Characterization of the complete mitochondrial genome of the maize weevil, Sitophilus zeamais (Insecta: Coleoptera: Curculionidae) from Guizhou province.
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ABSTRACT:
SUBMITTER: Zhou X
PROVIDER: S-EPMC7510821 | biostudies-literature |
REPOSITORIES: biostudies-literature
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Project description:The complete mitochondrial genome (mitogenome) of Sitophilus zeamais was determined by an Illumina platform. This mitogenome was 18,531 bp in length, containing 13 protein coding genes, 2 rRNA genes, 22 tRNA genes that is typical among curculionoidea. Stop codon was incomplete for ND4 gene and ND5. The non-coding intergenic regions have increased in size to 1033 bp due to expansion of tandem repeat arrays. Phylogenetic analysis on mitogenome of S. zeamais would further contribute to resolve phylogenetic position and interrelationships of Sitophilus.
| S-EPMC7850447 | biostudies-literature
Project description:Toxicities of leaf powders and extracts of Acanthus montanus, Acanthospermum hispidum, Alchornea laxiflora and Argyreia nervosa against maize weevil (Sitophilus zeamais) were evaluated. Powders were tested at dose 3.0g/20g while extracts were tested at concentration 3%/20g of maize grains. Mortality, oviposition, and adult emergence rates as well as weight loss, seeds damage and weevil perforation index (WPI) were evaluated. Phytochemical constituents of the experimental plants were also carried out. The results showed that Acanthus montanus powder was the most potent with 65% adult mortality after 24 h of treatment. This is followed by Argyreia nervosa powder that evoked 52.5% weevil mortality. The least toxic to S. zeamais was Acanthospermum hispidum powder with 32.5% adult mortality. Extracts were more toxic than the powders of the tested plants. Acanthus montanus extract was the most toxic since it promoted 80% adult mortality after 24 h of treatment. Acanthus montanus, Alchornea laxiflora and Argyreia nervosa leaf powders and extracts completely prevented oviposition by adult insect, adult emergence, weight loss and seeds damaged. The phytochemicals present in Acanthus montanus were alkaloids (3.67 mg/g), saponin (3.33 mg/g), tannin (3.00 mg/g) and flavonoid (2.67 mg/g) contents. Acanthospermum hispidum had the least alkaloid (2.67 mg/g), saponin (1.67 mg/g), tannin (1.33 mg/g) and flavonoid (1.00 mg/g) contents. Acanthus montanus, Argyreia nervosa, Alchornea laxiflora and Acanthospermum hispidum were efficacious against S. zeamais instead of synthetic chemical insecticides that have environmental health hazards and they can be used in integrated pest management by farmers and foods merchants.
| S-EPMC7343657 | biostudies-literature
Project description:Sitophilus zeamais Motschulsky is the most important insect pest of stored maize in tropical regions. The objective of this study was to determine the practicality of periodic physical disturbance on S. zeamais mortality and its adoption by smallholder farmers in developing countries. In this experiment, treatments and control were arranged in a randomized block design with three replications and three storage times in three regions of Tanzania. Region was used as the blocking variable. A total of 108 clean 20-L plastic containers were each loaded with 10 kg of fresh white dent corn and 0.50 kg of maize infested with S. zeamais. For the treatment, containers were disturbed twice a day, whereas for the controls the containers were not disturbed until the end of storage. The overall mortality rate (%) after 30, 60, and 90 days of storage were 88%, 96%, and 98%, respectively. A statistically significant difference (p < 0.05) was observed for the number of live S. zeamais between the control and experimental treatments. Additionally, the number of live S. zeamais in the treatment significantly decreased as storage time increased. This study shows the potential of a feasible, simple, affordable, and effective method of protecting maize grain for small-holder farmers in developing countries without using chemicals.
| S-EPMC5198199 | biostudies-literature
Project description:Chemical control of the maize weevil (Sitophilus zeamais) has been ineffective and presents serious collateral damage. Among plant-derived insecticides, essential oils (EOs) are suitable candidates to control this stored products pest. In this work, the insecticidal activities of 45 natural EOs against S. zeamais adults were screened, and the most promising ones (24 EOs) were characterized by GC-MS. The repellent and toxic effects (contact and fumigant) of these 24 EOs were determined, and by a cluster analysis they were classified into two groups considering its fumigant activity and contact toxicity. For the EOs with the highest fumigant potential (14 oils) and their main active constituents (17 compounds), lethal concentrations were determined. The most active EOs were those obtained from L. stoechas and L. alba, with LC50 values of 303.4 and 254.1 µL/L air and characterized by a high content of monoterpenes. Regarding the major compounds, the oxygenated monoterpenes R-(+)-pulegone (LC50 = 0.580 mg/L air), S-(-)-pulegone (LC50 = 0.971 mg/L air) and R-(-)-carvone (LC50 = 1.423 mg/L air) were the most active, as few variations in their concentrations significantly increased insect mortality.
| S-EPMC8230103 | biostudies-literature
Project description:Individual traits vary among and within populations, and the co-occurrence of different endosymbiont species within a host may take place under varying endosymbiont loads in each individual host. This makes the recognition of the potential impact of such endosymbiont associations in insect species difficult, particularly in insect pest species. The maize weevil, Sitophilus zeamais Motsch. (Coleoptera: Curculionidae), a key pest species of stored cereal grains, exhibits associations with two endosymbiotic bacteria: the obligatory endosymbiont SZPE ("Sitophilus zeamais Primary Endosymbiont") and the facultative endosymbiont Wolbachia. The impact of the lack of SZPE in maize weevil physiology is the impairment of nutrient acquisition and energy metabolism, while Wolbachia is an important factor in reproductive incompatibility. However, the role of endosymbiont load and co-occurrence in insect behavior, grain consumption, body mass and subsequent reproductive factors has not yet been explored. Here we report on the impacts of co-occurrence and varying endosymbiont loads achieved via thermal treatment and antibiotic provision via ingested water in the maize weevil. SZPE exhibited strong effects on respiration rate, grain consumption and weevil body mass, with observed effects on weevil behavior, particularly flight activity, and potential consequences for the management of this pest species. Wolbachia directly favored weevil fertility and exhibited only mild indirect effects, usually enhancing the SZPE effect. SZPE suppression delayed weevil emergence, which reduced the insect population growth rate, and the thermal inactivation of both symbionts prevented insect reproduction. Such findings are likely important for strain divergences reported in the maize weevil and their control, aspects still deserving future attention.
| S-EPMC4210188 | biostudies-literature
Project description:The maize weevil, Sitophilus zeamais, is a worldwide pest that disproportionately affects subsistence farmers in developing countries. Damage from this pest threatens food security in these communities as widely available and effective control methods are lacking. With advances over the last decade in the development of genetic pest management techniques, addressing pest issues at the ecosystem level as opposed to the farm level may be a possibility. However, pest species selected for genetic management techniques require a well-characterized genome and few genomic tools have been developed for S. zeamais. Here, we have measured the genome size and developed the first genetic linkage map for this species. The genome size was determined using flow cytometry as 682 Mb and 674 Mb for females and males, respectively. The linkage map contains 11 linkage groups, which correspond to the 10 autosomes and 1 X-chromosome found in the species and it contains 1,121 SNPs. This linkage map will be useful for assembling a complete genome for S. zeamais.
| S-EPMC10276983 | biostudies-literature
Project description:The rice weevil, Sitophilus oryzae (Linnaeus, Coleoptera: Curculionidae), is a serious cosmopolitan pest that affects grain in storage and has developed high levels of resistance toward phosphine. In this study, RNA-seq data was used to study the phosphine resistance mechanisms in S. oryzae. Resistant and susceptible populations of S. oryzae were identified based on phosphine bioassays conducted in 32 populations collected across Tamil Nadu, India. Differential expression of mitochondrial (COX1, COX2, COX3, ND2, ND3, ATP6, and ATP8) and detoxification genes (Cyps, Gsts, and Cbe) were observed in the resistant and susceptible populations of S. oryzae. The previously characterized phosphine resistant gene, dld (dihydrolipoamide dehydrogenase) linked to the rph2 locus, was found to be up-regulated in resistant S. oryzae population (ISO-TNAU-RT) treated with phosphine. Also, the genes involved in Tricarboxylic acid (TCA) cycle were significantly down-regulated. In addition, a significant up-regulation in the expression of the antioxidant enzymes superoxide dismutase (2.5×) and catalase (2.1×) in ISO-TNAU-RT populations was recorded. Furthermore, a distinct amino acid substitution, Lysine > Glutamic acid (K141E) was identified in resistant phenotypes. In silico docking studies of both resistant and susceptible DLD protein with phosphine molecule revealed that the amino acid residues involved in the interaction were different. This suggested that the amino acid substitution might lead to structural modifications which reduces the affinity of the target (phosphine). This study provides insight on the various genes, pathways, and functional mechanisms having a significant role in phosphine resistance in S. oryzae.
| S-EPMC10757423 | biostudies-literature
Project description:Smallholder maize farmers in Africa experience pre- and post-harvest production stresses either individually or in combination at different stages of the crop cycle. The maize weevil is among the major post-harvest storage pests. A strategy to address this problem is to develop and promote high yielding maize germplasm with resistance to multiple stresses. A study was conducted to: 1) assess yield and agronomic performance of testcross hybrids developed from early generation lines; and 2) assess the response of the testcross hybrids to infestation with Sitophilus zeamais. Fifty-eight drought-tolerant testcross hybrids were evaluated for agronomic performance and weevil resistance at four environments in Uganda in 2016. Hybrid G39 (L2/T2) had the best grain yield performance; it significantly out-performed the best check by 11.4% in all environments. Hybrid grain from field trials was subjected to Sitophilus zeamais infestation in a choice and no choice test under laboratory conditions. Hybrids G56 (L49/T2) and G58 (L51/T2) had the least weevil damage and were rated as resistant to Sitophilus zeamais. The numbers of damaged kernels, number of exit holes and ear aspect were positively correlated with the grain weight loss. The results suggest possibilities for simultaneous selection for high grain yield and storage insect pest resistance among drought-tolerant genotypes. Use of high-yielding and resistant maize hybrids to storage insect pest should be promoted for increased maize production and managing post-harvest losses due to the maize weevil in smallholder farming communities in Africa.
| S-EPMC7649906 | biostudies-literature
Project description:The rice weevil, Sitophilus oryzae (L.) (Coleoptera: Curculionidae) could cause significant grain loss by feeding internally on seeds. In this study, we tried to analyze the volatile compounds in non-infested and S. oryzae-infested brown rice during different storage periods to identify potential markers in S. oryzae-infested brown rice and facilitate pest monitoring during brown rice storage. Headspace solid-phase microextraction gas chromatography-mass spectrometry (HS-SPME-GC-MS) and headspace-gas chromatography-ion mobility spectrometry (HS-GC-IMS) were used to identify the volatile compounds. On the basis of GC-MS and GC-IMS data, a reliable method to distinguish between non-infested and S. oryzae-infested brown rice was discovered using partial least squares-discriminant analysis (PLS-DA). 1-Octen-3-ol, 1-hexanol and 3-octanone were co-selected as potential markers because their variable importance in projection (VIP) was greater than 1 in both models. The current study's findings lay a foundation for further research on the brown rice infestation mechanism and safe storage monitoring.
| S-EPMC9943867 | biostudies-literature
Project description:The main insect pest of stored paddy is Sitophilus oryzae (rice weevil). Huge amounts of rice are produced by peasant farmers each year, but the bulk of it is wasted due to insufficient storage facilities and insect pest attacks brought on by careless handling. In this study, the insecticidal effects of biochar on S. oryzae were assessed in femurs from Sus scrofa (pig), Gallus gallus (chicken), and Bos taurus (cattle). Adult mortality, adult emergence, weight loss, seed damage, and weevil perforation index are among the indicators evaluated. To apply the biochar, different dosages were used: 0.2, 0.4, 0.6, 0.8, and 1.0 g/20 g of paddy rice. In this work, the population of adult S. oryzae on paddy rice was dramatically reduced by all animal bones biochar tested for insecticidal activity (p < 0.05). The animal bone biochar became more effective with increasing dosage. After 24 h of treatment, pig biochar induced a 36.67 % mortality rate of adult S. oryzae, followed by cow biochar's 20 % mortality rate of rice weevils. The fatal dose of cattle, pig, and chicken biochar at which 50 % (LD50) of the population of adult S. oryzae responded after 24 h of treatment were 0.83g, 0.43g, and 0.90g, respectively. It should be encouraged to utilize biochar made from animal bones to combat the S. oryzae in stored paddy. They could be utilized as a green control measure to lessen the risk brought on by the usage of synthetic chemical insecticides in the environment.
| S-EPMC10864905 | biostudies-literature