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Target-protein-based pesticide screening has attracted wide-ranging attention on pesticide science. Pedunsaponin A (PA) is a compound isolated from the root of Pueraria peduncularis, and it has a strong toxic effect on Pomacea canaliculata. Previous studies found that Advlin (PcAdv) and neural Wiskott-Aldrich syndrome isoform X1(PcnWAS) are target proteins of PA when interacted with P. canaliculata. In this study, we modeled the two target proteins through I-Tasser and identified the pharmacophore of PA binding to the two target proteins by molecular docking. Furthermore, through virtual screening, potassium alginate was found to strongly bind to the target proteins in theory. In vivo bioassay showed that, similar to PA treatment, potassium alginate was able to induce typical poisoning symptoms on P. canaliculata, which were characterized by abnormal increase of excreta, weakening of climbing capacity, loss of gill cilia and decrease in hemocyanin content, and even cause death of P. canaliculata with a 13.33% mortality rate under 100 mg L

Pseudomonas syringae pv. actinidiae (Psa) causes kiwifruit bacterial canker and poses a major threat to the kiwifruit industry. This study aimed to investigate the genetic characteristics of the Psa population from kiwifruit in Sichuan, China. Sixty-seven isolates obtained from diseased plants were characterized using morphological features, multiplex-PCR and multilocus sequence analysis (MLSA). The isolates exhibited the typical colony morphology of Psa. Multiplex PCR amplification identified every isolate as Psa biovar 3. MLSA analysis of the three housekeeping genes gapA, gyrB, and pfk, revealed that the reference strains of the five described biovars were clearly distinguished by a combined phylogenetic tree, and all the tested isolates clustered with the reference strains of Psa biovar 3. Through a phylogenetic tree constructed from a single gene, it was found that pkf gene alone could distinguish biovar 3 from the other biovars. Furthermore, all Psa isolates analyzed by BOX-A1R-based repetitive extragenic palindromic (BOX)-PCR and enterobacterial repetitive intergenic consensus (ERIC)-PCR clustered into four groups. The clustering results of BOX- and ERIC-PCR indicated that group III had the largest number of isolates, accounting for 56.72% and 61.19% of all sixty-seven isolates, respectively, and the two characterization methods were similar and complementary. The results of this study revealed that the genomes of Psa isolates from Sichuan had rich genetic diversity, but no obvious correlation was found between clustering and geographical region. This research provides novel methodologies for rapidly detecting kiwifruit bacterial canker pathogen and a molecular differentiation at genetic level of Psa biovars diversity in China.

Soybean (Glycine max L.) is one of the important oilseed and vegetable crop worldwide and provides the main source of vegetable oil and proteins for human and livestock (Hartman et al. 2011). In October 2021, approximately 35% of soybean pods suffered from anthracnose in the farmer’s field in Chongzhou, Sichuan Province, China (103°40'12"E, 30°37'48"N), and the occurrence area accounted for about 3.3 hm2. Symptoms of soybean were characterized by yellow spots at the initial stage, gradually expanded into dark brown spots, and eventually amounts of small black particles were densely arranged in the wheel shape on dead spots. Diseased spots of soybean pods were cut into pieces and sequentially sterilized in 75% alcohol for 30 s, 4% sodium hypochlorite for 30 s, sterile water for 3 times. After that, these pieces were placed on potato dextrose agar (PDA), and incubated at 25±2°C in the dark for 5-7 days. Single spore was separately picked and transferred to a fresh PDA plate to obtain pure culture isolates. Total six pure isolates were collected, and among them the hyphae of representative isolate 8-B were initially white, turned grey gradually on PDA medium, and the colonial reverse were radiating, whorled or a mixture of both. Conidia of 8-B were septate, hyaline, unicellular, cylindrical, obtusely rounded at both ends with 1 or 2 oil balls inside, and 10.5-17.6 µm in length and 7.0 µm-3.6 µm in width (n=100). The conidial appressoria were brown subspherical, 6.9 µm-13.3 µm in length and 5.6 µm-10.1 µm (n=50) in width. Based on morphological and cultural characteristics, the isolate 8-B was tentatively identified as Colletotrichum gloeosporioides species complex（Weir et al. 2012). To test pathogenicity, the mycelial plugs were inoculated on 20 detached soybean pods at full seed (R6) stage, and three areas of each pod were lightly scratched using a needle prior to inoculation. As controls, the PDA plugs were attached to the pinned-treated pods. Three independent replicates were conducted for control and inoculated pods, respectively. All pods were incubated in a greenhouse at 25 ± 2°C with a relative humidity of approximately 90%. After 4-5 days post-inoculation, typical anthracnose lesions were observed on the inoculated pods while the control pods remained healthy only with small wound spots. The pathogen re-isolated from all the inoculated pods were morphologically identical to the inoculation isolate (8-B). For further molecular verification, the six gene fragments including the internal transcribed spacer (ITS), glyceraldehyde-3-phosphate dehydrogenase (GAPDH), chitin synthase 1 (CHS-1), actin (ACT), β-tubulin 2 (TUB2) and calmodulin (CAL) were amplified and sequenced (Weir et al. 2012, Damm et al. 2012), and the obtained sequences were deposited in GenBank (Accession numbers ON960278, ON685214, ON964475, ON974476, ON685215 and ON964477, respectively). All six gene sequences of 8-B had a high identity to C. fructicola (the stand isolate ICMP 18581) with the accession numbers ON960278 (100%), ON974476 (96%), ON685214 (99%), ON964475 (99%), ON685215 (100%), and ON964477 100%), respectively. Anthracnose disease caused by C. fructicola has previously been reported to affect a range of plant hosts worldwide (Guarnaccia et al. 2017). However, it is still unknown on C. fructicola causing anthracnose in soybean in China. This study firstly reports C. fructicola as the causal agent of anthracnose on soybean in the country, and provides a theoretical basis for the diagnosis and control of this disease.

Five compounds were identified from Tripterygium wilfordii, including two novel compounds and three previously known compounds. Two newly discovered compounds are celangulin CY (1α,2α,3β,4β,6β,8α,13-hepacetoxy-9β-benzoyloxy-β-dihydroagarofuran) and celangulin CQ (1α-nicotinoyloxy-2α,3β,6β-triacetoxy-9β-furancarbonyloxy-13-isobutanoyloxy-4β-hydroxy-β-dihydroagarofuran). Their structures were determined using nuclear magnetic resonance (NMR), mass spectrometry (MS), and high-pressure liquid chromatography (HPLC). The isolated compounds were tested for insecticidal activity against the third instar larvae of Spodoptera frugiperda. Both celangulin CY and celangulin CQ exhibited significantly higher oral toxicity in the larvae than that exhibited by the three known compounds.

The umpolung Michael addition of isatin N,N′-cyclic azomethine imine 1,3-dipoles with chalcones is reported. The reaction could be finished within a very short time (0.3–2 min), with 3,3-disubstituted oxindole derivatives obtained in moderate to excellent yields with promising dr values. Unusual Michael adducts were obtained in moderate to high yields (26–98%) with low to high diastereoselectivities (0.8 : 1 to 8.5 : 1 dr). All the synthesized compounds (3, 3′, 4, 5, 5′, 7, 7′, 9 and 9′) were well characterized by FTIR, NMR, and mass spectral analyses and further confirmed by the single-crystal X-ray diffraction analysis of compounds 3aa and 4n.

Previous studies have found that temperature influences molluscicidal the activity of pedunsaponin A (PA), which may be related to the expression of Hsp70, a cold-tolerance gene in Pomacea canaliculata. We determined the temperature effect of PA and the relationship between Hsp70 and temperature sensitivity of P. canaliculata poisoned by PA. Toxicity tests resulted in LC

BackgroundThe dynamic of soil-borne disease is closely related to the rhizosphere microbial communities. Maize-soybean intercropping can suppress soybean root rot as compared to monoculture. However, it is still unknown whether rhizosphere microbial community participates in the regulation of intercropped soybean root rot.MethodsIn this study, the difference of rhizosphere Fusarium and Trichoderma community was compared between healthy or root-rotted soybean rhizosphere soil from soybean monoculture and maize-soybean intercropping, and the inhibitory effect of potential biocontrol Trichoderma against pathogenic Fusarium were examined.ResultsThe abundance of rhizosphere Fusarium was remarkably different between intercropping and monoculture, while Trichoderma was largely accumulated in healthy rhizosphere soil of intercropping rather than monoculture. Four rhizosphere Fusarium species identified were all pathogenic to soybean but displayed distinct composition and isolation proportion in the corresponding soil types. As the dominant and most aggressive species, F. oxysporum was more frequently isolated in diseased soil of monoculture. Furthermore, of three Trichoderma species identified, T. harzianum dramatically increased in the rhizosphere of intercropping rather than monoculture as compared to T. virens and T. afroharzianum. For in-vitro antagonism test, Trichoderma strains had antagonistic effects on F. oxysporum with the percentage of mycelial inhibition ranging of 50.59%-92.94%, and they displayed good mycoparasitic abilities against F. oxysporum through coiling around and entering into the hyphae, expanding along cell-cell lumen and even dissolving cell walls of target fungus.Conclusion These results indicate maize-soybean intercropping significantly increase the density and composition proportion of beneficial Trichoderma to antagonist the pathogenic Fusarium species, thus contributing to the suppression of soybean root rot under intercropping.

BACKGROUND Based on previous research indicating that pedunsaponin A (PA) can destroy the gills of Pomacea canaliculata, we chose the gill as the main research object, and identified the target protein of PA in the gills of P. canaliculata through proteomics and RNA interference (RNAi). RESULTS Proteomics showed that 180 proteins were downregulated after PA treatment in P. canaliculata. Among them, we chose advillin (PcAdv), receptor type tyrosine protein phosphatase (PcRT) and unconventional myosin heavy chain 6 (PcUM) as candidate target proteins through bioinformatics analysis. The small interfering RNA (siRNA) with the best interference effect was identified through further screening. Gene interference rates were 97%, 98% and 82% for PcAdv, PcRT and PcUM, respectively. The results showed that after RNAi treatment, the mortality of P. canaliculata treated with PcAdv (60.0%) was significantly lower than that for the control (93.3%); histological analysis showed that the structure of the gill was intact, cilia shedding was reduced, and the survival rate of hemocytes had increased. CONCLUSION These findings indicate that, when the protein was absent or suppressed, the channel for entry of PA into the hemocytes of P. canaliculata was blocked, which reduced PA binding to hemocytes, and that there is a close relationship between shedding of gill cilia and PA entry into hemocytes. PcAdv is thus the key protein in PA destruction of gill cilia. Locating the proteins in gills that interact with drugs and investigating their mode of action is of great importance in the development of new molluscicides to control P. canaliculata populations.

The rapid synthesis of novel dicyclic spiropyrrolidine was reported, using [3+2]-cycloaddition of isatin N,N′-cyclic azomethine imine 1,3-dipoles, generated from the condensation of substituted isatins and pyrazolidones, with chalcones in 2–5 min. The dicyclic spiropyrrolidine oxoindole was smoothly acquired in moderate to excellent yields (35–95%) with high diastereoselectivities (>20 : 1 dr).

To develop long-afterglow luminescent materials for white LEDs application, a series of Sr1·97MgSi2O7-1.5xNx:0.01Eu2+,0.02Dy3+ (0 ≤ x ≤ 0.49) phosphors were designed. The single-phase samples were confirmed and the introduction of N was verified by the XRD patterns and energy-dispersive X-ray spectrum. The average particle size of the phosphors was determined to be about 4.9 μm. When the N is doped, it has been found the Eu2+ emission intensity decreases gradually, which could be owing to the increasing crystal defects by the nonequivalent substitution between N and O. The excitation spectra reveal that the broad and strong excitation bands from 240 to 450 nm can well match the LED chip. It is interesting that the incorporation of N can improve the afterglow time, which has been interpreted by the thermoluminescence curves. The investigation of the temperature-dependent luminescence indicates a beneficial effect on the thermal stability by doping N in the phosphors.

Glabridin is a natural plant-derived compound that has been widely used in medicine and cosmetic applications. However, the fungicidal mechanism of glabridin against phytopathogens remains unclear. In this study, we determined the biological activity and physiological effects of glabridin against F. graminearum. Then the differentially expressed proteins of F. graminearum were screened. The EC50 values of glabridin in inhibiting the mycelial growth and conidial germination of F. graminearum were 110.70 mg/L and 40.47 mg/L respectively. Glabridin-induced cell membrane damage was indicated by morphological observations, DiBAC4(3) and PI staining, and measurements of relative conductivity, ergosterol content and respiratory rates. These assays revealed that the integrity of the membrane was destroyed, the content of ergosterol decreased, and the respiratory rate was inhibited. A proteomics analysis showed that 186 proteins were up-regulated and 195 proteins were down-regulated. Mechanically sensitive ion channel proteins related to transmembrane transport and ergosterol biosynthesis ERG4/ERG24, related to ergosterol synthesis were blocked. It is speculated that glabridin acts on ergosterol synthesis-related proteins to destroy the integrity of the cell membrane, resulting in abnormal transmembrane transport and an increased membrane potential. Finally, the morphology of mycelia was seriously deformed, growth and development were inhibited. As a result death was even induced.

Previous study found that pedunsaponin A (PA) influenced the cytoskeleton of Pomacea canaliculata hemocytes, leading to depolarization and haemocyte destruction and eventually to snail death. In this study, we analysed the changes in protein expression by iTRAQ-mediated proteomics and identified 51 downregulated proteins. Among these, we focused on proteins related to cytoskeletal function and identified neural Wiskott-Aldrich syndrome isoform X1 (PcnWAS). The full-length PcnWAS gene contains 9791 bp and includes an open reading frame of 1401 bp that encodes 735 amino acids with a predicted molecular mass of 49.83 kD. PcnWAS exhibited a relatively distant genetic relationship with known species; the closest homologue is Biomphalaria glabrata (57%). RNA interference (RNAi) was adopted to verify the function of PcnWAS after screening the siRNA sequence with an efficiency of 97%. Interference with the gene expression of PcnWAS did not lead to snail death, but the depolarization level increased, which demonstrated that PcnWAS is an important depolarization-related protein. The results of PA treatment of snails subjected to RNAi proved that interfering with PcnWAS gene expression decreased the molluscicidal activity of PA toward P. canaliculata; snail mortality after RNAi was significantly lower (40%) than that in PA-treated snails without RNAi (54%), while the survival rate and depolarization level in haemocytes were not significant, indicating that PcnWAS is only one of the important target proteins of PA in P. canaliculata. This study lays the foundation for further exploration of the molecular mechanism by which PA kills this harmful snail.

A series of Yb3+-Er3+, Yb3+-Ho3+, and Yb3+-Tm3+ doped Ca2Gd8(SiO4)6O2 (CGS) phosphors were synthesized by solid-state reaction method, and their upconversion (UC) luminescence properties for temperature sensing were studied. Upon 980 nm excitation, the green and red emissions of Er3+ were observed, and the optimal Er3+ concentration was determined to be 3 mol%. For the CGS:10%Yb3+,yHo3+ phosphors, three emission peaks in the green, red and near-infrared region appear. It was found that the relative intensities of Ho3+ different emissions change with Ho3+ concentration, which has been explained by the cross-relaxation process. The strongest Tm3+ emission appeared at 790 nm, attributed to the 3H4-3H6 transition. The optimal Tm3+ concentration was determined to be 0.5 mol%. The temperature sensing behavior was evaluated by employing the thermally-coupled or non-thermally coupled levels of Er3+, Ho3+ and Tm3+. The maximum sensitivities obtained are 3.71 × 10 − 3 and 1.12 K-1 for CGS:10%Yb3+,3%Er3+, 0.111 K-1 for CGS:10%Yb3+,3%Ho3+ and 3.3 × 10 − 4 K−1 for CGS:10%Yb3+,0.5%Tm3+, respectively. The high sensitivities indicate the present phosphors could have potential application in temperature sensing.

Many species of the genus Bipolaris are important plant pathogens and often cause leaf spot, root rot, and seedling blight in an extremely wide range of hosts around the world. In recent years, maize leaf spot caused by Bipolaris species has frequently occurred with complex symptoms and is becoming increasingly serious in Sichuan Province of China. To investigate the population diversity of Bipolaris spp. and their corresponding symptoms in maize, 747 samples of maize leaf spot were collected from 132 sampling sites in 19 administrative districts of Sichuan Province from 2011 to 2018. Based on morphological characteristics, pathogenicity testing, and phylogenetic analysis of the rDNA internal transcribed spacer (ITS) and glyceraldehyde-3-phosphate dehydrogenase (GAPDH) genes, a total of 1186 Bipolaris isolates were identified as B. maydis, B. zeicola, B. cynodontis, B. oryzae, B. setariae, and B. saccharicola, among which B. maydis and B. zeicola were the dominant pathogenic species, accounting for 57.34% and 42.07% of the isolates, respectively. We found that B. zeicola isolates were mainly distributed in high altitude and cool mountainous areas, while B. maydis was more widely distributed in Sichuan Province. The typical symptoms caused by the Bipolaris species were clearly distinct in maize. The typical symptoms caused by B. maydis were elongated strip lesions, or fusiform, elliptical lesions, and those caused by B. zeicola were narrow linear lesions. Herein, B. saccharicola was first reported on maize and caused subrotund lesions. This study provides useful information for disease diagnosis and management for Bipolaris leaf spot in maize.

Two oleanane-type triterpenoid saponins named pedunsaponin D (1) and pedunsaponin E (2) were isolated from the roots of Pueraria peduncularis. The structures of the new compounds were elucidated based on chemical and physicochemical evidence as follows: pedunsaponin D, 3-O-β-glucopyranosyl-(1-3)-β-glucuronopyranosyl-3β,15α,23α-trihydroxy-11,13(18)-oleanadien-16-one (1); pedunsaponin E, 3-O-β-glucopyranosyl-(1-2)-β-glucopy ranosyl(1-2)[β-glucopyranosyl(1-3)-β-glucuronopyranosyl]-3β-hydroxy-16-oxoolean-12-en-30-oic acid (2). The two compounds showed moderate molluscicidal activity.[Formula: see text].

The synthesis of novel spiropyrrolidine oxindole derivatives was reported, using Ag-catalyzed [3+2] cycloaddition of azomethine ylides generated in situ from the condensation of substituted isatins and primary α-amino acid esters with chalcones. Products bearing four consecutive stereocenters, including spiroquaternary stereocenters fused in one ring structure, were smoothly acquired in moderate to high yields (50–95%) with good to excellent diastereoselectivities (11 : 1 → 20 : 1 dr). Furthermore, product 4a underwent reduction, oxidation, hydrolysis and amidization to give the corresponding alcohol, dihydropyrrole, pyrrole, acid and amide, respectively, in good yields. The synthesized compounds (>100 examples) were well characterized through different spectroscopic techniques, such as single crystal XRD, FTIR, NMR, and mass spectral analysis.

Pomacea canaliculata is an invasive snail that can adversely affect biodiversity, agricultural crop yields and human health. Schima superba, which belongs to the Theaceae family, exhibits insecticidal and antibacterial activity, but few studies have focused on its potential molluscicidal activity. In this study, we systematically evaluated the molluscicidal activity of S. superba extract against P. canaliculata in a variety of conditions, including multiple exposure intervals (24, 48 and 72 h), temperatures (15, 20 and 25 °C) and shell diameters (1.5 ± 0.2, 2.5 ± 0.2 and 3.5 ± 0.2 cm). The molluscicidal activities of a 10% microemulsion of S. superba extract were tested on rice in plastic pots filled with mud at different exposure intervals (1, 3, 5 and 7 days). In addition, we isolated and purified the active components from S. superba extract and described them. S. superba was highly toxic to P. canaliculata; the LC50 values for the crude extract at 72 h were 12.25 mg L−1 (15 °C), 11.31 mg L−1 (20 °C), 8.33 mg L−1 (25 °C) with 2.5 ± 0.2 cm shell diameter and 9.43 mg L−1 (1.5 ± 0.2 cm shell diameter), 9.48 mg L−1 (2.5 ± 0.2 cm shell diameter), 10.06 mg L−1 (3.5 ± 0.2 cm shell diameter) at 25 °C. There was a positive correlation between the molluscicidal activity of the extract and treatment temperature after 24 h of treatment, but there was no clear correlation beyond 24 h. In addition, there was no statistically significant correlation between the molluscicidal activity of the extract and shell diameters. Pot trials showed that the crude extract effectively controlled P. canaliculata at 8 and 10 mg L−1. We isolated and characterized two pentacyclic triterpenoid saponins from S. superba, maetenoside B and sasanquasaponin III, which had high molluscicidal activity. This study provides an important foundation for future research on the potential value of S. superba as a molluscicide.

A new synthetic method for 2-arylindoles has been developed, the process through Suzuki coupling reaction of 3-bromoindoles with hindered boronic acid catalyzed by Pd(OAc)2/PCy3, and a series of 2-arylindoles have been synthesized in moderate to high yields.

Transcriptomes, genomes, and proteomes have played important roles in the search for drug targets. To determine the molluscicidal mechanism of pedunsaponin A against Pomacea canaliculata, RNA-seq technology was adopted to analyze the differentially expressed genes (DEGs) in the P. canaliculata transcriptome after treatment with pedunsaponin A. As a result, 533 DEGs were identified, among which 255 genes were significantly upregulated and 278 genes were significantly downregulated. According to the analysis of Gene Ontology (GO) functions, we found that the DEGs were significantly enriched in the viral life cycle, UDP-glucose 4-epimerase activity, guanylate cyclase activity, the cyclic guanosine monophosphate (cGMP) biosynthetic process, and the cGMP metabolic process. The Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway results showed that the DEGs were mainly involved in the hedgehog signaling pathway, phagosome, cytosolic DNA-sensing pathway, retinoic acid-inducible gene I like (RIG-I-like) receptor signaling pathway, bacterial secretion system, and nuclear factor-kappa B (NF-kappa B) signaling pathway. The above results indicated that pedunsaponin A causes a metabolic disorder, anomalous opening of membrane ion channels, and an imbalance in osmotic pressure between the interior and exterior of cells, eventually resulting in the death of cells involved in immune defense and influencing the immune response of P. canaliculata.

Pomacea canaliculata hemocytes are the main functional cells in the immune defense system, and hemocyte destruction disrupts the immune response mechanism of P. canaliculata, resulting in abnormal growth, development, reproduction, and even death. Our previous study found that Pedunsaponin A significantly affects P. canaliculata hemocyte structure. This study further investigated the damaging effects of Pedunsaponin A on P. canaliculata hemocytes. The cell mortality rate results showed that the hemocyte mortality was significantly increased after treatment with Pedunsaponin A, and the mortality rate exhibited a significant positive correlation with treatment time and dose. The membrane potential results showed that the cell membranes of P. canaliculata hemocytes exhibited time-dependent membrane depolarization after 40 mg/L Pedunsaponin A treatment. At 36 h, the cell depolarization rate in the Pedunsaponin A treatment group was 41.43%, which was significantly greater than the control group (6.24%). The cytoskeleton results showed that Pedunsaponin A led to disordered and dispersed arrangement of microfilaments and changes in the cytoskeletal structure. The apoptosis and cell cycle results showed that Pedunsaponin A induced apoptosis and influenced the cell cycle to some extent. These results showed that the cell membrane and cytoskeleton of P. canaliculata hemocytes were damaged after treatment with Pedunsaponin A, which led to an increase in cell mortality, dysfunction, cell cycle abnormalities and apoptosis. This study provides a foundation for further identification of the site of Pedunsaponin A activity on hemocytes.

Wheat powdery mildew, caused by the fungal pathogen Blumeria graminis f. sp. tritici, is one of the most destructive wheat diseases in China, especially in Sichuan Province. Successfully oversummered B. graminis f. sp. tritici can become a primary infection source for wheat seedlings in the fall. Determining the latent infection level of B. graminis f. sp. tritici in volunteer wheat and the oversummering areas of B. graminis f. sp. tritici is important for estimating potential B. graminis f. sp. tritici epidemics. In this study, we clarified the critical role of volunteer wheat in the B. graminis f. sp. tritici oversummering cycle and determined whether latent B. graminis f. sp. tritici infection was present in volunteer wheat by using real-time polymerase chain reaction (real-time PCR). The results indicated that volunteer wheat was mostly found in the northeast and middle regions of Sichuan, where lower temperatures and higher precipitation are common. A total of 13.2% of samples showed symptoms of B. graminis f. sp. tritici (spores) in the field, and 36.8% of samples were found to carry the B. graminis f. sp. tritici pathogen, even though no symptoms were observed. Volunteer wheat with B. graminis f. sp. tritici infection symptoms was found at an altitude of 536 m but volunteer wheat latently infected by B. graminis f. sp. tritici was identified at the lowest altitude of 323 m. Crop shade (e.g., corn and lima bean) provided suitable conditions for the survival of volunteer wheat in the summer. In addition, volunteer wheat played a key role in the B. graminis f. sp. tritici oversummering cycle. Moreover, B. graminis f. sp. tritici could oversummer by infecting generations of volunteer wheat in the summer, thereby becoming the primary infection source for autumn-sown wheat. The results showed that the latent infection of wheat diseases could be rapidly quantified by real-time PCR. Here, the primary disease center of autumn-sown wheat in Ya’an and Wenjiang were detected accurately based on this method. This study provides solid evidence for identifying the disease center, which offers guidance for wheat disease control and management.

BACKGROUND Pueraria peduncularis (Grah. ex Benth.) Benth., which belongs to the Leguminosae family, exhibits resistance to many crop pests in agricultural production. Pomacea canaliculata is an important invasive snail in rice fields and causes severe yield losses. To evaluate the toxicity of P. peduncularis to P. canaliculata, in this study the molluscicidal activity of root extracts of P. peduncularis was tested against P. canaliculata; the active compounds were isolated, and the structures of these compounds were analysed using nuclear magnetic resonance (NMR) analysis and mass spectral analysis. RESULTS Our results showed that the molluscicidal activity of the root crude extract differed between P. canaliculata with different shell diameters after treatment for 72 h. The median lethal concentration (LC50) was 5.511 mg L−1 against snails of 1.5 ± 0.2 cm diameter and 12.383 mg L−1 against snails of 2.5 ± 0.2 cm diameter. Furthermore, two active ingredients isolated from root methanol extracts were identified as pedunsaponin A and pedunsaponin C. Both pedunsaponin A and pedunsaponin C showed strong molluscicidal activities, with LC50 values of 3.893 and 4.252 mg L−1, respectively, against snails with shell diameters of 1.5 ± 0.2 cm after treatment for 72 h. CONCLUSION Pueraria peduncularis extracts exhibit high molluscicidal activity and have great potential value for exploring a molluscicide to control Pomacea canaliculata. © 2016 Society of Chemical Industry