the foliar region (90% visual injury) of both Miscanthus sps. Comparatively, M. sinensis showed a slightly higher tolerance to the herbicides nicosulfuron, bentazon and napropamide with 10% visual injury at the recommended dose than M. sacchariflorus. The present study clearly showed that infestation of broadleaf and grass weeds in Miscanthus fields can cause significant damage to the growth and biomass of Miscanthus and applying pre-emergence and post-emergence herbicides effectively controls the high infestation of these weeds.     

Seasonal succession of phytoplankton in a lake of the Paraná river floodplain,Argentina

Phytoplankton biomass, morphological and taxonomic composition, species diversity and productivity were analyzed in a shallow lake of the Middle Paraná River floodplain (El Tigre, 31 ° 41 S and 60° 42 W), between November 1986 and July 1988. Lake inundation (filling and through-flow phases) constituted an intense long-term perturbation in the physical and chemical environment. As the lake filled with river water, K-selected species (netplanktonic filamentous bluegreens, > 37 µm, with low surface area/volume (SA/V) ratios) that had existed prior to filling (late spring 1986) were replaced in summer-fall by r-selected species (nannoplanktonic chlorophytes and cryptophytes, < 37 µm, mainly stout forms with high SA/V ratios). During the through-flow phase, lentic phytoplankton was replaced by lotic flagellate populations due to the direct flushing by river water. During the period of falling water (drainage and isolation phases), nanoplanktonic algae with similar characteristics to those of the filling phase dominated in late winter-spring. Later in the isolation phase, these were succeeded by K-selected species (netplanktonic algae, mainly motile spherical dinoflagellates and filamentous bluegreens with low SA/V ratios). Simultaneously, primary production per unit biomass decreased and total biomass and specific diversity increased. Seasonal changes of phytoplankton in floodplain lakes can be interpreted as the interaction between true successional development (as observed in the drainage and isolation phases) and intermediate disturbance. Using Reynolds' terminology, short-term disturbance (slight inflow of nutrient-rich river water) caused reversion to an earlier stage in the former succession, and long-term disturbance (lake inundation) truncated the successional progression and a new (or shifted) succession was initiated.     

Genome‐wide association and genomic prediction for biomass yield in a genetically diverse Miscanthus sinensis germplasm panel phenotyped at five locations in Asia and North America

To improve the efficiency of breeding of Miscanthus for biomass yield, there is a need to develop genomics‐assisted selection for this long‐lived perennial crop by relating genotype to phenotype and breeding value across a broad range of environments. We present the first genome‐wide association (GWA) and genomic prediction study of Miscanthus that utilizes multilocation phenotypic data. A panel of 568 Miscanthus sinensis accessions was genotyped with 46,177 single nucleotide polymorphisms (SNPs) and evaluated at one subtropical and five temperate locations over 3 years for biomass yield and 14 yield‐component traits. GWA and genomic prediction were performed separately for different years of data in order to assess reproducibility. The analyses were also performed for individual field trial locations, as well as combined phenotypic data across groups of locations. GWA analyses identified 27 significant SNPs for yield, and a total of 504 associations across 298 unique SNPs across all traits, sites, and years. For yield, the greatest number of significant SNPs was identified by combining phenotypic data across all six locations. For some of the other yield‐component traits, greater numbers of significant SNPs were obtained from single site data, although the number of significant SNPs varied greatly from site to site. Candidate genes were identified. Accounting for population structure, genomic prediction accuracies for biomass yield ranged from 0.31 to 0.35 across five northern sites and from 0.13 to 0.18 for the subtropical location, depending on the estimation method. Genomic prediction accuracies of all traits were similar for single‐location and multilocation data, suggesting that genomic selection will be useful for breeding broadly adapted M. sinensis as well as M. sinensis optimized for specific climates. All of our data, including DNA sequences flanking each SNP, are publicly available. By facilitating genomic selection in M. sinensis and Miscanthus × giganteus, our results will accelerate the breeding of these species for biomass in diverse environments.     

First Report of Pseudomonas lurida Causing Bacterial Leaf Spot on Miscanthus sinensis

Miscanthus spp. are large perennial wetland grasses that are receiving considerable attention as bioenergy crops. In late summer 2011, leaf spot symptoms were observed in a field of Miscanthus sinensis in Jeongseon, Gangwon province, Korea. Bacterial strains that belonged to the γ‐Proteobacteria genus Pseudomonas were isolated from the affected leaves. By phylogenetic analysis and phenotypic characterization, the representative strain MDM‐03 was identified as Pseudomonas lurida. Healthy M. sinensis leaves inoculated with MDM‐03 developed leaf spots similar to those observed in field. Bacteria re‐isolated from the leaf lesions were identical to the original strain MDM‐03 based on their cultural characteristics and 16S rDNA sequencing. This is the first report of bacterial leaf spot in Miscanthus sinensis.     

Plant species effect on the decomposition and chemical changes of leaf litter in grassland and pine and oak forest soils

Aims

The aim of this study was to examine the effect of plant species differing in functional and phylogenetic traits on the decomposition processes of leaf litter in a grassland of Japanese pampas grass (Miscanthus sinensis) and adjacent forests of Japanese red pine (Pinus densiflora) and Japanese oak (Quercus crispula), representing sequential stages of secondary succession.

Methods

The litterbag experiments were carried out for 3 years in a temperate region of central Japan.

Results

The decomposition constant (Olson’s k) was 0.49, 0.39, and 0.56/year for grass, pine, and oak, respectively. Nitrogen mass decreased in grass leaf litter during decomposition, whereas the absolute amount of nitrogen increased in leaf litter of pine and oak during the first year. Holocellulose in grass leaf litter decomposed selectively over acid-unhydrolyzable residues more markedly than in leaf litter of pine and oak. ¹³C nuclear magnetic resonance analysis also revealed a decrease in the relative area of O-alkyl-C in grass.

Conclusions

The different decomposition among the three litter species implied that the secondary succession from grassland to pine forest and from pine to oak forests could decrease and increase, respectively, the rate of accumulation and turnover of organic materials and N in soils.