Stem Gall Research Articles

Allelopathic potential of the extracts of non-galled stems and globoid stem galls of Eremanthus erythropappus (DC) McLeish (Asteraceae)

Eremanthus erythropappus (DC) McLeisch (Asteraceae), commonly known as “candeia”, is a native species of Minas Gerais state, Brazil, frequently used in medicine as an anti-inflammatory and antimicrobial agent. Eremanthus erythropappus hosts six different gall morphotypes, whose associated inducers manipulate plant cells and tissues and stimulate the neo-synthesis, maintenance, or inhibition of both primary and secondary metabolites on their host plant organs. Based on the premise that galls can potentialize the chemical composition of their associated host plants, our study investigated the allelopathic potential of methanolic extracts of E. erythropappus non-galled stems and globoid stem galls on Lactuca sativa seeds. We also studied the anatomical alterations induced on lettuce plantlets submitted to the methanolic extracts to describe diagnostic features related to the allelopathic effect. Five pentacyclic triterpenes constituted the major class of the identified compounds, followed by volatile oils, alkane hydrocarbons, alkanes, and ketones. The germination rates were statistically different between the treatments, and among the treatments, and the controls (water and methanol). The pentacyclic triterpenes of the extracts of the non-galled stems and the stem galls have a powerful allelopathic effect on the germination of L. sativa; a higher effect than that of the sesquiterpenes of the essential oils previously described for the leaf chemical compounds. The galling Neolasioptera sp. activity on E. erythropappus stems elicited the synthesis and accumulation of new chemical compounds, two triterpenes (ɤ-taraxasterol, and β-amyrone) and one alkane (tricosane), and inhibited the synthesis of compounds previously related to extracts of E. erythropappus stems, i.e., two triterpenes (A-neooleana-3(5),12-diene, and lupenone) and one ketone (2(1H)naphthalenone). These extracts altered the differentiation of root parenchyma cells of L. sativa germinated plantlets, but our premise was not corroborated as the galling activity did not potentialize the allelopathic effects.

Phenolic substances and cyanogenesis in galled and non-galled tissue of the fern species Microgramma vacciniifolia.

Galls, neo-formed plant structures that can occur in different organs, are generated by species-specific interaction with an inducing organism. Inducers manipulate the metabolism of its host. Microgramma vacciniifolia (Langsd. & Fisch.) Copel. is a Neotropical epiphytic fern that hosted two stem galls, one induced by a midge species (Diptera) and other by a micromoth species (Lepidoptera). The aim of this study was to evaluate the impact of these two gall-inducing insects on the biochemistry of phenolic acids and the cyanogenesis in galls, stems and leaves of M. vacciniifolia. High performance liquid chromatography (HPLC) indicated a total of 14 phenol derivatives, including caffeic and coumaric acid. Principal Coordinates Analysis (PCoA) of the phenolic substances indicated three groups consisting (1) non-galled stems and micromoth-induced galls; (2) midge-induced galls; (3) midge-induced galls with parasitoids. Regarding the frequency of cyanogenesis assessed by the picrate paper test, the chi-squared test showed significant difference between fertile leaves (8.3%), sterile leaves (27.7%), non-galled stems (0%) and galls. Among galls, only the midge-induced galls analyzed were cyanogenic (15%). Our results indicated that the different gall-inducers (midge and micromoth) promote species-specific alterations to the phenolic substance composition of the host fern.

Characterization of Protomyces macrosporus causing stem gall of coriander (Coriandrum sativum)

Coriander (Coriandrum sativum L.) is an annual herbaceous plant and suffers from different fungal, bacterial andviral diseases of which stem gall caused by Protomyces macrospores is one among them. The disease appears in theform of tumour like swellings of leaf veins, leaf stalks, peduncles, stems and on fruits. The test pathogen was isolatedfrom infected stem and seeds and pure culture of the fungus was obtained on potato dextrose agar enriched with yeastextract medium. The colour of colony was creamy white initially which later turned light brown. Morphologicalcharacters comprising chlamydospores were studied which were yellowish brown, spherical or globose to oval,single-celled, smooth and measured 40-80 μ in diameter. For molecular characterization, genomic DNA was isolatedusing standard procedures and a region of the nuclear rDNA gene containing the internal transcribed spacer regionswas amplified from the genomic DNA. Phylogenetic tree showed that isolated strain A clustered close to Protomycesinouyei with 62% similarity only. Based on morphological characteristics, the isolated fungus was identified asProtomyces macrosporus but on the ITS sequences comparisons, strain A was similar to Protomyces sp. Pathogenicitytests showed that crushed powder of infected seed added to soil was better in disease development over mycelialsuspension and the symptoms of the disease appeared in 42.5 days.

Significance of Sowing Dates and Meteorological Parameters on Severity of Stem Gall of Coriander Caused by Protomyces macrosporus

Background: Coriander (Coriandrum sativum L.) belongs to family Apiaceae is generally grown in winter season as a main crop in India. Stem gall of coriander caused by Protomyces macrosporus L. is a serious disease damaging all aerial plant parts. Under favourable ecological conditions, the disease may lead losses to the extent of 100 per cent therefore it is necessary to investigate the epidemiology of the disease to devise suitable remedial measures Methods: The field experiment was conducted during Kharif season of 2018 with two varieties to study the effect of different meteorological parameters on stem gall of coriander at different sowing dates (1st week of November to 1st week of December). The stem gall severity was recorded at weekly intervals from the start of its incidence. Result: The disease severity was lowest (5.42%) in the variety DH-36 sown in 3rd week of November and maximum disease severity (11.88%) was observed in variety DH-228 sown in 1st week of December. The quantitative relationship between the disease severity and weather variables at different dates of sowing for two varieties was obtained by performing correlation analysis. The temperature (maximum and minimum) and sunshine hours had positive correlation with per cent disease intensity, while relative humidity (morning and evening) and remaining weather parameters were non-significant at each dates of sowing but correlated with the disease intensity.

Hyperspectral Imaging Combined with Machine Learning for the Detection of Fusiform Rust Disease Incidence in Loblolly Pine Seedlings

Loblolly pine is an economically important timber species in the United States, with almost 1 billion seedlings produced annually. The most significant disease affecting this species is fusiform rust, caused by Cronartium quercuum f. sp. fusiforme. Testing for disease resistance in the greenhouse involves artificial inoculation of seedlings followed by visual inspection for disease incidence. An automated, high-throughput phenotyping method could improve both the efficiency and accuracy of the disease screening process. This study investigates the use of hyperspectral imaging for the detection of diseased seedlings. A nursery trial comprising families with known in-field rust resistance data was conducted, and the seedlings were artificially inoculated with fungal spores. Hyperspectral images in the visible and near-infrared region (400–1000 nm) were collected six months after inoculation. The disease incidence was scored with traditional methods based on the presence or absence of visible stem galls. The seedlings were segmented from the background by thresholding normalized difference vegetation index (NDVI) images, and the delineation of individual seedlings was achieved through object detection using the Faster RCNN model. Plant parts were subsequently segmented using the DeepLabv3+ model. The trained DeepLabv3+ model for semantic segmentation achieved a pixel accuracy of 0.76 and a mean Intersection over Union (mIoU) of 0.62. Crown pixels were segmented using geometric features. Support vector machine discrimination models were built for classifying the plants into diseased and non-diseased classes based on spectral data, and balanced accuracy values were calculated for the comparison of model performance. Averaged spectra from the whole plant (balanced accuracy = 61%), the crown (61%), the top half of the stem (77%), and the bottom half of the stem (62%) were used. A classification model built using the spectral data from the top half of the stem was found to be the most accurate, and resulted in an area under the receiver operating characteristic curve (AUC) of 0.83.

First report of stem gall in papaya caused by Pantoea dispersa

Callus like galls were observed inside the stem of more than 5-year old papaya trees in Kerala, India. The bacterium Pantoea dispersa and the fungus Fusarium spinosum were isolated from these galls. Identity of the fungus was confirmed by sequencing and analysis of rDNA region, EFα gene and phylogenetic and barcode analyses. Bacterial identity was confirmed by analysis of rDNA region. Pathogenicity tests with a combination of the fungus and bacterium and bacterium alone, resulted in gall formation. Individual inoculation of F. spinosum did not result in gall. Only P. dispersa was re-isolated from the galls, indicating its etiological role. Supplemental data for this article is available online at https://doi.org/10.1080/03235408.2021.1974686 .

Development and characterization of genic SSR-FDM for stem gall disease resistance in coriander (Coriandrum sativum L.) and its cross species transferability.

Coriander (Coriandrum sativum L.) is well known vegetable and spice crop grown globally for its leaves and seeds. Stem gall (Protomyces macrosporus L.) is a fungal disease affecting its quality and yield. However, no information is available on SSR markers linked to disease resistance in coriander. Hence, development of co-dominant genetic markers is prerequisite for disease investigations in coriander. In-house stem gall resistance and susceptible cultivars transcriptome data were utilized. Totally, 59,933 and 56,861 transcripts were examined, 9141 and 8346 Simple Sequence Repeats (SSR) were identified and the most abundant type was the tri, followed by di, tetra, penta and hexa nucleotide repeats. A total of ten selected SSR-Functional Domain Markers (FDM) were developed based on functional annotation terms associated with pathogen response and validated among ten coriander cultivars and their transferability was examined in five fennel (Foeniculum vulgare L.) cultivars. Nine primer pairs resulted from amplified bands. Marker ACorSGD-1 shown monomorphic bands among coriander genotypes except Acr-1 showed heterologouse and multiple bands in fennel cultivars. Markers ACorSGD-4, 5, 7 and 9 shown presence in resistant cultivars and absence of bands among susceptible cultivars of coriander and thus, considered to be the candidate markers for disease screening. Marker ACorSGD-6 shown monomorphic bands among coriander. Markers ACorSGD-1, 2, 3, and 5 shown transferability among fennel cultivars. A total of 136 alleles in coriander and fennel were produced. Using UPGMA clustering method a dendrogram was generated and cultivars were grouped into two separate clusters with coriander and fennel. Identified and developed SSR-FDM markers are useful for linkage mapping for disease resistant in coriander.

First Report of Gymnosporangium clavipes Causing Stem Galls on Crataegus marshallii in Florida, U.S.A.

The parsley hawthorn Crataegus marshallii Eggleston (Rosaceae, Maloideae) is a small tree native to the southeastern United States and is a less common but prized ornamental, known for its bright fruit and flaking bark. In March of 2020, a stem gall with visible aecia on the lower surface was observed on an ornamental parsley hawthorn in Gainesville, Alachua County, Florida, U.S.A. The affected stem was collected and brought to the Florida Department of Agriculture and Consumer Services – Division of Plant Industry headquarters in Gainesville for identification (FDACS-DPI, 2020-104160). Aecia tubular, whitish, occurred on twigs (caulicolous), producing terminal swellings, mostly short and up to 1.5 mm high with white peridium containing bright orange spores in masses. Aeciospores were semigloboid to globoid, with bright orange contents, 26 to 34 µm in diameter (n = 20)—color and size are considered diagnostic features (EPPO 2006)—wall was densely verrucose, hyaline, and 2 to 4 µm thick. The morphological characteristics are consistent with those of Gymnosporangium clavipes Cooke & Peck (Pucciniaceae, Pucciniomycotina) described by Kern (1973). A voucher was deposited in the Florida Department of Agriculture and Consumer Services DPI Herbarium (PIHG, specimen number 14893). The morphological identification was confirmed by molecular identification. Following DNA extraction, we performed PCR amplification and Sanger sequencing of the internal transcribed spacer (ITS) and the large subunit (LSU) (primer pairs ITS1/LR5, MW148514) of the rRNA genes (Aime 2006); phylogenetic analysis carried out in RAxMLv8.0.0 (Stamatakis 2014). Because of the inclination among Crataegus species to hybridize and the ornamental nature of the specimen, host identification was confirmed both morphologically and molecularly (ITS, primer pairs ITS1A/ITS4, MW148513, Lo et al. 2009) with 98 to 99% identity to C. marshallii sequences available in GenBank (MN215977, EF127037, EU683925), and it was placed within the other C. marshallii specimens in a broader phylogenetic estimate including sequence data from other available species of Crataegus (not shown). In agreement with the phylogenetic analysis, NCBI megaBLAST searches (Chen et al. 2015) of the resulting fungal sequences revealed 99% identity (ITS and LSU) to G. clavipes CUP-18207 (GenBank accession nos. MN605770, MN605692) and 99.65% identity (ITS and LSU, respectively; GenBank accession no. KT821552) against the strain of G. clavipes PUR N11552, first report of this rust occurring on another Rosaceae species, Pyrus calleryana Decaisne, in the United States (Creswell et al. 2016). Given the heteroecious and nonculturable nature of this pathogen, Koch’s postulates were not performed. This finding represents, to the best of our knowledge, the first record of G. clavipes in parsley hawthorn, and it adds to its broad range of known rosaceous hosts, having already been reported in 18 other species of Crataegus (Farr and Rossman 2020).

Association patterns of swollen‐thorn acacias with three ant species and other organisms in a dry forest of Panama

AbstractAnts in obligate defense mutualisms with plants protect them against potentially damaging organisms. In the swollen‐thorn acacias, organisms linked to the plant inform about the interaction between the tree and the resident ant colony. Some organisms coexist with the aggressive mutualistic ants: specialized herbivores and organisms using the enemy‐free space. Conversely, trees inhabited by non‐defending ants usually hold a greater load of generalist herbivores and are avoided by organisms looking for the ant protection. We aimed to elucidate the association type between swollen‐thorn acacias (Vachellia collinsii) and the almost unstudied Pseudomyrmex simulans ants from Panama. We compared the presence of non‐ant organisms on trees inhabited by P. simulans, a well‐known mutualist (P. spinicola) and a facultative parasite (non‐defending ants; Crematogaster crinosa). We recorded non‐ant organisms (e.g., stem galls, acacia true bugs, spiders) that nest, lay eggs, or live on the trees. Except for stem galls, all other non‐ant organisms were mostly or exclusively found on trees with the mutualists, which is also the most common resident ant. P. simulans is less able to deter galling midges (Cecidomyiidae) than C. crinosa and even less than P. spinicola, because trees with P. simulans were more likely to have galls and in greater densities than on C. crinosa‐trees, and even more than on P. spinicola‐inhabited trees. The mechanism by which the Cecidomyiids occur in greater proportion on trees with P. simulans and C. crinosa is still unknown, but the pattern indicates an herbivory specialization or a potentially obligate weaker defender of the swollen‐thorn acacias.Abstract in Spanish is available with online material

Economic Assessment of ICAR-NRCSS Coriander Variety (ACr-1) using Economic Surplus Model

Coriander, the major seed spice is grown in the Rajasthan, suffers from various fungal diseases, of which the stem gall being the most destructive and versatile disease causing up to 50 percent yield loss. ICAR-NRCSS Ajmer released a stem gall resistant variety named Ajmer Coriander-1 (ACr-1). Economic Surplus Model was used to examine the economic impact of ACr-1 in Rajasthan. The study found that the ACr-1 variety developed by the ICAR-NRCSS performed well as the net social benefit was `11105.83 million with 15 percent adoption of the variety during six years (2013-14 to 2018-19). The impact assessment study of the stem gall resistant variety (ACr-1) released by ICAR-NRCSS has earned positive social impact, and net returns to the coriander farmers can be further increased with wider adoption of this variety.

Evaluation of in vitro and in vivo management strategies against stem gall of coriander caused by Protomyces macrosporus (Unger.)

The present study was aimed to evaluate the effect of different biocontrol agents, botanicals and fungicides on crop yield and stem gall disease of coriander (Coriandrum sativum L.), caused by Protomyces macrosporus Unger. The effectiveness of plant leaf extracts, fungicides and bioagents were evaluated against the test fungus under in vitro conditions by using poisoned food technique and further evaluated under field conditions for disease management and crop yield improvement. Among the biocontrol agents and botanicals evaluated, Pseudomonas fluorescens and datura leaf extract were most effective in in inhibiting the pathogenic growth; whereas amongst fungicides, metalaxyl + mancozeb @ 0.2% and copper oxychloride @ 0.2% were significantly superior with 100% pathogenic growth inhibition under in vitro conditions. Under field conditions, seed treatment and foliar spray of metalaxyl + mancozeb and copper oxychloride @ 0.2% proved most effective in managing the disease as well as improved crop yield (1493.06 and 1284.72 kg ha-1, respectively) in comparison to the control (729.17 kg ha-1).

Characterization of Pterotylenchus cecidogenus in Desmodium ovalifolium cover crop from oil palm plantations in central Colombia.

Until recently, the stem gall nematode Pterotylenchus cecidogenus was only registered in eastern Colombia. However, the disease has recently been observed in central Colombian oil palm plantations that use Desmodium ovalifolium as a cover crop. Soil, root, stem, and leaf samples were collected from D. ovalifolium. Plants showed foliar yellowing, leaf drying, and galls within stem nodes. Nematodes were identified, and the distribution, population density, and relative importance of different genera were determined. We performed morphometric and molecular identification of nematodes associated with gall symptoms. The D2-D3 segment of the large subunit-28S of ribosomal ribonucleic acid (RNA) and internal transcribed spacer (ITS) was sequenced, and phylogenetic analysis was performed. P. cecidogenus mainly occurred in the galls and to a lesser extent in the roots and soil. Nematodes were not found in leaf or inflorescence tissue. Morphological and morphometric data confirm the presence of P. cecidogenus in the stems of D. ovalifolium with gall symptoms. This study is the first to report deoxyribonucleic acid (DNA) sequences of P. cecidogenus. Based on D2-D3 and ITS partial sequences, P. cecidogenus is a sister species of the leaf-galling nematode Ditylenchus phyllobius (Sinm. Orrina phyllobia).

Cyanogenesis prospection in galled and non-galled tissues of Microgramma squamulosa (Polypodiaceae)

Cyanogenic glycosides are defense substances that can produce hydrocyanic acid when they undergo hydrolysis as a result of herbivory, a process called cyanogenesis. Galls are neoformed structures of plant tissues induced by species-specific interactions between an inducer organism and a host plant. Earlier studies in Microgramma species have demonstrated that has a variation in cyanogenesis within and between populations, as well as in different plant organs. Microgramma squamulosa is an epiphytic fern that may contain stem galls induced by Tortrimosaica polypodivora (Lepidoptera: Tortricidae). Thus, the aim of the present study was to assess cyanogenesis seasonally and in different tissues (galled and non-galled) of M. squamulosa. The study was conducted in populations located in the Rio de Janeiro state, Brazil. Cyanogenesis was assessed using the Feigl-Anger paper test. A total of 260 galled and non-galled tissues were analyzed, 45 gall samples, 67 sterile leaves, 103 stems and 2 croziers. Cyanogenesis was detected in only three sterile leaf samples. In none of the samples were the stems or galls cyanogenic. The results corroborate the hypothesis that the stems of Microgramma squamulosa galled by Tortrimosaica polypodivora are not cyanogenic.

A New Species of Scrobipalpomima Povolný (Lepidoptera: Gelechiidae) Reared from Stem Galls of Adesmia spinosissima Meyen (Fabaceae) in the Andes of Northern Chile

The micromoth genus ScrobipalpomimaPovolný, 1985, mainly distributed in southern South America, is one of the more diverse Neotropical genera of Gonorimoschemini (Lepidoptera: Gelechiidae: Gelechiinae). The adult stage of Scrobipalpomima agustini sp. nov. is described and illustrated from the Andes of northern Chile. Larval feeding and pupation of S. agustini occur inside fusiform stem galls on the native spiny shrub Adesmia spinosissima Meyen (Fabaceae). The larva and pupa of S. agustini are illustrated and briefly described. This discovery expands the northern limit of Scrobipalpomima and represents the first record of immature stages and host plant for this genus of micromoths

Agrobacterium pusense, a new plant tumour‐inducing pathogen isolated from Lawson cypress

AbstractLawson cypress (Chamaecyparis lawsoniana), an important landscape tree, is widely planted in gardens and parks throughout Iran. Crown gall disease on Lawson cypress trees was observed in Sari and Juybar Counties, Mazandaran province, northern Iran, in 2017. Isolation from galls on potato dextrose agar (PDA) containing CaCO3 yielded bacterial colonies, the predominant types of which were purified and selected for characterization. The isolates were Gram‐negative, oxidase positive, able to grow in 2% NaCl and produced 3‐ketolactose. They hydrolysed esculin, casein and arbutin but not starch, gelatin or Tween 80. Two representative isolates were selected for PCR amplification and sequencing of DNA gyrase subunit B (gyrB) gene. In the phylogenetic tree based on the partial sequence of the gyrB gene, isolates KH1 and KH2 clustered with Agrobacterium pusense. The pathogenicity of all isolates was confirmed by inoculation on Jimsonweed (Datura stramonium) and carrot discs (Daucus carota). Confirmation of the presence of genes involved in pathogenicity was made by performing PCR with the virD2A/virD2C and VCF/VCR primer pairs which resulted in amplification of the expected 224 and 730 bp fragments in all studied isolates, respectively. A. pusense was therefore identified as the causal agent of crown and stem gall of Lawson cypress. This appears to be the first report on the natural occurrence of crown gall disease on Lawson cypress and the first record of a plant disease caused by A. pusense.

Agrobacterium tumefaciens causing crown and stem gall disease of citrus propagation nursery in Iran

Agrobacterium tumefaciens causing crown and stem gall disease of citrus propagation nursery in Iran

The effects of a stem gall fly and a leaf pathogen on the reproductive output of Crofton weed, Ageratina adenophora (Asteraceae), in greenhouse and field trials

Reducing the reproductive output of an invasive weed using biocontrol can result in a decrease in population density and help control the spread of the weed. Two biocontrol agents, a stem gall fly, Procecidochares utilis (Tephritidae), and a leaf-spot fungal pathogen, Passalora ageratinae (Mycosphaerellaceae), have been released against Crofton weed, Ageratina adenophora, in South Africa. In this study we investigated the impact of the agents, individually and together, on Crofton weed’s reproductive output, under both greenhouse and field conditions. Galling by P. utilis, with or without P. ageratinae, resulted in 32% fewer flowering structures per stem, compared to ungalled treatments in both the field and the greenhouse; however, without P. utilis, P. ageratinae did not reduce the number of flowering structures per stem. In the greenhouse, galled stems had 24% (single-galled)-55% (double-galled) fewer filled achenes than ungalled stems, while pathogen-infected stems had 27% fewer filled achenes per stem in comparison to uninfected stems. Although the biocontrol agents reduced the number of filled achenes, the percentage germination remained high and similar for all treatments (69.3–74.4%) in the field and the greenhouse. The combination of the two agents together did not provide more control of sexual reproduction than P. utilis alone. However, Crofton weed compensates for galling with increased sideshoot growth (vegetative reproduction), which in time also flower. But P. ageratinae inhibits growth of sideshoots. Therefore, the combination of the two agents best enhances the level of control rather than either agent in isolation.

In-vitro evaluation of six bio-product against coriander stem gall disease

Stem gall of coriander caused by Protomyces macrosporus Unger. is a highly devastating seed and soil borne pathogen in coriander and has emerged as one of the major disease causing substantial quantitative and qualitative losses. In the present studies, efficacy of six bio-products, namely, Neemazal, cow urine, butter milk, fresh milk, beejamrit and jeevamrit was screened against mycelial growth inhibition of P. macrosporus under in vitro conditions. Extracts of these bio-products were evaluated at three different concentrations (i.e 10, 20 and 30%) by poison food technique. Results revealed that that among the various bio-products evaluated against test pathogen, irrespective of concentration tested, all the bio-products resulted in significant inhibition in mycelial growth of test pathogen with neemazal giving the complete inhibition [100.00 % (90.00)] followed by fresh milk [30.66 % (28.44)] and butter milk [26.55 % (25.99)], though these treatments were statistically different from one another. Different concentrations (10 to 30 %) of bio-products, irrespective of the treatments showed that 30 per cent concentration of all bio-products was most efficacious in inhibiting the mycelial growth of the test pathogen giving 69.95 per cent (36.77) growth inhibition. This was followed 20 and 10 per cent concentration of bio-products resulting in 55.58 per cent (32.49) and 45.53 per cent (16.30) growth inhibition, respectively. The result regarding evaluation of bio-products under in vitro conditions against the P. macrosporus showed that Neemazal treatment was most effective at all concentrations and completely inhibited the test fungus followed by 30 per cent fresh milk resulting in the mycelial growth inhibition of 51.60 per cent.

Identification and preliminary characterization of chemosensory-related proteins in the gall fly, Procecidochares utilis by transcriptomic analysis

Chemoreception is critical for insect behaviors such as foraging, host searching and oviposition. The process of chemoreception is mediated by a series of proteins, including odorant-binding proteins (OBPs), gustatory receptors (GRs), odorant receptors (ORs), ionotropic receptors (IRs), chemosensory proteins (CSPs) and sensory neuron membrane proteins (SNMPs). The tephritid stem gall fly, Procecidochares utilis Stone, is a type of egg parasitic insect, which is an effective biological control agent for the invasive weed Ageratina adenophora in many countries. However, the study of molecular components related to the olfactory system of P. utilis has not been investigated. Here, we conducted the developmental transcriptome (egg, first-third instar larva, pupa, female and male adult) of P. utilis using next-generation sequencing technology and identified a total of 133 chemosensory genes, including 40 OBPs, 29 GRs, 24 ORs, 28 IRs, 6 CSPs, and 6 SNMPs. The sequences of these candidate chemosensory genes were confirmed by BLAST, and phylogenetic analysis was performed. Quantitative real-time PCR (qRT-PCR) confirmed that the expression levels of the candidate OBPs varied at the different developmental stages of P. utilis with most OBPs expressed mainly in the pupae, female and male adults but scarcely in eggs and larvae, which was consistent with the differentially expressed genes (DEGs) analysis using the fragments per kilobase per million fragments (FPKM) value. Our results provide a significant contribution towards the knowledge of the set of chemosensory proteins and help advance the use of P. utilis as biological control agents.

Identification and expression analysis of candidate genes associated with stem gall disease in Coriander (Coriandrum sativum L.) cultivars

Coriander (Coriandrum sativum L.) is a well-known spice and aromatic crop cultivated globally. Stem gall disease is one of the major constraints for its leaf and seed quality used for consumption and also affecting the yield. The identification of resistance genes and further characterization of such genes could help to understand the molecular basis of resistance and lay a solid ground for cloning of stem gall resistance genes in coriander. To evaluate the genetic expression of disease resistance-relevant genes in popularly grown coriander cultivars in India such as Pant Haritma, Hisar Sugandh, Hisar Surabhi, Hisar Anand, Rajendra Swathi, ACr-1, ACr-2, AgCr-1, CO-2 and CS-6 were used for LRR, GDSL, USP, ANK and PDR gene expression using Real Time PCR along with 18S housekeeping gene as internal control for the normalization. Result revealed the different expression pattern of genes among the cultivars tested. Highest expression was shown in cultivar AgCr-1 followed by Pant Haritma, Hisar Sugandh and ACr-1, and least expression in Hisar Anand, ACr-2, CO-2, Rajendra Swathi and CS-6. Domain analysis revealed the conserved domain relevance of the genes. This is the first report on stem gall resistance gene expression in coriander. The identified genes have a potential role in coriander and further utilize in crop improvement program. We hypothesize that contrasting cultivars can be a good source for candidate gene evaluation and further to use them as potential markers and used in hybridization program focus on incorporating and develop durable disease-resistance into the adapted cultivars of the region.