Poplars In China Research Articles

Analysis of the Antennal Transcriptome and Identification of Tissue-specific Expression of Olfactory-related Genes in Micromelalopha troglodyta (Lepidoptera: Notodontidae).

Micromelalopha troglodyta (Graeser) has been one of the most serious pests on poplars in China. We used Illumina HiSeq 2000 sequencing to construct an antennal transcriptome and identify olfactory-related genes. In total, 142 transcripts were identified, including 74 odorant receptors (ORs), 32 odorant-binding proteins (OBPs), 13 chemosensory proteins (CSPs), 20 ionotropic receptors (IRs), and 3 sensory neuron membrane proteins (SNMPs). The genetic relationships were obtained by the phylogenetic tree, and the tissue-specific expression of important olfactory-related genes was determined by quantitative real-time PCR (qRT–PCR). The results showed that most of these genes are abundantly expressed in the antennae and head. In most insects, olfaction plays a key role in foraging, host localization, and searching for mates. Our research lays the foundation for future research on the molecular mechanism of the olfactory system in M. troglodyta. In addition, this study provides a theoretical basis for exploring the relationship between M. troglodyta and their host plants, and for the biological control of M. troglodyta using olfactory receptor as targets.

Identification and expression patterns of chemosensory proteins in the black-back prominent moth, Clostera restitura (Lepidoptera: Notodontidae)

Insects have evolved highly specific and sensitive olfactory sensory systems to detect plant hosts and mates. Chemosensory proteins (CSPs) play an important role in this process, but in this respect there is limited information on Clostera restitura, one of the most destructive defoliators of poplars in China. In the present study, we first identified seven candidate CSPs in C. restitura. Sequence alignment and phylogenetic analysis showed that these candidate proteins possessed typical characteristics of the insect CSP family and were similar to those of other Lepidoptera. These genes were expressed in different developmental stages and tissues, and the levels of expression differed after mating. Some CresCSPs were more associated with development and others with mating. They may play an important role in host recognition, egg development and mating behaviour. Furthermore, the CSPs were ubiquitously detected in all tissues and most of them were highly expressed in antennae, especially female antennae. We suggest the CresCSPs may contribute to female oviposition site recognition. CresCSPs that are highly transcribed in wings and legs, may function in gustation. This study provides a better understanding of the molecular mechanisms of olfaction in C. restitura and environmentally friendly pest management strategy for controlling C. restitura.

Antennal transcriptome analysis and expression profiles of odorant binding proteins in Clostera restitura

Clostera restitura Walker (Lepidoptera: Notodontidae) is one of the most destructive defoliators of poplars in China. We constructed an antennal transcriptome using Illumina Hiseq 2500™ sequencing and characterized the expression profiles of odorant binding proteins for better understanding of the olfactory receptive system and the role of putative olfactory proteins in C. restitura. A total of 165 transcripts were identified, including 43 transcripts encoding putative odorant-binding proteins (OBPs), 13 chemosensory proteins (CSPs), 78 odorant receptors (ORs), 15 ionotropic receptors (IRs), 13 gustatory receptors (GRs), and 3 sensory neuron membrane proteins (SNMPs). Furthermore, we systematically analyzed expression patterns of eight OBPs from different tissues of both C. restitura sexes by using reverse transcription PCR and quantitative real time PCR (RT-qPCR). The expression level of CresGOBP2 in female antennae was approximately two times higher than in males, and two pheromone binding proteins PBPs (CresPBP1 and -PBP3) and three OBPs (CresOBP9, −10, and −16) were more highly enriched in male antennae than in female antennae. CresOBP10 showed a remarkably high expression in legs compared to other studied insects. Our results suggested that these proteins might play a key role in foraging, seeking mates, and host recognition in C. restitura. Our findings provided a foundation for future studies on the molecular mechanisms controlling the olfactory system in C. restitura and potential novel targets for pest control strategies.

The Current Status and Development of Insect-Resistant Genetically Engineered Poplar in China.

Poplar is one of the main afforestation tree species in China, and the use of a single, or only a few, clones with low genetic diversity in poplar plantations has led to increasing problems with insect pests. The use of genetic engineering to cultivate insect-resistant poplar varieties has become a hot topic. Over the past 20 years, there have been remarkable achievements in this area. To date, nearly 22 insect-resistant poplar varieties have been created and approved for small-scale field testing, environmental release, or pilot-scale production. Here, we comprehensively review the development of insect-resistant genetically modified (GM) poplars in China. This review mostly addresses issues surrounding the regulation and commercialization of Bt poplar in China, the various insecticidal genes used, the effects of transgenic poplars on insects, toxic protein expression, multigene transformation, the stability of insect resistance, and biosafety. The efficacy of GM poplars for pest control differed among different transgenic poplar clones, larval instars, and insect species. The Bt protein analysis revealed that the expression level of Cry3A was significantly higher than that of Cry1Ac. Temporal and spatial studies of Bt protein showed that its expression varied with the developmental stage and tissue. The inheritance and expression of the exogenous gene were reviewed in transgenic hybrid poplar progeny lines and grafted sections. Biosafety issues, in terms of transgene stability and the effects on soil microorganisms, natural enemies of insects, and arthropod communities are also discussed.

The current status and development of insect-resistant genetically engineered poplar in China

Poplar is one of the main afforestation tree species in China, and the use of a single, or only a few, clones with low genetic diversity in poplar plantations has led to increasing problems with insect pests. The use of genetic engineering to cultivate insect-resistant poplar varieties has become a hot topic. Over the past 20 years, there have been remarkable achievements in this area. To date, nearly 22 insect-resistant poplar varieties have been created and approved for small-scale field testing, environmental release, or pilot-scale production. Here, we comprehensively review the development of insect-resistant genetically modified (GM) poplars in China. This review mostly addresses issues surrounding the regulation and commercialization of Bt poplar in China, the various insecticidal genes used, the effects of transgenic poplars on insects, toxic protein expression, multigene transformation, the stability of insect resistance, and biosafety. The efficacy of GM poplars for pest control differed among different transgenic poplar clones, larval instars, and insect species. The Bt protein analysis revealed that the expression level of Cry3A was significantly higher than that of Cry1Ac. Temporal and spatial studies of Bt protein showed that its expression varied with the developmental stage and tissue. The inheritance and expression of the exogenous gene were reviewed in transgenic hybrid poplar progeny lines and grafted sections. Biosafety issues, in terms of transgene stability and the effects on soil microorganisms, natural enemies of insects, and arthropod communities are also discussed.

Concentration- and flux-based ozone dose–response relationships for five poplar clones grown in North China

Concentration- and flux-based O3 dose–response relationships were developed for poplars in China. Stomatal conductance (gs) of five poplar clones was measured to parameterize a Jarvis-type multiplicative gs model. The maximum gs and other model parameters varied between clones. The strongest relationship between stomatal O3 flux and total biomass was obtained when phytotoxic ozone dose (POD) was integrated using an uptake rate threshold of 7 nmol m−2 s−1. The R2 value was similar between flux-based and concentration-based dose–response relationships. Ozone concentrations above 28–36 nmol mol−1 contributed to reducing the biomass production of poplar. Critical levels of AOT40 (accumulated O3 exposure over 40 nmol mol−1) and POD7 in relation to 5% reduction in total biomass for poplar were 12 μmol mol−1 h and 3.8 mmol m−2, respectively.

Advances in biosafety studies on transgenic insect-resistant poplars in China

Advances in biosafety studies on transgenic insect-resistant poplars in China

Progress in the Study of Molecular Genetic Improvements of Poplar in China

AbstractThe poplar is one of the most economically important and intensively studied tree species owing to its wide application in the timber industry and as a model material for the study of woody plants. The natural resource of poplars in China is replete. Over the past 10 years, the application of molecular biological techniques to genetic improvements in poplar species has been widely studied in China. Recent advances in molecular genetic improvements of poplar, including cDNA library construction, gene cloning and identification, genetic engineering, gene expression, genetic linkage map construction, mapping of quantitative trait loci (QTL) and molecular‐assisted selection, are reviewed in the present paper. In addition, the application of modern biotechnology to molecular improvements in the genetic traits of the poplar and some unsolved problems are discussed.(Managing editor: Li‐Hui Zhao)

Research advance of biomass and carbon storage of poplar in China

This paper summarized the studies on biomass production, biomass growth models, biomass measurement, biomass and forest density, as well as carbon storage of poplars in China in recent 20 years. The existing problems on research of poplar biomass are discussed and some suggestions for enhancing biomass of poplars are put forward.

Progress and strategies in cross breeding of poplars in China

The advance in intrasection and intersection cross breeding of poplars in China over the past 50 years is reviewed. Great progress has been made in Sections Leuce and Aigeiros, and satisfactory results of intersection hybridization have been achieved in the crossing between Sections Tacamahaca and Aigeiros. The modes of hybridization include single cross, double cross, triple cross, backcross, etc. It is known that using hybrids as parents to cross with other species or hybrids is an effective and easy way to obtain heterosis. Fast growth, cold and drought tolerance, pest and disease resistance, narrow crowns and rootage, etc. are breeding goals. The conventional artificial crossing is still a major breeding method, and a combination of the conventional artificial crossing with physical radiation and chemical induction can create new triploid individuals that possess higher yield potential. The super clones cultivated have already displayed enormous socioeconomic and ecological benefits in practice. Finally, the problems that investigators have to face at present are discussed as well as some strategies in poplar cross breeding in China.

Morphological and molecular phylogenetic analysis of Melampsora species on poplars in China

Many species of Melampsora on Populus have been reported in China, based on morphological characteristics of both uredial and telial states, and on host species, but their morphology and taxonomy are still poorly defined. In this study, 196 specimens representing Melampsora species on poplars and collected from various areas of China were used for morphological observations. The morphological characteristics of urediniospores and teliospores were examined with light and scanning electron microscopy. The specimens could be classified into five groups based on their morphology. For the sequencing of the nuclear large subunit rDNA (D1/D2), 5.8S rDNA and their internal transcribed spacers, ITS1 and ITS2 region, 54 specimens were selected from the specimens used in morphological observations. These specimens were separated into six clades by phylogenetic analyses of the D1/D2 and ITS regions. Correlations among morphological groups and phylogenetic clades based on these results suggest a revision of these species. In particular, no evidence to discriminate specimens of M. acedioides, M. magnusiana, and M.rostrupii was found from either morphological characteristics or sequence analysis.

Diversity and breeding potential of poplar species in China

The genus Populus is composed of many species with an impressive variety of growth characteristics. Nevertheless, this abundant natural offering has been only partially utilized to date with the objective of promoting poplar breeding and cultivation. Following an old tradition, more or less inflexible production systems are mainly keyed to a few high-yielding P. x euramericana and P. x interamericana clones in most countries. Consequently, considerable economic failures have to be accepted repeatedly as a result of serious calamities.China ranks among the countries characterized by an exceptionally multifarious indigenous flora. Based on ample genetic variation, poplar species were able to settle in divergent habitats and to conserve the ability to survive and reproduce over long periods owing to adaptation processes. The diversity is concentrated, above all, in the subtropical mountain regions of southwest China. Comprehensive studies of the genus populus in the southern and eastern mountain chains of the Qinghai-Tibet Plateau turned out to be particularly impressive; 3 sections, 17 species and 15 varieties have been recorded and taxonomically classified there. They grow at altitudes between 1500 m and 4300 m above sea level. Many of these poplar sources are notable for their remarkable site adaptation even in harsh conditions and also for their fast and vigorous growth.Species expected to be suitable for international breeding and cultivation objectives in the near future are presented in a general way. The necessarily subjective selection is based on the state of available knowledge mainly about site requirements, environmental importance, growth characteristics, regeneration ability, silvicultural behaviour, yield estimation and wood utilization. In particular, the following species are characterized in the paper in an abridged fashion: P. cathayana, P. davidiana, P. euthratica, P. simonii, P. szechuanica, P. ussuriensis and P. yunnanensis.The potential of poplars in China is considered to be instrumental in expanding and stimulating poplar breeding activities worldwide. Measures to be specified in the paper are considered important and could be implemented on the basis of a close and confident co-operation with Chinese colleagues and institutes relevant to the subject and under the umbrella of the International Poplar Commission. Key words: poplar, tradition, calamities, China, genetic variation, promising species, characteristics, breeding priorities