In vitro uptake of 140 kDa Bacillus thuringiensis nematicidal crystal proteins by the second stage juvenile of Meloidogyne hapla.

State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, China.
PLoS ONE (Impact Factor: 3.73). 01/2012; 7(6):e38534. DOI: 10.1371/journal.pone.0038534
Source: PubMed

ABSTRACT Plant-parasitic nematodes (PPNs) are piercing/sucking pests, which cause severe damage to crops worldwide, and are difficult to control. The cyst and root-knot nematodes (RKN) are sedentary endoparasites that develop specialized multinucleate feeding structures from the plant cells called syncytia or giant cells respectively. Within these structures the nematodes produce feeding tubes, which act as molecular sieves with exclusion limits. For example, Heterodera schachtii is reportedly unable to ingest proteins larger than 28 kDa. However, it is unknown yet what is the molecular exclusion limit of the Meloidogyne hapla. Several types of Bacillus thuringiensis crystal proteins showed toxicity to M. hapla. To monitor the entry pathway of crystal proteins into M. hapla, second-stage juveniles (J2) were treated with NHS-rhodamine labeled nematicidal crystal proteins (Cry55Aa, Cry6Aa, and Cry5Ba). Confocal microscopic observation showed that these crystal proteins were initially detected in the stylet and esophageal lumen, and subsequently in the gut. Western blot analysis revealed that these crystal proteins were modified to different molecular sizes after being ingested. The uptake efficiency of the crystal proteins by the M. hapla J2 decreased with increasing of protein molecular mass, based on enzyme-linked immunosorbent assay analysis. Our discovery revealed 140 kDa nematicidal crystal proteins entered M. hapla J2 via the stylet, and it has important implications in designing a transgenic resistance approach to control RKN.

  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Ascaris suum and Ascaris lumbricoides are two closely related geo-helminth parasites that ubiquitously infect pigs and humans, respectively. Ascaris suum infection in pigs is considered a good model for A. lumbricoides infection in humans because of a similar biology and tissue migration to the intestines. Ascaris lumbricoides infections in children are associated with malnutrition, growth and cognitive stunting, immune defects, and, in extreme cases, life-threatening blockage of the digestive tract and aberrant migration into the bile duct and peritoneum. Similar effects can be seen with A. suum infections in pigs related to poor feed efficiency and performance. New strategies to control Ascaris infections are needed largely due to reduced treatment efficacies of current anthelmintics in the field, the threat of resistance development, and the general lack of new drug development for intestinal soil-transmitted helminths for humans and animals. Here we demonstrate for the first time that A. suum expresses the receptors for Bacillus thuringiensis crystal protein and novel anthelmintic Cry5B, which has been previously shown to intoxicate hookworms and which belongs to a class of proteins considered non-toxic to vertebrates. Cry5B is able to intoxicate A. suum larvae and adults and triggers the activation of the p38 mitogen-activated protein kinase pathway similar to that observed with other nematodes. Most importantly, two moderate doses of 20 mg/kg body weight (143 nM/kg) of Cry5B resulted in a near complete cure of intestinal A. suum infections in pigs. Taken together, these results demonstrate the excellent potential of Cry5B to treat Ascaris infections in pigs and in humans and for Cry5B to work effectively in the human gastrointestinal tract.
    PLoS Neglected Tropical Diseases 06/2013; 7(6):e2263. · 4.57 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: The Bacillus thuringiensis subsp. sichuansis MC28 strain produces spherical parasporal crystals during sporulation and exhibits remarkable insecticidal activity against dipteran and lepidopteran pests. We characterized a novel cry gene (cry69Aa1), which was found in the pMC95 plasmid of the MC28 strain. The cry69Aa1 gene was inserted into a shuttle vector (pSTK) and expressed in an acrystalliferous mutant B. thuringiensis HD73(-). In this transformant, a large number of spherical parasporal crystals, which were toxic to Culex quinquefasciatus (Diptera), were formed.
    MIRCEN Journal of Applied Microbiology and Biotechnology 11/2013; · 1.08 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Plant parasitic nematodes are major threat for crop plants and cause severe economic losses worldwide annually. Various strategies deployed for the control of these notorious parasites has resulted either in limited success, or having huge negative impact on environment. RNA interference (RNAi) is a gene-silencing phenomenon that is conserved in various eukaryotes. Experimentally induced RNAi is highly specific and potent, leading to its wide utilization in functional studies for exploring gene functions. Crops engineered through RNAi have proven to be successful in protection against pest and parasites, including nematodes. Engineering nematode resistance in crop plants through host-derived RNAi is largely based on the selection of target gene. The expression of nematode specific dsRNA in plants generates siRNAs and taken up by nematodes on feeding. Depending upon the function, level of expression and silencing efficacy of the target gene, resistance was determined. RNAi seems to be promising in many aspects, such as providing durable resistance to crops against plant parasitic nematodes in the near future. In the present article, we have reviewed the published work on the host-derived RNAi for developing nematode resistance in plants. Copyright: © 2013 Tamilarasan S, et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
    Cell & Developmental Biology. 06/2013;

Full-text (3 Sources)

Available from
Jun 3, 2014