Publications by authors named "Leonardo Lima Pepino Macedo"

The cotton boll weevil (CBW, Anthonomus grandis) stands as one of the most significant threats to cotton crops (Gossypium hirsutum). Despite substantial efforts, the development of a commercially viable transgenic cotton event for effective open-field control of CBW has remained elusive. This study describes a detailed characterization of the insecticidal toxins Cry23Aa and Cry37Aa against CBW.

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Article Synopsis
  • - The sugarcane giant borer is a major pest that leads to significant losses in sugarcane crops, and traditional control methods like chemicals and manual efforts are largely ineffective.
  • - In this study, researchers evaluated the toxicity of four Cry toxins (Cry1A and Cry2Aa) on the borer's larvae, finding that Cry1Ac was the most effective, showing significantly higher activity compared to the other toxins.
  • - Molecular analysis identified potential interactions between Cry1Ac and specific receptors, suggesting that particular amino acids enhance the toxin's effectiveness, which could inform the development of genetically modified sugarcane resistant to this pest.
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The overexpression of the soybean GmEXPA1 gene reduces plant susceptibility to M. incognita by the increase of root lignification. Plant expansins are enzymes that act in a pH-dependent manner in the plant cell wall loosening and are associated with improved tolerance or resistance to abiotic or biotic stresses.

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The overexpression of the GmGlb1-1 gene reduces plant susceptibility to Meloidogyne incognita. Non-symbiotic globin class #1 (Glb1) genes are expressed in different plant organs, have a high affinity for oxygen, and are related to nitric oxide (NO) turnover. Previous studies showed that soybean Glb1 genes are upregulated in soybean plants under flooding conditions.

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pGhERF105 and pGhNc-HARBI1 promoters are highly responsive to CBW infestation and exhibit strong activity in vegetative and reproductive tissues, increasing their potential application in GM crop plants for pest control. The main challenge to cotton (Gossypium hirsutum) crop productivity is the constant attack of several pests, including the cotton boll weevil (CBW, Anthonomus grandis), which uses cotton floral buds for feeding and egg-laying. The endophytic nature of the early developmental stages of CBW makes conventional pesticide-based control poorly efficient.

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Meloidogyne incognita is the most economically important species of the root-knot nematode complex causing damage to several crops worldwide. During parasitism in host plants, M. incognita secretes several effector proteins to suppress the plant immune system, manipulate the plant cell cycle, and promote parasitism.

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Article Synopsis
  • The study presents a combined method of Agrobacterium and biolistics for transforming cotton into genetically modified (GM) varieties, addressing issues like pest losses and abiotic stresses.
  • The protocol involves several steps, including Agrobacterium preparation and embryo co-culture, and results in a high average transformation efficiency of 60% over a period of about 4-10 weeks.
  • The transgenic plants exhibit stable inheritance of the transgene, express it at high levels, and show no significant differences in traits or productivity compared to non-GM cotton plants.
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Article Synopsis
  • The Coffea arabica HB12 gene (CaHB12) enhances drought and salinity tolerance when overexpressed in plants, as shown in studies with Arabidopsis thaliana.
  • Transgenic cotton lines overexpressing CaHB12 demonstrated improved water use efficiency and photosynthetic yield under drought conditions compared to wild-type cotton.
  • Findings suggest that CaHB12 enhances the ABA-dependent signaling pathway, which helps plants better withstand water deficits and possibly prevents premature leaf dropping during stress.
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The cotton boll weevil, , is the most economically important pest of cotton in Brazil. Pest management programs focused on are based mostly on the use of chemical insecticides, which may cause serious ecological impacts. Furthermore, has developed resistance to some insecticides after their long-term use.

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RNA interference (RNAi)-mediated gene silencing can be used to control specific insect pest populations. Unfortunately, the variable efficiency in the knockdown levels of target genes has narrowed the applicability of this technology to a few species. Here, we examine the current state of knowledge regarding the miRNA (micro RNA) and siRNA (small interfering RNA) pathways in insects and investigate the structural variability at key protein domains of the RNAi machinery.

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The first successful attempt to generate genetically modified plants expressing a transgene was preformed via T-DNA-based gene transfer employing mediated genetic transformation. Limitations over infectivity and tissue culture led to the development of other DNA delivery systems, such as the biolistic method. Herein, we developed a new one-step protocol for transgenic soybean recovery by combining the two different transformation methods.

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Meloidogyne incognita is a plant-parasitic root-knot nematode (RKN, PPN) responsible for causing damage to several crops worldwide. In Caenorhabditis elegans, the DAF-16 and SKN-1 transcription factors (TFs) orchestrate aging, longevity, and defense responses to several stresses. Here, we report that MiDaf16-like1 and MiSkn1-like1, which are orthologous to DAF-16 and SKN-1 in C.

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The exploration of emerging host organisms for the economic and efficient production of protein microbicides against HIV is urgently needed in resource-poor areas worldwide. In this study, the production of the novel HIV entry inhibitor candidate, (GRFT), was investigated using as the expression platform based on a non-viral vector. To increase the yield of recombinant GRFT, the RNA silencing defense mechanism of was abolished by using three gene silencing suppressors.

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RNA interference (RNAi) approaches have been applied as a biotechnological tool for controlling plant insect pests via selective gene down regulation. However, the inefficiency of RNAi mechanism in insects is associated with several barriers, including dsRNA delivery and uptake by the cell, dsRNA interaction with the cellular membrane receptor and dsRNA exposure to insect gut nucleases during feeding. The cotton boll weevil (Anthonomus grandis) is a coleopteran in which RNAi-mediated gene silencing does not function efficiently through dsRNA feeding, and the factors involved in the mechanism remain unknown.

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Genetically modified (GM) cotton plants that effectively control cotton boll weevil (CBW), which is the most destructive cotton insect pest in South America, are reported here for the first time. This work presents the successful development of a new GM cotton with high resistance to CBW conferred by Cry10Aa toxin, a protein encoded by entomopathogenic Bacillus thuringiensis (Bt) gene. The plant transformation vector harbouring cry10Aa gene driven by the cotton ubiquitination-related promoter uceA1.

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Sugarcane is a widely cultivated plant that serves primarily as a source of sugar and ethanol. Its annual yield can be significantly reduced by the action of several insect pests including the sugarcane giant borer (Telchin licus licus), a lepidopteran that presents a long life cycle and which efforts to control it using pesticides have been inefficient. Although its economical relevance, only a few DNA sequences are available for this species in the GenBank.

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Background: Cotton is a major fibre crop grown worldwide that suffers extensive damage from chewing insects, including the cotton boll weevil larvae (Anthonomus grandis). Transcriptome analysis was performed to understand the molecular interactions between Gossypium hirsutum L. and cotton boll weevil larvae.

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Cotton plants are subjected to the attack of several insect pests. In Brazil, the cotton boll weevil, Anthonomus grandis, is the most important cotton pest. The use of insecticidal proteins and gene silencing by interference RNA (RNAi) as techniques for insect control are promising strategies, which has been applied in the last few years.

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