RESUMO
The western corn rootworm (WCR) Diabrotica virgifera virgifera (Coleoptera: Chrysomelidae) remains one of the economically most important pests of maize (Zea mays) due to its adaptive capabilities to pest management options. This includes the ability to develop resistance to some of the commercial pesticidal proteins originating from different strains of Bacillus thuringiensis. Although urgently needed, the discovery of new, environmentally safe agents with new modes of action is a challenge. In this study we report the discovery of a new family of binary pesticidal proteins isolated from several Chryseobacterium species. These novel binary proteins, referred to as GDI0005A and GDI0006A, produced as recombinant proteins, prevent growth and increase mortality of WCR larvae, as does the bacteria. These effects were found both in susceptible and resistant WCR colonies to Cry3Bb1 and Cry34Ab1/Cry35Ab1 (reassigned Gpp34Ab1/Tpp35Ab1). This suggests GDI0005A and GDI0006A may not share the same binding sites as those commercially deployed proteins and thereby possess a new mode of action. This paves the way towards the development of novel biological or biotechnological management solutions urgently needed against rootworms.
Assuntos
Bacillus thuringiensis , Chryseobacterium , Besouros , Praguicidas , Animais , Zea mays/genética , Chryseobacterium/metabolismo , Praguicidas/farmacologia , Endotoxinas/metabolismo , Proteínas de Bactérias/metabolismo , Plantas Geneticamente Modificadas/metabolismo , Besouros/genética , Larva/metabolismo , Bacillus thuringiensis/genética , Controle Biológico de Vetores , Resistência a InseticidasRESUMO
Hybrid wheat varieties give higher yields than conventional lines but are difficult to produce due to a lack of effective control of male fertility in breeding lines. One promising system involves the Rf1 and Rf3 genes that restore fertility of wheat plants carrying Triticum timopheevii-type cytoplasmic male sterility (T-CMS). Here, by genetic mapping and comparative sequence analyses, we identify Rf1 and Rf3 candidates that can restore normal pollen production in transgenic wheat plants carrying T-CMS. We show that Rf1 and Rf3 bind to the mitochondrial orf279 transcript and induce cleavage, preventing expression of the CMS trait. The identification of restorer genes in wheat is an important step towards the development of hybrid wheat varieties based on a CMS-Rf system. The characterisation of their mode of action brings insights into the molecular basis of CMS and fertility restoration in plants.
Assuntos
Cromossomos de Plantas/química , Genes Mitocondriais , Genes de Plantas , Infertilidade das Plantas/genética , RNA Mensageiro/genética , Triticum/genética , Sequência de Bases , Mapeamento Cromossômico , Citoplasma/genética , Citoplasma/metabolismo , Melhoramento Vegetal/métodos , Células Vegetais/química , Células Vegetais/metabolismo , Plantas Geneticamente Modificadas , Pólen/genética , Pólen/metabolismo , RNA Mensageiro/metabolismo , Triticum/metabolismoRESUMO
Motivation: The availability of databases identifying allergenic proteins via a transparent and consensus-based scientific approach is of prime importance to support the safety review of genetically-modified foods and feeds, and public safety in general. Over recent years, screening for potential new allergens sequences has become more complex due to the exponential increase of genomic sequence information. To address these challenges, an international collaborative scientific group coordinated by the Health and Environmental Sciences Institute (HESI), was tasked to develop a contemporary, adaptable, high-throughput process to build the COMprehensive Protein Allergen REsource (COMPARE) database, a publicly accessible allergen sequence data resource along with bioinformatics analytical tools following guidelines of FAO/WHO and CODEX Alimentarius Commission. Results: The COMPARE process is novel in that it involves the identification of candidate sequences via automated keyword-based sorting algorithm and manual curation of the annotated sequence entries retrieved from public protein sequence databases on a yearly basis; its process is meant for continuous improvement, with updates being transparently documented with each version; as a complementary approach, a yearly key-word based search of literature databases is added to identify new allergen sequences that were not (yet) submitted to protein databases; in addition, comments from the independent peer-review panel are posted on the website to increase transparency of decision making; finally, sequence comparison capabilities associated with the COMPARE database was developed to evaluate the potential allergenicity of proteins, based on internationally recognized guidelines, FAO/WHO and CODEX Alimentarius Commission.
RESUMO
The mariner-like transposon Mos1 is used for insertional mutagenesis and transgenesis in different animals (insects, nematodes), but has never been used in plants. In this paper, the transposition activity of Mos1 was tested in Nicotiana tabacum, but no transposition event was detected. In an attempt to understand the absence of in planta transposition, Mos1 transposase (MOS1) was produced and purified from transgenic tobacco (HMNtMOS1). HMNtMOS1 was able to perform all transposition reaction steps in vitro: binding to ITR, excision and integration of the same pseudo-transposon used in in planta transposition assays. The in vitro transposition reaction was not inhibited by tobacco nuclear proteins, and did not depend on the temperature used for plant growth. Several hypotheses are proposed that could explain the inhibition of HMNtMOS1 activity in planta.
