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Bamboo (Bambusa emeiensis) shoot, a nutritious food, easily attracts herbivores, including the bamboo weevil, Cyrtotrachelus buqueti. Scanning electron microscopy revealed that bamboo shoot shells (BSSs), the protective layers encasing bamboo shoots, are composed of closely packed fibers and bamboo shoot trichomes (BSTs) are divided into three types, including glandular trichome I, and non-glandular types II and III. To elucidate the underlying molecular defense mechanisms, 50 transcription factors (TFs) were chosen for qRT-PCR analyses of BSS and BST based on bamboo shoot transcriptome data. Among these, 8 and 23 genes were significantly differentially expressed in BSS and BST, respectively, indicating that BSS and BST responded to herbivory. BSS and non-glandular BST functioned as physical barriers and glandular BST released volatile compounds in defense against herbivory. Some TFs might act as mediators and participate in defense responses by BSS and BST.

Background Bamboo, a lignocellulosic feedstock, is considered as a potentially excellent raw material and evaluated for lignocellulose degradation and bioethanol production, with a focus on using physical and chemical pre-treatment. However, studies reporting the biodegradation of bamboo lignocellulose using microbes such as bacteria and fungi are scarce. Results In the present study, Bacillus velezensis LC1 was isolated from Cyrtotrachelus buqueti, in which the symbiotic bacteria exhibited lignocellulose degradation ability and cellulase activities. We performed genome sequencing of B. velezensis LC1, which has a 3929,782-bp ring chromosome and 46.5% GC content. The total gene length was 3,502,596 bp using gene prediction, and the GC contents were 47.29% and 40.04% in the gene and intergene regions, respectively. The genome contains 4018 coding DNA sequences, and all have been assigned predicted functions. Carbohydrate-active enzyme annotation identified 136 genes annotated to CAZy families, including GH, GTs, CEs, PLs, AAs and CBMs. Genes involved in lignocellulose degradation were identified. After a 6-day treatment, the bamboo shoot cellulose degradation efficiency reached 39.32%, and the hydrolysate was subjected to ethanol fermentation with Saccharomyces cerevisiae and Escherichia coli KO11, yielding 7.2 g/L of ethanol at 96 h. Conclusions These findings provide an insight for B. velezensis strains in converting lignocellulose into ethanol. B. velezensis LC1, a symbiotic bacteria, can potentially degrade bamboo lignocellulose components and further transformation to ethanol, and expand the bamboo lignocellulosic bioethanol production.

Background:The most severe insect damage to bamboo shoots is the bamboo-snout beetle (Cyrtotrachelus buqueti). Bamboo is a perennial plant that has significant economic value.C. buquetialso plays a vital role in the degradation of bamboo lignocellulose and causing damage. The genome sequencing and functional gene annotation ofC. buquetiare of great significance to reveal the molecular mechanism of its efficient degradation of bamboo fiber and the development of the bamboo industry.Results:The size ofC. buquetigenome was close to 600.92 Mb by building a one paired-end (PE) library and k-mer analysis. Then, we developed nine 20-kb SMRTbell libraries for genome sequencing and got a total of 51.12 Gb of the original PacBio sequel reads. Furthermore, after filtering with a coverage depth of 85.06×, clean reads with 48.71 Gb were obtained. The final size ofC. buquetigenome is 633.85 Mb after being assembled and measured, and the contig N50 ofC. buquetigenome is 27.93 Mb. The value of contig N50 shows that the assembly quality ofC. buquetigenome exceeds that of most published insect genomes. The size of the gene sequence located on chromosomes reaches 630.86 Mb, accounting for 99.53% of the genome sequence. A 1,063 conserved genes were collected at this assembled genome, comprising 99.72% of the overall genes with 1,066 using the Benchmark Uniform Single-Copy Orthology (BUSCO). Moreover, 63.78% of theC. buquetigenome is repetitive, and 57.15% is redundant with long-term elements. A 12,569 protein-coding genes distributed on 12 chromosomes were acquired after function annotation, of which 96.18% were functional genes. The comparative genomic analysis results revealed thatC. buquetiwas similar toD. ponderosae.Moreover, the comparative analysis of specific genes inC. buquetigenome showed that it had 244 unique lignocellulose degradation genes and 240 genes related to energy production and conversion. At the same time, 73P450genes and 30GSTgenes were identified, respectively, in theC. buquetigenome.Conclusion:The high-qualityC. buquetigenome has been obtained in the present study. The assembly level of this insect’s genome is higher than that of other most reported insects’ genomes. The phylogenetic analysis ofP450andGSTgene family showed thatC. buquetihad a vital detoxification function to plant chemical components.

Bambusa emeiensis is one of the most economically important bamboos, yet the yield and quality of this bamboo species continue to be challenged by insect herbivores. APETALA2/ethylene responsive factors (AP2/ERF) comprise a large family of plant transcription factors regulating numerous biological processes and playing critical roles in plant defence responses. In the present study, 47 AP2/ERF genes were identified and classified in the B. emeiensis herbivore-induced transcriptome. Based on AP2 domain numbers, conserved amino-acid residues, motif analyses and phylogenetic trees and BeAP2/ERF proteins were grouped into four subfamilies, namely AP2, ERF, Dehydration-responsive-element-binding (DREB) and Soloist, and these subfamilies consisted of nine, 23, 14 and 1 proteins, respectively. Amino-acid residue sequences of the AP2 domain in B. emeiensis were conserved compared with those in Arabidopsis thaliana. Expression analyses revealed that the treatment (herbivore damage) and control groups exhibited different expression patterns, and majority of BeERF/DREB genes were significantly and differentially expressed in the transcriptome, as verified using quantitative real-time PCR (qPCR). Finally, eight genes were selected for further PCR analyses of tissue-specific expression, of which the four tissues exhibited different expression patterns. Our data indicated that the genes encoding the ERF/DREB subfamily of B. emeiensis play critical roles in its response to herbivores.

Pseudoregma bambucicola is an economically significant bamboo pest which is highly reproductive found in Eastern Asia that influences the normal growth of bamboo, induces the formation of sooty mol...

The NAC (NAM-ATAF1/2-CUC) transcription factors (TFs) regulate numerous biological processes, such as growth, development, and stress responses. The yield and quality of Bambusa emeiensis, an economically important bamboo, decrease under stress caused by insect herbivores, such as Cyrtotrachelus buqueti. In the present study, 33 BeNACs, including 4 membrane-associated TFs, were identified in B. emeiensis transcriptome. Phylogenetic analysis revealed that BeNACs and their Arabidopsis thaliana counterparts clustered into 4 major groups, which were subdivided into 17 subgroups. Conserved motif and phylogenetic analyses revealed that BeNACs with close evolutionary relationships contained highly similar motifs. The N-terminal regions of BeNACs had NAC domains. In addition, the C-termini and transmembrane domains of four BeNACs contained transmembrane motifs. Transcriptome analysis revealed that majority of BeNACs were highly expressed under herbivory. The expression levels of eight BeNACs, including predicted stress-related and membrane-bound BeNACs, in bamboo shoots, shells, trichomes, and leaves and under two treatments (fed and unfed) were assessed through quantitative real-time polymerase chain reaction. Several BeNACs (BeNAC4, 10, 19, and 24) were considered as closely related to responses to herbivore. This study lays a foundation for future study of BeNACs’ functions in bamboo development and stress response.

Both leica microscopic camera system and scanning electron microscopy was used to observe and characterize the feet, back, abdomen, antennae and mouthparts of the Pseudoregma bambucicola from the bamboo, Bambusa multiplex. The possible functions of all the external morphological characteristics of the P. bambucicola were described and discussed in detail, which offers a basis for further enriching the biology, phylogeny and ecological niche of the P. bambucicola. Moreover, the morphological results should contribute to morphological identification and differentiation of the P. bambucicola from other aphids in the same family.

Background Gut symbiotic microbiota plays a critical role in nutrient supply, digestion, and absorption. The bamboo snout beetle, Cyrtotrachelus buqueti, a common pest of several bamboo species, exhibits high lignocellulolytic enzyme activity and contains various CAZyme genes. However, to date, no studies have evaluated the role of gut symbiotic microbiota of the snout beetle on bamboo lignocellulose degradation. Therefore, the present study investigated the role of gut symbiotic microbiota of C. buqueti on bamboo lignocellulose degradation. Results Gut symbiotic microbiota of female (CCJ), male (XCJ), and larvae (YCJ) beetles was used to treat bamboo shoot particles (BSPs) in vitro for 6 days. Scanning electron microscopy (SEM) revealed significant destruction of the lignocellulose structure after treatment, which was consistent with the degradation efficiencies of CCJ, XCJ, and YCJ for cellulose (21.11%, 17.58% and 18.74%, respectively); hemicellulose (22.22%, 27.18% and 34.20%, respectively); and lignin (19.83%, 24.30% and 32.97%, respectively). Gut symbiotic microbiota of adult and larvae beetles was then identified using 16sRNA sequencing, which revealed that four microbes: Lactococcus, Serratia, Dysgonomonas and Enterococcus, comprise approximately 84% to 94% of the microbiota. Moreover, the genomes of 45 Lactococcus, 72 Serratia, 86 Enterococcus and 4 Dysgonomonas microbes were used to analyse resident CAZyme genes. These results indicated that gut symbiotic microbiota of adult and larvae C. buqueti is involved in the lignocellulose degradation traits shown by the host. Conclusions This study shows that the gut symbiotic microbiota of C. buqueti participates in bamboo lignocellulose degradation, providing innovative findings for bamboo lignocellulose bioconversion. Furthermore, the results of this study will allow us to further isolate lignocellulose-degrading microbiota for use in bamboo lignocellulose bioconversion. Electronic supplementary material The online version of this article (10.1186/s13068-019-1411-1) contains supplementary material, which is available to authorized users.

Additional file 6: Figure S4. Relative abundance of PICRUSt-predicted CAZyme genes relevant to lignocellulose degradation. (A) Glycoside hydrolases (GHs). (B) Glycosyl transferases (GTs). (C) Carbohydrate esterases (CEs). (D) Carbohydrate-binding modules (CBMs). (E) Auxiliary activities (AAs).

Background As an important biomass raw material, the lignocellulose in bamboo is of significant value in energy conversion. The conversion of bamboo lignocellulose into fermentable reducing sugar, i.e. the degradation of bamboo lignocellulose, is an important step in lignocellulose conversion. However, little research has focussed on excavating the enzymes and microbes that are related to the degradation of bamboo lignocellulose, which is important for its utilisation. This study used Cyrtotrachelus buqueti (bamboo snout beetle) to evaluate the efficiency of bamboo lignocellulose degradation. Results RNA sequencing was conducted to sequence the transcriptome of the insect before and after feeding on bamboo shoots. The expression levels of genes encoding several carbohydrate-active enzymes, such as endoglucanase (evgtrinloc27093t1 and evgtrinloc16407t0) and laccase (evgtrinloc15173t0 and evgtrinloc11252t0), were found to be upregulated after feeding. Faecal component analysis showed that the degradation efficiencies of cellulose, hemicellulose and lignin were 61.82%, 87.65% and 69.05%, respectively. After 6 days of co-culture with crude enzymes in vitro, the degradation efficiencies of cellulose, hemicellulose and lignin in bamboo shoot particles (BSPs) were 24.98%, 37.52% and 26.67%, respectively. These results indicated that lignocellulosic enzymes and related enzymes within the insect itself co-degraded bamboo lignocellulose. These finding can potentially be used for the pre-treatment and enzymatic hydrolysis of bamboo lignocellulose. Conclusion Our results showed that intestinal digestive enzymes from C. buqueti degraded bamboo shoot lignocellulose both in vivo and in vitro. In addition, the expression levels of many carbohydrate-active enzyme (CAZyme) genes were upregulated in the transcriptome, including those for cellulase, xylanase and ligninase genes. Therefore, we proposed a scheme for applying the lignocellulolytic enzymes from C. buqueti to degrade bamboo lignocellulose using genetic, enzymatic and fermentation engineering techniques to overexpress the lignocellulolytic enzymes genes in vitro and obtain large quantities of enzymes that could efficiently degrade bamboo lignocellulose and be used for lignocellulose bioconversion. Electronic supplementary material The online version of this article (10.1186/s13068-019-1406-y) contains supplementary material, which is available to authorized users.

Background The bamboo weevil Cyrtotrachelus buqueti, which is considered a pest species, damages bamboo shoots via its piercing–sucking mode of feeding. C. buqueti is well known for its ability to transform bamboo shoot biomass into nutrients and energy for growth, development and reproduction with high specificity and efficacy of bioconversion. Woody bamboo is a perennial grass that is a potential feedstock for lignocellulosic biomass because of its high growth rate and lignocellulose content. To verify our hypothesis that C. buqueti efficiently degrades bamboo lignocellulose, we assessed the bamboo lignocellulose-degrading ability of this insect through RNA sequencing for identifying a potential route for utilisation of bamboo biomass. Results Analysis of carbohydrate-active enzyme (CAZyme) family genes in the developmental transcriptome of C. buqueti revealed 1082 unigenes, including 55 glycoside hydrolases (GH) families containing 309 GHs, 51 glycosyltransferases (GT) families containing 329 GTs, 8 carbohydrate esterases (CE) families containing 174 CEs, 6 polysaccharide lyases (PL) families containing 11 PLs, 8 auxiliary activities (AA) families containing 131 enzymes with AAs and 17 carbohydrate-binding modules (CBM) families containing 128 CBMs. We used weighted gene co-expression network analysis to analyse developmental RNA sequencing data, and 19 unique modules were identified in the analysis. Of these modules, the expression of MEyellow module genes was unique and the module included numerous CAZyme family genes. CAZyme genes in this module were divided into two groups depending on whether gene expression was higher in the adult/larval stages or in the egg/pupal stages. Enzyme assays revealed that cellulase activity was highest in the midgut whereas lignin-degrading enzyme activity was highest in the hindgut, consistent with findings from intestinal gene expression studies. We also analysed the expression of CAZyme genes in the transcriptome of C. buqueti from two cities and found that several genes were also assigned to CAZyme families. The insect had genes and enzymes associated with lignocellulose degradation, the expression of which differed with developmental stage and intestinal region. Conclusion Cyrtotrachelus buqueti exhibits lignocellulose degradation-related enzymes and genes, most notably CAZyme family genes. CAZyme family genes showed differences in expression at different developmental stages, with adults being more effective at cellulose degradation and larvae at lignin degradation, as well as at different regions of the intestine, with the midgut being more cellulolytic than the hindgut. This degradative system could be utilised for the bioconversion of bamboo lignocellulosic biomass. Electronic supplementary material The online version of this article (10.1186/s13068-018-1291-9) contains supplementary material, which is available to authorized users.

Picea wilsonii transcription factor PwNAC2 enhanced plant tolerance to salt and drought stress through multiple signaling pathway and interacted with PwRFCP1 to participate in flowering regulation. NAC is one of the largest transcription factor families in plants, however, its role is not yet fully understood. Here, we identified a transcription factor PwNAC2 in Picea wilsonii, which localized in nucleus with transcriptional activity in C-terminal region and can form homodimer by itself. Expression analysis by real-time PCR showed that PwNAC2 was induced by multiple abiotic stresses and phytohormones stimuli. PwRFCP1 (Resemble-FCA-contain-PAT1 domain), an interaction protein of PwNAC2 was screened via yeast two hybrid. Luciferase complementation assay confirmed the interaction in vivo and bimolecular fluorescence complementation assay showed the interaction in nucleus. PwNAC2 overexpression retarded Arabidopsis hypocotyls growth which is closely related to light, whereas promotion of hypocotyls growth by PwRFCP1 is independent on light. Under drought or salt treatment, overexpression of PwNAC2 in Arabidopsis showed more vigorous seed germination and significant tolerance for seedlings by ROS scavenging, reducing of membrane damage, slower water loss and increased stomatal closure. ABA or CBF-pathway marker genes were substantially higher in PwNAC2 transgenic Arabidopsis. Overexpression of PwRFCP1 promotes flowering in transgenic Arabidopsis, whereas PwNAC2 delayed flowering by altering the expression of FT, SOC1 and FLC. In addtioin, PwRFCP1 overexpression plants showed no higher tolerance to stress treatment than Col-0. Collectively, our results indicate that PwNAC2 enhanced plant tolerance to abiotic stress through multiple signaling pathways and participated in PwRFCP1-regulated flowering time.

Background:Cyrtotrachelus buqueti is a forest pest that severely damages bamboo shoots. Reducing the population of this insect involves complex mechanisms and is dependent on diverse gene expression influenced by environmental factors.Methods: In this study, samples from two regions of China, Muchuan in Sichuan Province and Chishui in Guizhou Province, were investigated through RNA-seq to explore the causes and molecular mechanisms underlying the population reduction of this species. Environmental factors, such as temperature, heavy metal content, and pH, may affect the reduced population of C. buqueti in Chishui.Results: Approximately 44 million high-quality reads were generated, and 94.2% of the data were mapped to the transcriptome. A total of 15,641 out of the 29,406 identified genes were predicted. Moreover, 348 genes were differentially expressed between the two groups of imagoes and included 77 upregulated and 271 downregulated UniGenes. The functional analysis showed that these genes were significantly enriched in ribosome and metabolic pathway categories. The candidate genes, which contributed to C. Buqueti reduction, included 41 genes involved in the ribosome constitution category, five genes in the one-carbon pool pathway by folate category, and five heat shock protein genes.Conclusions: Downregulation of these candidate genes seems to have impaired metabolic processes, such as protein, DNA, RNA, and purine synthesis, as well as carbon and folate metabolism, and finally resulted in the observed reduced population of C. buqueti. Furthermore, temperature, heavy metal content, and pH might influence the population by altering the expressions of genes involved in these metabolic processes.

In order to reduce the Cyrtotrachelus buqueti population, which is a serious pest in the bamboo industry, a range of approaches is required, which will be dependent on diverse gene expression influenced by environmental factors. In this study, samples from two regions of China, Muchuan in Sichuan Province and Chishui in Guizhou Province, were investigated through RNA-seq. Approximately 44 million high-quality reads were generated and 94.2% of the data was mapped to the transcriptome. A total of 15,641 out of the 29,406 identified genes were predicted. Moreover, 348 genes were differentially expressed between the two groups of imagoes (77 upregulated and 271 downregulated). The functional analysis showed that these genes were significantly enriched in the ribosome and metabolic pathway categories. The candidate genes contributing to the reduction in C. buqueti included 41 genes involved in the ribosome constitution category, five in the one‑carbon pool pathway by folate category, and five heat shock protein genes. The downregulation of these candidate genes seems to have impaired metabolic processes, such as protein, DNA, RNA, and purine synthesis, as well as carbon and folate metabolism, subsequently resulting in the observed population reduction of C. buqueti. Furthermore, temperature, heavy metal content, and pH might influence the population by altering the expressions of genes involved in these metabolic processes.

Nuclear factor Y (NF-Y) is a highly conserved transcription factor comprising NF-YA, NF-YB and NF-YC subunits. To date, the roles of NF-Y subunit in plant still remain elusive. In this study, a subunit NF-YB (PwNF-YB3), was isolated from Picea wilsonii Mast. and its role was studied. PwNF-YB3 transcript was detected in all vegetative and reproductive tissues with higher levels in stem and root and was greatly induced by salinity, heat and PEG but not by cold and ABA treatment. Over-expression of PwNF-YB3 in Arabidopsis showed a significant acceleration in the onset of flowering and resulted in more vigorous seed germination and significant tolerance for seedlings under salinity, drought and osmotic stress compared with wild type plants. Transcription levels of salinity-responsive gene (SOS3) and drought-induced gene (CDPK1) were substantially higher in transgenic Arabidopsis than in wild-type plants. Importantly, CBF pathway markers (COR15B, KIN1, LEA76), but not ABA pathway markers CBF4, were greatly induced under condition of drought. The nuclear localization showed that NF-YB3 acted as a transcription factor. Taken together, the data provide evidence that PwNF-YB3 positively confers significant tolerance to salt, osmotic and drought stress in transformed Arabidopsis plants probably through modulating gene regulation in CBF-dependent pathway.