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As an environmental stress factor, ultraviolet-B (UV-B) radiation directly affects insect growth, development, and reproduction. Heat shock protein 70s kDa (Hsp70s) plays an important role in the environmental adaptation of insects. To determine the role of MpHsp70s in the UV-B tolerance of Myzus persicae (Sulzer), we identified the complete complementary DNA sequences of seven MpHsp70s. They were found to be ubiquitously expressed during different developmental stages and were highly expressed in second-instar nymphs and wingless adults. The expression levels of the MpHsp70s were significantly upregulated when exposed to different durations of UV-B stress. Nanocarrier-mediated dsMpHsp70 suppressed the expression of the MpHsp70s and reduced the body length, weight, survival rate, and fecundity of M. persicae under UV-B exposure. When the combinational RNAi approach was adopted, the effects on the survival rate and fecundity were greater under UV-B stress, except for MpHsc70-4. These results suggest that MpHsp70s are essential for the resistance of M. persicae to UV-B stress.

In the passive positioning system, the traditional generalized cross-correlation algorithm estimates the effect under the influence of noise and reverberation, while the delay estimation algorithm after homomorphic filtering reduces the anti-reverb ability of the cross-correlation algorithm, but also reduces the cross-correlation of the signal, resulting in the decrease in the noise resistance of the cross-correlation algorithm. Based on this, the quadratic cross-correlation operation of the full-pass component of the signal is performed after homomorphic filtering to improve its noise immunity. In addition, the Introduction of Hilbert Difference sharpens the secondary cross-correlation peaks to make peak detection that reflects the time delay more accurate. Experimental simulation shows that the proposed method can effectively suppress the influence of noise and reverberation in non-stationary speech signals, and improve the performance of delay estimation.

Arma chinensis is an important predatory enemy of many agricultural and forest pests. Heat shock protein 70 (Hsp70) plays an essential role in insect adaptation to various stress factors. To explore the functions of Hsp70s in relation to thermal tolerance of A. chinensis, full-length cDNAs of six Hsp70 genes (AcHsp70Ba, AcHsp70-4, AcHsp68a, AcHsp68b, AcHsp70-2, and AcHsc70-4) were cloned. Their open reading frames (ORFs) were 1902, 2454, 1884, 1905, 1872, and 1947 bp, respectively. Developmental expression profiles showed that AcHsp70Ba, AcHsp70-4, and AcHsc70-4 were extremely highly expressed in adult stages. AcHsp68a and AcHsp70-2 showed the highest level of expression in nymph stages, and AcHsp68b was mainly expressed in male adults. Tissue distribution analysis demonstrated that the AcHsp70s were ubiquitously expressed but showing gene-specific and sex-driven patterns of expression. High temperature induced the expression of the six AcHsp70s. Among them, AcHsp70Ba, AcHsp70-4, AcHsp68a, and AcHsc70-4 were significantly induced at 38 °C for 6 h, while all six AcHsp70s were significantly induced at 38 °C for 24 h. There were differences in responses of the six AcHsp70s to low-temperature stress. The expressions of AcHsp70-4, AcHsp68a, and AcHsp68b in male adults were significantly repressed at 4 °C for 6 h, whereas AcHsp70Ba and AcHsp70-2 were significantly induced. The levels of AcHsp70Ba, AcHsp68b, and AcHsp70-2 in female adults were significantly repressed at 4 °C for 24 h, whereas AcHsc70-4 was significantly induced. These results suggested that AcHsp70s play important roles in various developmental stages and tissue function, and contribute to the tolerance of A. chinensis to extreme temperatures. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s12192-022-01303-y.

Ultraviolet A (UV-A) radiation is a significant environmental factor that causes photoreceptor damage, apoptosis, and oxidative stress in insects. Ostrinia furnacalis is an important pest of corn. To understand the adaptation mechanisms of insect response to UV-A exposure, this study revealed differentially expressed genes (DEGs) and differently expressed metabolites (DEMs) in O. furnacalis under UV-A exposure. Three complementary DNA libraries were constructed from O. furnacalis adult females (CK, UV1h, and UV2h), and 50,106 expressed genes were obtained through Illumina sequencing. Of these, 157 and 637 DEGs were detected in UV1h and UV2h after UV-A exposure for 1 and 2 h, respectively, compared to CK, with 103 and 444 upregulated and 54 and 193 downregulated genes, respectively. Forty four DEGs were detected in UV2h compared to UV1h. Comparative transcriptome analysis between UV-treated and control groups revealed signal transduction, detoxification and stress response, immune defense, and antioxidative system involvement. Metabolomics analysis showed that 181 (UV1h vs. CK), 111 (UV2h vs. CK), and 34 (UV2h vs. UV1h) DEMs were obtained in positive ion mode, while 135 (UV1h vs. CK), 93 (UV2h vs. CK), and 36 (UV2h vs. UV1h) DEMs were obtained in negative ion mode. Moreover, UV-A exposure disturbed amino acid, sugar, and lipid metabolism. These findings provide insight for further studies on how insects protect themselves under UV-A stress.

RNA silencing is a conserved mechanism in eukaryotic organisms to regulate gene expression. Argonaute (AGO), Dicer-like (DCL) and RNA-dependent RNA polymerase (RDR) proteins are critical components of RNA silencing, but how these gene families’ functions in sugarcane were largely unknown. Most stress-resistance genes in modern sugarcane cultivars (Saccharum spp.) were originated from wild species of Saccharum, for example S. spontaneum. Here, we used genome-wide analysis and a phylogenetic approach to identify four DCL, 21 AGO and 11 RDR genes in the S. spontaneum genome (termed SsDCL, SsAGO and SsRDR, respectively). Several genes, particularly some of the SsAGOs, appeared to have undergone tandem or segmental duplications events. RNA-sequencing data revealed that four SsAGO genes (SsAGO18c, SsAGO18b, SsAGO10e and SsAGO6b) and three SsRDR genes (SsRDR2b, SsRDR2d and SsRDR3) tended to have preferential expression in stem tissue, while SsRDR5 was preferentially expressed in leaves. qRT-PCR analysis showed that SsAGO10c, SsDCL2 and SsRDR6b expressions were strongly upregulated, whereas that of SsAGO18b, SsRDR1a, SsRDR2b/2d and SsRDR5 was significantly depressed in S. spontaneum plants exposed to PEG-induced dehydration stress or infected with Xanthomonas albilineans, causal agent of leaf scald disease of sugarcane, suggesting that these genes play important roles in responses of S. spontaneum to biotic and abiotic stresses.

A pink-pigmented, Gram-negative, rod-shaped, obligate aerobic bacterial strain, MIMD6T, was isolated from biological soil crusts in PR China. Cells grew at 20–37 °C (optimum, 30 °C), at pH 6–8 (optimum, pH 7) and with 0–1 % (w/v) NaCl (optimum, 0 %). Strain MIMD6T could use methanol or formate as a sole carbon source to grow, and carried methanol dehydrogenase genes mxaF and xoxF, supporting its methylotrophic metabolism. The respiratory quinone was ubiquinone Q-10, the major fatty acids were C18 : 1ω7c (87.3 %), and the major polar lipids were diphosphatidylglycerol, phosphatidylmonomethylethanolamine, phosphatidylethanolamine, phosphatidylglycerol, phosphatidylcholine, one unknown aminolipid and one unidentified glycolipid. The results of phylogenetic analyses based on the sequences of the 16S rRNA gene, seven housekeeping genes (dnaK, recA, rimO, rpIK, rpmG, rpsR and rpoB) and methanol dehydrogenase genes indicated that strain MIMD6T formed a phylogenetic linage with members of the genus Methylobacterium . Strain MIMD6T was most closely related to Methylobacterium isbiliense DSM 17168T and Methylobacterium nodulans LMG 21967T with 16S rRNA gene sequence similarities of 95.7 and 95.2 %, respectively. The genomic DNA G+C content calculated via draft genome sequencing was 73.0 mol%. The average nucleotide identity and digital DNA–DNA hybridization values between strain MIMD6T and the type strains of other Methylobacterium species were 70.7–82.0 and 24.6–30.0 %, respectively. Based on phenotypic, chemotaxonomic and phylogenetic characteristics, strain MIMD6T represents a novel species of the genus Methylobacterium , for which the name Methylobacterium crusticola sp. nov. is proposed. The type strain is MIMD6T (=KCTC 52305T=MCCC 1K01311T).

Reverse-transcription quantitative polymerase chain reaction (RT-qPCR) is commonly used to quantify gene expression. For normalization, the expression of each gene is compared with a reference "housekeeping" gene that is stably expressed under relevant stress. Unfortunately, there have been no reports on the stability of such reference genes under various treatments of the Spodoptera frugiperda. In this study, we used five tools (RefFinder, GeNorm, NormFinder, BestKeeper, and ΔCt methods) to evaluate the stability of 12 candidate reference genes (RPS18, β-tubulin, GAPDH, RPS7, RPS15, RPL7, RPL32, Actin-5C, EF1-α, EF1-γ, RPL27, and ACE) in different instars, tissues, and treatments (high and low temperature, UV-A, and emamectin benzoate). Several ribosomal proteins (RPS7, RPS15, RPL32, RPS18, and RPL7), GAPDH, Actin-5C, and β-tubulin, were relatively stable, suggesting that they are ideal housekeeping genes for various treatments. ACE was extremely unstable under various experimental treatments, rendering it unsuitable as an internal reference. This study identified the reference housekeeping genes stably expressed by S. frugiperda under different treatments, thus setting a foundation for further exploration of the physiological and biochemical mechanisms.

Spodoptera frugiperda (J. E. Smith) is a highly adaptable polyphagous migratory pest in tropical and subtropical regions. Small heat shock proteins (sHsps) are molecular chaperones that play important roles in the adaptation to various environment stressors. The present study aimed to clarify the response mechanisms of S. frugiperda to various environmental stressors. We obtained five S. furcifera sHsp genes (SfsHsp21.3, SfsHsp20, SfsHsp20.1, SfsHsp19.3, and SfsHsp29) via cloning. The putative proteins encoded by these genes contained a typical α-crystallin domain. The expression patterns of these genes during different developmental stages, in various tissues of male and female adults, as well as in response to extreme temperatures and UV-A stress were studied via real-time quantitative polymerase chain reaction. The results showed that the expression levels of all five SfsHsp genes differed among the developmental stages as well as among the different tissues of male and female adults. The expression levels of most SfsHsp genes under extreme temperatures and UV-A-induced stress were significantly upregulated in both male and female adults. In contrast, those of SfsHsp20.1 and SfsHsp19.3 were significantly downregulated under cold stress in male adults. Therefore, the different SfsHsp genes of S. frugiperda play unique regulatory roles during development as well as in response to various environmental stressors.

Sugarcane can suffer severe yield losses when affected by leaf scald, a disease caused by Xanthomonas albilineans. This bacterial pathogen colonizes the vascular system of sugarcane, which can result in reduced plant growth and plant death. In order to better understand the molecular mechanisms involved in the resistance of sugarcane to leaf scald, a comparative proteomic study was performed with two sugarcane cultivars inoculated with X. albilineans: one resistant (LCP 85-384) and one susceptible (ROC20) to leaf scald. The iTRAQ (isobaric tags for relative and absolute quantification) approach at 0 and 48 h post-inoculation (hpi) was used to identify and annotate differentially expressed proteins (DEPs). A total of 4295 proteins were associated with 1099 gene ontology (GO) terms by GO analysis. Among those, 285 were DEPs during X. albilineans infection in cultivars LCP 85-384 and ROC20. One hundred seventy-two DEPs were identified in resistant cultivar LCP 85-384, and 113 of these proteins were upregulated and 59 were downregulated. One hundred ninety-two DEPs were found in susceptible cultivar ROC20 and half of these (92) were upregulated, whereas the other half corresponded to downregulated proteins. The significantly upregulated DEPs in LCP 85-384 were involved in metabolic pathways, the biosynthesis of secondary metabolites, and the phenylpropanoid biosynthesis pathway. Additionally, the expression of seven candidate genes related to photosynthesis and glycolytic pathways, plant innate immune system, glycosylation process, plant cytochrome P450, and non-specific lipid transfer protein was verified based on transcription levels in sugarcane during infection by X. albilineans. Our findings shed new light on the differential expression of proteins in sugarcane cultivars in response to infection by X. albilineans. The identification of these genes provides important information for sugarcane variety improvement programs using molecular breeding strategies.

Sugarcane can suffer severe yield losses when affected by leaf scald, a disease caused by Xanthomonas albilineans. This bacterial pathogen colonizes the vascular system of sugarcane, which can result in reduced plant growth and plant death. In order to better understand the molecular mechanisms involved in the resistance of sugarcane to leaf scald, a comparative proteomic study was performed with two sugarcane cultivars inoculated with X. albilineans: one resistant (LCP 85-384) and one susceptible (ROC20) to leaf scald. The iTRAQ (isobaric tags for relative and absolute quantification) approach at 0 and 48 h post-inoculation (hpi) was used to identify and annotate differentially expressed proteins (DEPs). A total of 4295 proteins were associated with 1099 gene ontology (GO) terms by GO analysis. Among those, 285 were DEPs during X. albilineans infection in cultivars LCP 85-384 and ROC20. One hundred seventy-two DEPs were identified in resistant cultivar LCP 85-384, and 113 of these proteins were upregulated and 59 were downregulated. One hundred ninety-two DEPs were found in susceptible cultivar ROC20 and half of these (92) were upregulated, whereas the other half corresponded to downregulated proteins. The significantly upregulated DEPs in LCP 85-384 were involved in metabolic pathways, the biosynthesis of secondary metabolites, and the phenylpropanoid biosynthesis pathway. Additionally, the expression of seven candidate genes related to photosynthesis and glycolytic pathways, plant innate immune system, glycosylation process, plant cytochrome P450, and non-specific lipid transfer protein was verified based on transcription levels in sugarcane during infection by X. albilineans. Our findings shed new light on the differential expression of proteins in sugarcane cultivars in response to infection by X. albilineans. The identification of these genes provides important information for sugarcane variety improvement programs using molecular breeding strategies.

Ostrinia furnacalis, an important pest of corn, has substantial detrimental effects on corn production. The mitogen-activated protein kinase (MAPK) signaling pathway plays a pivotal role in an insect’s resistance to environmental stress. The expression levels of JNK and p38 have been well recorded in several insects under different environmental stressors, at different developmental stages, and in various tissue types; however, there is limited information on JNK and p38 in agricultural insects. To clarify the mechanism whereby O. furnacalis responds to environmental stress, we cloned JNK and p38 from O. furnacalis and subsequently named them OfJNK and Ofp38, respectively. Further, we examined the expression levels of OfJNK and Ofp38 under different environmental stressors. In this study, we obtained full-length sequences of OfJNK and Ofp38, and RT-qPCR results showed that these genes were expressed at all developmental stages, in various tissues (head, chest, abdomen, leg, wing, antennae, compound eye, midgut, and ovary) and under different environmental stressors (4°C and ultraviolet A treatment for 0, 30, 60, 90, and 120 min). The expression levels of OfJNK and Ofp38 were relatively higher in eggs and 3-day-old adult females than in other developmental stages. Moreover, the expression level of OfJNK was higher in the wings than in other tissues, whereas that of Ofp38 was significantly higher in the ovaries than in other tissues. OfJNK and Ofp38 showed high expression 90 min after being subjected to treatment at 4°C and ultraviolet A irradiation; the expression of Ofp38 peaked at 30 min, whereas that of OfJNK peaked at 60 min. These results indicate that O. furnacalis differs in terms of its response under different environmental stressors. In summary, our results will provide a foundation for additional research needed to determine the role of the MAPK signaling pathway and the underlying mechanisms by which it shows resistance to environmental stresses in insects.

International audience; Xanthomonas albilineans is the causal agent of leaf scald, a disease that can cause considerable damage to sugarcane industries. This study analysed the phylogenetic relationship of 14 samples of X. albilineans from China and 13 reference strains retrieved from the GenBank database by multilocus sequence analysis (MLSA). To reach this goal, five housekeeping genes of X. albilineans were amplified from diseased leaves and sequenced: gyrB, abc, rpoD, atpD and glnA. Based on the concatenated sequence of these genes (4473 nt), the 14 samples of X. albilineans from China had 99.9-100% sequence identity with one another and with five strains of the pathogen from the French West Indies and the USA (Florida). The 27 samples or strains of X. albilineans were distributed in two distinct clades in the MLSA-based phylogenetic tree. Clade 1 was formed by four strains of the pathogen from Fiji, Papua New Guinea and the USA. All the other strains from worldwide locations, including the 14 samples from China, were grouped in clade 2. This latter clade included all strains of the pathogen that were associated with outbreaks of leaf scald that have occurred over the last two decades, especially in the Caribbean islands and the USA. The very low diversity of X. albilineans in four Chinese provinces suggests recent spread of a single strain (from genetic group PFGE-B) of the leaf scald pathogen within China.

Sugarcane (Saccharum spp. hybrids) is a major source of sugar and renewable bioenergy crop worldwide and suffers serious yield losses due to many pathogen infections. Leaf scald caused by Xanthomonas albilineans is a major bacterial disease of sugarcane in most sugarcane-planting countries. The molecular mechanisms of resistance to leaf scald in this plant are, however, still unclear. We performed a comparative transcriptome analysis between resistant (LCP 85-384) and susceptible (ROC20) sugarcane cultivars infected by X. albilineans using the RNA-seq platform. 24 cDNA libraries were generated with RNA isolated at four time points (0, 24, 48, and 72 h post inoculation) from the two cultivars with three biological replicates. A total of 105,783 differentially expressed genes (DEGs) were identified in both cultivars and the most upregulated and downregulated DEGs were annotated for the processes of the metabolic and single-organism categories, respectively. Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis of the 7612 DEGs showed that plant&ndash, pathogen interaction, spliceosome, glutathione metabolism, protein processing in endoplasmic reticulum, and plant hormone signal transduction contributed to sugarcane&rsquo, s response to X. albilineans infection. Subsequently, relative expression levels of ten DEGs determined by quantitative reverse transcription-PCR (qRT-PCR), in addition to RNA-Seq data, indicated that different plant hormone (auxin and ethylene) signal transduction pathways play essential roles in sugarcane infected by X. albilineans. In conclusion, our results provide, for the first time, valuable information regarding the transcriptome changes in sugarcane in response to infection by X. albilineans, which contribute to the understanding of the molecular mechanisms underlying the interactions between sugarcane and this pathogen and provide important clues for further characterization of leaf scald resistance in sugarcane.

Elephant grass (Pennisetum purpureum) is an important fodder crop worldwide. Numerous plant pathogens have been found to infect this grass, which plays a major role as a reservoir for important pathogens of other grass crops including sugarcane. In this study, we collected 36 leaf samples and 108 juice samples from six symptomatic plants and 30 asymptomatic plants of elephant grass in Fuzhou, China for molecular detection of Xanthomonas albilineans, the putative causal agent of scald disease in grasses. X. albilineans was detected by PCR with specific primers XAF1/XAR1 in 25.0% (9/36) of the leaf and 5.6% (6/108) of the juice samples, while 55.6% (20/36) of the leaf and 81.5% (88/108) of the juice samples tested positive using a real-time quantitative PCR (qPCR) assay. PCR-amplified DNA fragments of two housekeeping genes, abc and gyrB, were cloned and sequenced from 15 positive samples, and the nucleotide sequences were 100% identical for both genes. Based on the concatenated sequences of the two genes (1512 nucleotides), phylogenetic analysis revealed that the X. albilineans strains infecting elephant grass clustered in the PFGE-B group with six reference strains from sugarcane that originated from Guadeloupe and Martinique (France), Florida (USA), and Fuzhou (China); All nucleotide sequences in this group were 100% identical. Additionally, two strains of X. albilineans isolated from elephant grass were identified as being highly pathogenic in young plants of elephant grass and sugarcane by artificial inoculation. The findings presented here attempt to address a gap in the literature, particularly with regard to molecular identification of X. albilineans naturally infecting elephant grass.

Grebes eat feathers, but the function of feathers in the alimentary tract and the digestion of feathers are poorly understood. In this article, we isolated Bacillus subtilis, a bacterium with strong feather-degrading ability, from the alimentary tract of grebes; we further purified a secretory keratinase with a molecular weight of 42KDa from B. subtilis. The optimal pH of the keratin-degrading reaction was 6.5, which exactly was the pH value in the alimentary tract of grebes. The feathers eaten by grebes can protect wall of the stomach. The feather net in the third chamber of the stomach could filter food and preventpetrous food such as bones from entering the alimentary track. Importantly, feathers could be digested by feather-degrading bacterium to supply the specific amino acids (cysteine and cystine) after fulfilling their protection function. It was suggested that the digestion of feathers in the alimentary tract of grebes was accomplished by the keratin-degrading bacteria. Key words: Grebes, feather-eating behavior, feather-degrading bacterium, keratinase

Helicoverpa armigera adults display a conspicuous positive phototactic behavior to light stimuli, and are especially sensitive to ultraviolet (UV) light. The effects of UV‐A (longwave) exposures on adult longevity and reproduction in H. armigera were investigated, as well as the development of the F1 generation. Paired adults were exposed to UV‐A for various time periods (0, 1, 5 and 9 h/day), until the end of adult life. The results showed that adult longevity decreased with increasing exposure time for both sexes, and a significant decrease was observed after exposure for 5 and 9 h/day. Fecundity increased when adults were exposed for 1 and 5 h/day, and a significant difference was observed in the 5 h/day group. Oviposition rates of females in all treatments were significantly higher than in the control. Exposure to UV‐A for longer periods (5 and 9 h/day) caused a decline in cumulative survival of F1 immature stages, but no significant differences were found in egg hatch, pupation and eclosion. The developmental periods of F1 larvae were significantly prolonged after exposure to UV‐A for 5 and 9 h/day. UV‐A radiation had no significant effects on F1 pupal period.

Ultraviolet (UV) light (blacklight), which emits UV in the range of 320–400 nm, has been used worldwide in light trapping of insect pests. To gain a better understanding of the response of Helicoverpa armigera adults to UV light irradiation, we carried out a comparative proteomic analysis. Three-day-old adults were exposed to UV light for 1 h. Total proteins were extracted and separated by two-dimensional gel electrophoresis. More than 1200 protein spots were reproducibly detected, including 12 that were more abundant and 21 less abundant. Mass spectrometry analysis and database searching helped us to identify 29 differentially abundant proteins. The identified proteins were categorized into several functional groups including signal transduction, RNA processing, protein processing, stress response, metabolisms, and cytoskeleton structure, etc. This study is the first analysis of differentially expressed proteins in phototactic insects under UV light irradiation conditions and gives new insights into the adaptation mechanisms responsive to UV light irradiation stress.

Ultraviolet (UV) light (blacklight), which emits UV in the range of 320-400 nm, has been used worldwide in light trapping of insect pests. In this article, we test the hypothesis that one of the effects of UV light irradiation is to increase oxidative stress on insects. The effects of UV light irradiation on total antioxidant capacity, malondialdehyde (MDA) and protein carbonyl contents and the activities of superoxide dismutase (SOD), catalase (CAT), peroxidases (POX) and glutathione-S-transferase (GST)were investigated in Helicoverpa armigera adults. The adults were exposed to UV light for various time periods (0, 30, 60 and 90 min). We found that exposure to UV light for 30 min resulted in increased total antioxidant capacity, protein carbonyl content and activities of SOD, CAT, POX and GST. When the exposure time lasted for 60 and 90 min, the protein carbonyl content and activities of CAT and GST remained significantly higher than the control. However, the antioxidant capacity and SOD activity returned to control levels, and POX activity decreased at 60 and 90 min. Our results confirm the hypothesis that UV light irradiation increases the level of oxidative stress in H. armigera adults.