Momordica charantia Is a Novel Host of 'Candidatus Phytoplasma malaysianum'-Related Strains Associated with Bitter Melon Stem Fasciation Disease in China.

Momordica charantia, also known as bitter melon, bitter gourd, and bitter squash, is a member of the Cucurbitaceae family and is widely grown in tropical and subtropical regions for its edible fruit and medicinal properties (Alves et al. 2017). In April 2022, bitter melon plants exhibiting stem fasciation and excessive tendril symptoms were observed in a 50-acre vegetable farm in Yijia Village, Weishan Yizu Huizu Autonomous County, Dali, Yunnan Province, China (Fig. 1). The farm primarily grew tomatoes, but around 400 bitter melon plants were planted in spots where tomatoes failed to establish. One plot had a 40% incidence rate, with four out of ten bitter melon plants showing symptoms. Scattered cases were observed in other plots, leading to an overall disease incidence rate of around 2% for the entire farm. Phytoplasma infection was suspected due to symptomatic plants growing in the same province as previously reported cases of phytoplasma diseases, such as happy tree (Camptotheca accuminata) witches'-broom disease, and the presence of phytoplasma-transmitting leafhoppers (Qiao et al. 2023). DNA was extracted from four symptomatic samples and two healthy controls collected from the abovementioned plot with a 40% disease incidence using Bioteke's Plant Genomic DNA Extraction Kit and then tested for phytoplasma infection. A nested PCR assay was conducted using primer pair P1/16S-SR followed by P1A/16S-SR to amplify the near full-length phytoplasma 16S rDNA (about 1.5kb) as previously described (Lee et al. 2004). None of the healthy controls tested positive for phytoplasma infection, while three out of four symptomatic plants showed positive results. The amplicons from the nested PCR were cloned into the pCRII-TOPO vector as previously described (Lee et al. 2004). The resulting clones were sequenced, and the representative sequence was deposited into GenBank (accession number PP489216). The iPhyClassifier (Zhao et al. 2009) was employed to determine the phytoplasma species and group/subgroup associated with the bitter melon stem fasciation (BMSF) disease. The results indicated that the diseased bitter melon plants were infected with a strain related to 'Candidatus Phytoplasma malaysianum' (EU371934), with a 98.07% sequence identity. The similarity coefficient was 1.00 compared to the reference strain of 16SrXXXII-D (GenBank accession: MW138004). The phytoplasma strain associated with BMSF disease was designated as BMSF1. In addition, the same DNA samples underwent further characterization of the BMSF strains. A nested PCR was conducted using primer pair rpL2F3/rpIR1A, followed by rp(III)-FN/rpIR1A to amplify a phytoplasma-specific rp gene segment (about 1.2 kb) (Martini et al. 2007; Davis et al. 2013). Three out of four samples tested positive, consistent with the 16S rRNA gene amplification results. Similarly, a primer pair L15F1/MapR1 followed by secYF1(III)/secYR1(III) was used to amplify a phytoplasma-specific partial spc operon (about 1.7 kb) that includes the complete secY gene and partial rpl15 and map genes, as previously described (Lee et al. 2010). The obtained rp and partial spc amplicons were cloned and sequenced (GenBank accession numbers PP464295 and PP464296). The rp and secY gene sequences were searched against the non-redundant nucleotide collection in the NCBI database using BLASTN. The top hit for the rp gene was 'Ca. Phytoplasma luffae' (CP054393), with 83.24% identity (1068/1283 base-matching). The top hit for the secY gene was also 'Ca. Phytoplasma luffae' (CP054393), with 72.53% identity (1294/1784 base-matching). The percent identity of the BMSF sequences compared to the top hit is low since no other group 16SrXXXII rp and secY gene sequences are available for comparison. A subgroup 16SrXXXII-D phytoplasma strain has been previously reported associated with Camptotheca acuminata witches'-broom (Qiao et al. 2023) and Trema tomentosa witches'-broom (Yu et al. 2021) in China. To our knowledge, bitter melon represents a new host of 'Candidatus Phytoplasma malaysianum'-related strains, and this is the first report of BMSF disease in China. The findings suggest that 'Candidatus Phytoplasma malaysianum'-related strains infect not only ornamental plants but also crops.

Metabolites from Lysobacter gummosus YMF3.00690 Against Meloidogyne javanica.

The strains in Lysobacter spp. have the potential to control plant-parasitic nematodes. In our experiment, L. gummosus YMF3.00690 showed antagonistic effects against plant root-knot nematode. Nine metabolites were isolated and identified from cultures of L. gummosus YMF3.00690, of which compound 1 was identified as a new metabolite tetrahydro-4,4,6-trimethyl-6-[(tetrahydro-6,6-dimethyl-2-oxo-4(1H)-pyrimidinylidene) methyl]-2(1H)-pyrimidinone. The activity assay showed that two compounds, 5-(hydroxymethyl)-1H-pyrrole-2-carbaldehyde (2) and 1H-pyrrole-2-carboxylic acid (3), had nematicidal activities against Meloidogyne javanica with mortalities of 69.93 and 90.54% at 400 ppm for 96 h, respectively. These two compounds were further tested for the inhibition activity of eggs hatching, and compound 3 showed a significant inhibition rate of 63.36% at 50 ppm for 48 h. In the chemotactic activity assay, three compounds (1 to 3) were found to have concentration-dependent chemotactic activity, of which compound 1 showed attractive activity. This experiment explored the active metabolites of L. gummosus YMF3.00690 against M. javanica and laid the foundation for biopesticide development.

First report of a new species, Chrysofolia galloides sp.nov., causing black spots on gallnuts of Rhus punjabensis var. sinica in China.

In June 2021 and 2022, 30-40% ensiform galls of Rhus punjabensis var. sinica (Diels) Rehd. et Wils. showing similar black spots were observed at a same woodland in Zhuyu town (E 107"42', N 32"10', altitude 560 m), Wanyuan, Southwest China. The lesions were usually dotted, rounded to irregular black or blackish brown spots, and scattered to gather into patches on the gall surfaces; the central areas of the lesions were often depressed. The infected galls often grow slowly or even fall off early. Fresh symptomatic galls were randomly collected in June 2021 (9 galls) and 2022 (13 galls). Tissues from the infected galls (ca. 3×5 mm) were surface-disinfected by 75% ethyl alcohol and 10% sodium hypochlorite (NaOCl), then plated on potato dextrose agar (PDA) at 25°C in the dark for six days. Nine isolates from different galls showed similar colony morphology. Similar dominant fungal colonies were isolated from 44.0% and 38.5% of the infected galls in 2021 and 2022, respectively. After sub-culturing of hyphal tips on PDA and oat meal agar (OA)，the colonies showed cottony-felty, annular, whitish to grey-brown after 10 days. Four isolates, IFRDCC1022 and IFRDCC1023 from 2021, and IFRDCC1024 and IFRDCC1025 from 2022 were randomly selected for molecular and morphological evaluations. Selected isolates were cultured on OA and incubated at 21°C at a 12 h/12 h day/night regime to induce sporulation (Jiang et al. 2020). Pycnidia (up to 500 µm diam.) developed within six days or longer. Conidiogenous cells lined the inner cavity of base, which were hyaline, occasionally brownish, ampulliform, 6-12 × 2-4.5 µm. Conidia were solitary, hyaline, guttulate, elliptic, sometimes subcylindric or ovoid, straight to curved, aseptate, (3.5-) 4-6.5 (-8) × 2-3.5 (-4) µm (n=60). Respective DNA fragments were amplified and sequenced with primers ITS1/ITS4 for ITS, LR0R/LR5 for LSU, EF1-728F (Carbone and Kohn 1999) /EF-2 (O'Donnell et al. 1998) for tef1-α, and Bt2a/ Bt2b for tub2 (Glass and Donaldson 1995). The obtained sequences were deposited in GenBank (accession Nos. ITS: OR363211 - OR363214, LSU: OR363215 - OR363218, tef1-α: OR344509 - OR344512, and tub2: OR344513 - OR344516). The morphological characteristics of the new isolates were consistent with the genus Chrysofolia (Crous et al. 2015). The conidiogenous cells (6-12 × 2-4.5 µm) are larger than those of C. colombiana Crous, Rodas & M.J. Wingf. 2015 (5-8 × 2-3 µm) and C. barringtoniae Suwannar., Kumla & Lumyong 2016 (3-7.5 × 2-3 µm), while shorter and wider than those of C. coriariae S.Y. Wang, Yong Wang bis, and Y. Li 2022 (5-20 × 1-3.5 µm). Maximum likelihood (ML), Maximum parsimony (MP) and Bayesian phylogenetic trees generated from the datasets all showed similar topologies, four strains formed a well-supported clade (BS = 99-100%, PP=0.99-1) in Chrysofolia genus, and clearly separated from the other three Chrysofolia spp. and clustered as sister to C. coriariae with high supported values (BS = 97-100%, PP=0.97-1). Based on morphological characteristics and DNA phylogeny, the new isolates were described as a new species, Chrysofolia galloides T. Ma & Z. X. Yang, sp. nov. (Mycobank: MB850312). The two isolates from 2021 (IFRDCC1022 and IFRDCC1023) were randomly selected for pathogenicity tests. Mycelial plugs (ca. 6×6 mm) of a two-week-old colony were placed onto the surface of wounded and unwounded healthy ensiform galls with six or seven replicates. Sterile PDA agar plugs were used as controls. The inoculated galls were incubated at 25°C in sterile plastic containers (21.4×14.0×5.0 cm) lined with wet filter paper for high humidity. The typical symptom appeared within 3 days on 83.3-100% wounded galls, while the unwounded galls and the controls remained asymptomatic. All wounded galls and 20.0-85.7% of unwounded galls showed symptoms within 5 days, while the controls remained asymptomatic. The fungus was reisolated from the lesions and showed identical morphology and 100% sequence similarity of ITS, LSU, tef1-α and tub2 with the initial isolates. No fungus was isolated from the controls. Neofusicoccum parvum is the first fungal pathogen demonstrated to induce brown spots on Chinese gallnuts (Ma and Yang 2022). Therefore, C. galloides is the second fungus confirmed to cause black spots lesions on gallnuts. These findings provide foundations for the comprehensive management of gall production, which have significant economical implication for Chinese gallnut production.

Comparison of multi-mode Hong-Ou-Mandel interference and multi-slit interference.

Hong-Ou-Mandel (HOM) interference of multi-mode frequency entangled states plays a crucial role in quantum metrology. However, as the number of modes increases, the HOM interference pattern becomes increasingly complex, making it challenging to comprehend intuitively. To overcome this problem, we present the theory and simulation of multi-mode-HOM interference (MM-HOMI) and compare it to multi-slit interference (MSI). We find that these two interferences have a strong mapping relationship and are determined by two factors: the envelope factor and the details factor. The envelope factor is contributed by the single-mode HOM interference (single-slit diffraction) for MM-HOMI (MSI). The details factor is given by sin (Nx)/sin (x) ([sin (Nv)/sin (v)]2) for MM-HOMI (MSI), where N is the mode (slit) number and x (v) is the phase spacing of two adjacent spectral modes (slits). As a potential application, we demonstrate that the square root of the maximal Fisher information in MM-HOMI increases linearly with the number of modes, indicating that MM-HOMI is a powerful tool for enhancing precision in time estimation. We also discuss multi-mode Mach-Zehnder interference, multi-mode NOON-state interference, and the extended Wiener-Khinchin theorem. This work may provide an intuitive understanding of MM-HOMI patterns and promote the application of MM-HOMI in quantum metrology.

Soil bacterium manipulates antifungal weapons by sensing intracellular type IVA secretion system effectors of a competitor.

Soil beneficial bacteria can effectively inhibit bacterial pathogens by assembling contact-dependent killing weapons, such as the type IVA secretion system (T4ASS). It's not clear whether these antibacterial weapons are involved in biotrophic microbial interactions in soil. Here we showed that an antifungal antibiotic 2,4-DAPG production of the soil bacterium, Pseudomonas protegens can be triggered by another soil bacterium, Lysobacter enzymogenes, via T4ASS by co-culturing on agar plates to mimic cell-to-cell contact. We demonstrated that the induced 2,4-DAPG production of P. protegens is achieved by intracellular detection of the T4ASS effector protein Le1519 translocated from L. enzymogenes. We defined Le1519 as LtaE (Lysobacter T4E triggering antifungal effects), which specifically stimulates the expression of 2,4-DAPG biosynthesis genes in P. protegens, thereby protecting soybean seedlings from infection by the fungus Rhizoctonia solani. We further found that LtaE directly bound to PhlF, a pathway-specific transcriptional repressor of the 2,4-DAPG biosynthesis, then activated the 2,4-DAPG production. Our results highlight a novel pattern of microbial interspecies and interkingdom interactions, providing a unique case for expanding the diversity of soil microbial interactions.

Spatial-spectral mapping to prepare frequency entangled qudits.

Entangled qudits, the high-dimensional entangled states, play an important role in the study of quantum information. How to prepare entangled qudits in an efficient and easy-to-operate manner is still a challenge in quantum technology. Here, we demonstrate a method to engineer frequency entangled qudits in a spontaneous parametric downconversion process. The proposal employs an angle-dependent phase-matching condition in a nonlinear crystal, which forms a classical-quantum mapping between the spatial (pump) and spectral (biphotons) degrees of freedom. In particular, the pump profile is separated into several bins in the spatial domain, and thus shapes the down-converted biphotons into discrete frequency modes in the joint spectral space. Our approach provides a feasible and efficient method to prepare a high-dimensional frequency entangled state. As an experimental demonstration, we generate a three-dimensional entangled state by using a homemade variable slit mask.

Comprehensive analysis of the biological functions of endoplasmic reticulum stress in prostate cancer.

Introduction: Endoplasmic reticulum stress (ERS) has sizeable affect on cancer proliferation, metastasis, immunotherapy and chemoradiotherapy resistance. However, the effect of ERS on the biochemical recurrence (BCR) of prostate cancer patients remains elusive. Here, we generated an ERS-related genes risk signature to evaluate the physiological function of ERS in PCa with BCR. Methods: We collected the ERS-related genes from the GeneCards. The edgeR package was used to screen the differential ERS-related genes in PCa from TCGA datasets. ERS-related gene risk signature was then established using LASSO and multivariate Cox regression models and validated by GEO data sets. Nomogram was developed to assess BCR-free survival possibility. Meanwhile, the correlations between ERS-related signature, gene mutations, drug sensitivity and tumor microenvironment were also investigated. Results: We obtained an ERS risk signature consisting of five genes (AFP, COL10A1, DNAJB1, EGF and PTGS2). Kaplan Meier survival analysis and ROC Curve analysis indicated that the high risk score of ERS-related gene signature was associated with poor BCR-free prognosis in PCa patients. Besides, immune cell infiltration and immune checkpoint expression levels differed between high- and low-risk scoring subgroups. Moreover, drug sensitivity analyzed indicated that high-risk score group may be involved in apoptosis pathway. Discussion: This study comprehensively analyzed the characteristics of ERS related genes in PCa, and created a five-gene signature, which could effectively predict the BCR time of PCa patients. Targeting ERS related genes and pathways may provide potential guidance for the treatment of PCa.

Lysobacter enzymogenes prevents Phytophthora infection by inhibiting pathogen growth and eliciting plant immune responses.

The Phytophthora pathogen causes enormous damage to important agricultural plants. This group of filamentous pathogens is phylogenetically distant from fungi, making them difficult to control by most chemical fungicides. Lysobacter enzymogenes OH11 (OH11) is a biocontrol bacterium that secretes HSAF (Heat-Stable Antifungal Factor) as a broad-spectrum antifungal weapon. Here, we showed that OH11 could also control a variety of plant Phytophthora diseases caused by three major oomycetes (P. sojae, P. capsici and P. infestans). We provided abundant evidence to prove that OH11 protected host plants from Phytophthora pathogen infection by inhibiting mycelial growth, digesting cysts, suppressing cyst germination, and eliciting plant immune responses. Interestingly, the former two processes required the presence of HSAF, while the latter two did not. This suggested that L. enzymogenes could prevent Phytophthora infection via multiple previously unknown mechanisms. Therefore, this study showed that L. enzymogenes could serve as a promising alternative resource for promoting plant resistance to multiple Phytophthora pathogens.

Candidate genes potentially involved in molting and body size reduction in the male of the horned gall aphid, Schlechtendalia chinensis.

In general, insects grow (increase in body size) through molting. To the opposite, the body size of the males of the horned gall aphid, Schlechtendalia chinensis, gets smaller after molting and as they age. To understand the molecular bases of this rare phenomenon, transcriptomes were generated from 1-5 days old male and the data were analyzed via a weighted gene co-expression network analysis (WGCNA). A total of 15 partitioned modules with different topological overlaps were obtained, and four modules were identified as highly significant for male body length (p < 0.05). Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis suggested that a portion of genes in the four modules are likely involved in autophagy and apoptosis. In addition, a total of 40 hub genes were obtained in the four modules, and among them eight genes were highly expressed in males compared to individuals of other generations of S. chinensis. These eight genes were associated with autophagy and apoptosis. Our results reveal the unique negative growth phenomenon in male S. chinensis after molting, and also suggest that the male S. chinensis with no ability to feed probably decompose their own substances via autophagy and apoptosis to provide energy for life activities such as germ cell development.

Loss of Flagella-Related Genes Enables a Nonflagellated, Fungal-Predating Bacterium To Strengthen the Synthesis of an Antifungal Weapon.

Loss of flagellar genes causes a nonmotile phenotype. The genus Lysobacter consists of numerous environmentally ubiquitous, nonflagellated bacteria, including Lysobacter enzymogenes, an antifungal bacterium that is beneficial to plants. L. enzymogenes still has many flagellar genes on its genome, although this bacterium does not engage in flagella-driven motility. Here, we report that loss of certain flagellar genes allows L. enzymogenes to strengthen its evolutionarily gained capacity in fungal killing. To clarify why this bacterium loses flagellar genes during the evolutionary process, we cloned several representative flagellar genes from Xanthomonas oryzae, a flagellated, phylogenetically related species of Lysobacter, and introduced them individually into L. enzymogenes to mimic genomic reacquisition of lost flagellar genes. Heterogeneous expression of the three X. oryzae flagellar structural genes (Xo-motA, Xo-motB, Xo-fliE) and one flagellar regulatory gene (Xo-fleQ) remarkably weakened the bacterial capacity to kill fungal pathogens by impairing the synthesis of an antifungal weapon, known as the heat-stable antifungal factor (HSAF). We further investigated the underlying mechanism by selecting Xo-FleQ as the representative because it is a master transcription factor responsible for flagellar gene expression. Xo-FleQ inhibited the transcription of operon genes responsible for HSAF synthesis via direct binding of Xo-FleQ to the promoter region, thereby decreasing HSAF biosynthesis by L. enzymogenes. These observations suggest a possible genome and function coevolution event, in which an antifungal bacterium deletes certain flagellar genes in order to enhance its ability to kill fungi. IMPORTANCE It is generally recognized that flagellar genes are commonly responsible for the flagella-driven bacterial motility. Thus, finding nonflagellated bacteria partially or fully lost flagellar genes is not a surprise. However, the present study provides new insights into this common idea. We found that loss of either certain flagellar structural or regulatory genes (such as motA, motB, fliE, and fleQ) allows a nonflagellated, antifungal bacterium (L. enzymogenes) to stimulate its fungal-killing capacity, outlining a genome-function coevolution event, where an antifungal bacterium "smartly" designed its genome to "delete" crucial flagellar genes to coordinate flagellar loss and fungal predation. This unusual finding might trigger bacteriologists to reconsider previously ignored functions of the lost flagellar genes in any nonflagellated, pathogenic, or beneficial bacteria.

Identification of atypical T4SS effector proteins mediating bacterial defense.

To remain competitive, proteobacteria use various contact-dependent weapon systems to defend against microbial competitors. The bacterial-killing type IV secretion system (T4SS) is one such powerful weapon. It commonly controls the killing/competition between species by secreting the lethal T4SS effector (T4E) proteins carrying conserved XVIPCD domains into competing cells. In this study, we sought knowledge to understand whether the bacterial-killing T4SS-producing bacteria encode T4E-like proteins and further explore their biological functions. To achieve this, we designed a T4E-guided approach to discover T4E-like proteins that are designated as atypical T4Es. Initially, this approach required scientists to perform simple BlastP search to identify T4E homologs that lack the XVIPCD domain in the genomes of T4SS-producing bacteria. These homologous genes were then screened in Escherichia coli to identify antibacterial candidates (atypical T4Es) and their neighboring detoxification proteins, followed by testing their gene cotranscription and validating their physical interactions. Using this approach, we did discover two atypical T4E proteins from the plant-beneficial Lysobacter enzymogenes and the phytopathogen Xanthomonas citri. We also provided substantial evidence to show that the atypical T4E protein Le1637-mediated bacterial defense in interspecies interactions between L. enzymogenes and its competitors. Therefore, the newly designed T4E-guided approach holds promise for detecting functional atypical T4E proteins in bacterial cells.

A New Genus and Species of Gall-Forming Fordini (Hemiptera: Aphididae) on Rhus wilsonii Hemsl. from Yunnan, China.

A new species of gall-forming aphid from China, Qiao jinshaensis gen. et sp. nov., is described from Rhus wilsonii Hemsl. Morphological identification and molecular analyses both support the establishment of a new genus. A diagnosis combining morphological and molecular characters from alate viviparae is provided and specimen metadata are published in an open-access and machine-readable format.

Docosahexaenoic acid production of the marine microalga Isochrysis galbana cultivated on renewable substrates from food processing waste under CO2 enrichment.

Leftover dough is a starch-rich food processing waste of Chinese steamed bread. Leftover dough hydrolysates enriched with glucose and amino acids were used to cultivate the marine microalga Isochrysis galbana to produce docosahexaenoic acid (DHA) under CO2 enrichment. Isochrysis galbana could use mixed carbon sources (CO2, glucose, and amino acids) synchronously to grow and accumulate DHA. Cell growth, the uptake of glucose and amino acids, and DHA production were significantly affected by CO2 enrichment. The maximum biomass concentration of 3.85 g L-1 was achieved with 3 % CO2. And the maximum DHA yield was 65.5 mg L-1 d-1. To enhance DHA production, a two-stage cultivation strategy was successfully developed by this work. The maximum DHA yield of the two-stage culture was elevated by 2.3-fold. It is feasible to produce DHA by Isochrysis galbana using leftover dough under CO2 enrichment.

Chromosome-level genome assembly for the horned-gall aphid provides insights into interactions between gall-making insect and its host plant.

The aphid Schlechtendalia chinensis is an economically important insect that can induce horned galls, which are valuable for the medicinal and chemical industries. Up to now, more than twenty aphid genomes have been reported. Most of the sequenced genomes are derived from free-living aphids. Here, we generated a high-quality genome assembly from a galling aphid. The final genome assembly is 271.52 Mb, representing one of the smallest sequenced genomes of aphids. The genome assembly is based on contig and scaffold N50 values of the genome sequence are 3.77 Mb and 20.41 Mb, respectively. Nine-seven percent of the assembled sequences was anchored onto 13 chromosomes. Based on BUSCO analysis, the assembly involved 96.9% of conserved arthropod and 98.5% of the conserved Hemiptera single-copy orthologous genes. A total of 14,089 protein-coding genes were predicted. Phylogenetic analysis revealed that S. chinensis diverged from the common ancestor of Eriosoma lanigerum approximately 57 million years ago (MYA). In addition, 35 genes encoding salivary gland proteins showed differentially when S. chinensis forms a gall, suggesting they have potential roles in gall formation and plant defense suppression. Taken together, this high-quality S. chinensis genome assembly and annotation provide a solid genetic foundation for future research to reveal the mechanism of gall formation and to explore the interaction between aphids and their host plants.

Molecular and Histologic Adaptation of Horned Gall Induced by the Aphid Schlechtendalia chinensis (Pemphigidae).

Chinese galls are the result of hyperplasia in host plants induced by aphids. The metabolism and gene expression of these galls are modified to accommodate the aphids. Here, we highlight the molecular and histologic features of horned galls according to transcriptome and anatomical structures. In primary pathways, genes were found to be unevenly shifted and selectively expressed in the galls and leaves near the galls (LNG). Pathways for amino acid synthesis and degradation were also unevenly shifted, favoring enhanced accumulation of essential amino acids in galls for aphids. Although galls enhanced the biosynthesis of glucose, which is directly available to aphids, glucose content in the gall tissues was lower due to the feeding of aphids. Pathways of gall growth were up-regulated to provide enough space for aphids. In addition, the horned gall has specialized branched schizogenous ducts and expanded xylem in the stalk, which provide a broader feeding surface for aphids and improve the efficiency of transportation and nutrient exchange. Notably, the gene expression in the LNG showed a similar pattern to that of the galls, but on a smaller scale. We suppose the aphids manipulate galls to their advantage, and galls lessen competition by functioning as a medium between the aphids and their host plants.

Wax glands of the horned gall aphid, Schlechtendalia chinensis, at different stages.

The horned gall aphid, Schlechtendalia chinensis, inhabits the productive species of Chinese gallnuts, which have economic value. Aphid wax glands are crucial for the survival of the insects, since the secreted waterproofing wax is important to protect the aphids from predators, pathogens and honeydew contamination. In this study, we investigated the structure of wax glands and their role in different aphid stages using light and electron microscopy. Our results show that aphids of all stages except the newly hatched fundatrix possess six parallel dorsal lines and have a total of 56 wax gland plates. Although no wax glands occur on the dorsum of the newly hatched fundatrix (first instar), the glands do appear once a fundatrix enters the second instar. The wax gland plate is composed of 2-22 polygonal depressions, each of which corresponds to a secretory cell covered by cuticle. The wax glands of this aphid belong to the class 1 glands, which are formed by epidermal secretory cells. The structure of the wax glands varies in the different stages and these changes may be adaptive to the changeable microenvironments in which the aphids live.

A Complex Nutrient Exchange Between a Gall-Forming Aphid and Its Plant Host.

It has been a long-standing question as to whether the interaction between gall-forming insects and their host plants is merely parasitic or whether it may also benefit the host. On its host Rhus chinensis, the aphid Schlechtendalia chinensis induces the formation of closed galls, referred to as horned galls. Typically, mature aphid populations comprise thousands of individuals, which is sufficient to cause the accumulation of high CO2 levels in galls (on average 8-fold higher and up to 16 times than atmospheric levels). Large aphid populations also excrete significant amounts of honeydew, a waste product high in sugars. Based on 13C isotope tracing and genomic analyses, we showed that aphid-derived carbon found in CO2 and honeydew was recycled in gall tissues via photosynthesis and glycometabolism. These results indicated that the aphid-gall system evolved in a manner that allowed nutrient recycling, where the gall provides nutrients to the growing aphid population, and in turn, aphid-derived carbon metabolites provide a resource for the growth of the gall. The metabolic efficiency of this self-circulating system indicates that the input needed from the host plant to maintain aphid population growth less than previously thought and possibly minimal. Aside from the recycling of nutrients, we also found that gall metabolites were transported to other parts of the host plant and is particularly beneficial for leaves growing adjacent to the gall. Taken together, galls in the S. chinensis-Rhus chinensis system are highly specialized structures that serve as a metabolic and nutrient exchange hub that benefits both the aphid and its host plant. As such, host plants provide both shelter and nutrients to protect and sustain aphid populations, and in return, aphid-derived metabolites are channeled back to the host plant and thus provide a certain degree of "metabolic compensation" for their caloric and structural needs.

Molecular detection and phylogenetic analyses of Wolbachia in natural populations of nine galling Aphid species.

Wolbachia is one of the most abundant facultative intracellular symbionts in arthropods. It alters host biology in diverse ways, including the induction of reproductive manipulation, association of nutrient supplier and protection against pathogens. Aphids are a group of insects which exhibit interesting biological characteristics such as complex life cycles, alteration of sexual and asexual reproduction and shifts between two different hosts. Wolbachia is widely present in many orders of insects, but so far limited studies on Wolbachia in aphids have been carried out. Galling aphids are a group of aphids that induce galls on their primary host plants at specific life stage. In this study, 15 natural populations representing nine galling aphid species were analyzed for the presence of Wolbachia using species-specific primer pairs. Wolbachia presence in galling aphids was quite low and varied significantly among aphid populations. Only three of the 15 populations we analyzed had detectable Wolbachia and the overall infection rate was 20%. Two Wolbachia strains, O and B, were identified from the galling aphids Kaburagia rhusicola and Schlechtendalia chinensis. Strain O was for the first time to be found in aphids, and it is likely involved with the life stages of galling aphids living in closed microenvironments with specific survival strategies that are different from free-living aphids.

Microenvironmental analysis of two alternating hosts and their impact on the ecological adaptation of the horned sumac gall aphid Schlechtendalia chinensis (Hemiptera, Pemphiginae).

The aphid Schlechtendalia chinensis(Bell) induces horned galls on their primary host Rhus chinensis(Mill). These galls serve as closed habitats to support thousands of aphids per gall. Ecological parameters inside a gall are unknown. In this study, we showed that the microclimate inside galls was reltively stable, with nearly 100% humidity and 30-50 lux light regardless of outside environmental conditions. Gall-residing aphids produce waste gas and honeydew. A gall contained 26 organic volatiles inside with acetic acid as the largest component. Honeydew is rich in sugars and may provide nutrients for microbial growth. However, no evidence for pathogenic microorganisms was found inside a gall. The acidic environment in a gall may curb microbial growth. On the secondary host, the moss Plagiomnium maximoviczii (Lindb.) T. J. Kop., the microclimate is unstable and humidity fluctuated at 45~100%, while light ranged from 150 to 500 lux on different environmental conditions. Aphid alternated in two different habitats, the gall generation increased from a single fundatrix to thousands of aphids, however, survival rate of the moss generation is less 3%. A comparison of the environmental traits between gall and moss revealed that a stable habitat with dark and moist is advantageous for aphid reproduction.