The draft genome sequence of Xanthomonas species strain Nyagatare, isolated from diseased bean in Rwanda.

types: Journal ArticleThis is a pre-copyedited, author-produced PDF of an article accepted for publication in FEMS following peer review. The version of record Aritua, V., Musoni, A., Kabeja, A., Butare, L., Mukamuhirwa, F., Gahakwa, D., . . . Smith, J. (2015). The draft genome sequence of Xanthomonas species strain Nyagatare, isolated from diseased bean in Rwanda, FEMS Microbiology Letters, 2015, Vol. 362, No. 4 pp. 1-4 is available online at: http://femsle.oxfordjournals.org/content/362/4/1.1.exploreWe announce the genome sequence for Xanthomonas species strain Nyagatare, isolated from beans showing unusual disease symptoms in Rwanda. This strain represents the first sequenced genome belonging to an as-yet undescribed Xanthomonas species known as species-level clade 1. It has at least 100 kb of genomic sequence that shows little or no sequence similarity to other xanthomonads, including a unique lipopolysaccharide synthesis gene cluster. At least one genomic region appears to have been acquired from relatives of Agrobacterium or Rhizobium species. The genome encodes homologues of only three known type-three secretion system effectors: AvrBs2, XopF1 and AvrXv4. Availability of the genome sequence will facilitate development of molecular tools for detection and diagnostics for this newly discovered pathogen of beans and facilitate epidemiological investigations of a potential causal link between this pathogen and the disease outbreak.Canadian International Development AgencyBBSRC SCPRI

Risk Factors that Influence the Distribution and Acaricide Susceptibility of Ixodid Ticks Infesting Cattle in Rwanda

Information about acaricide classes to which ticks are tolerant or resistant to in Rwanda is mainly based on farmer reports of reduced susceptibility and scientific evidence is lacking. This study was designed with the aim of providing in-depth assessment of risk factors basing on acaricide use patterns and their association with distribution of ticks among cattle keepers in the Eastern and Western Provinces. A total of 976 cattle were searched for ticks by whole body search technique of which 205 were infested and 771 were not. Relative abundance of ticks significantly differed by province (χ2 =198, df =1, P< 0.05) and by district (χ2 = 271, df = 3, P < 0.05); of the 205 cattle infested by ticks, 175 (85%) were from the Eastern Province compared with only 30 (15)% cattle from the Western Province. Speciation of ticks showed only three species: Rhipicephalus appendiculatus (95.4%), Boophilus decolaratus (2.8%) and Amblyoma variegatum (1.6%). Genus Rhipicephalus was more abundant in the Eastern Province and Amblyoma in the Western Province; Boophilus was identified only in the Western Province. Acaricide type, frequency of use, area altitude and wash volume among other risk factors for acaricide tolerance/ resistance in ixodid ticks are discussed.Les informations sur les classes d’acaricides auxquels les tiques sont tolérantes ou résistantes au Rwanda sont principalement fondées sur les rapports des éleveurs faisant état d’une sensibilité réduite, mais les preuves scientifiques font défaut à ce sujet. La présente étude a été conçue dans le but de fournir une évaluation approfondie des facteurs de risque sur base des modes d’utilisation et de l’association des acaricides avec la répartition des tiques chez les bovins dans les provinces de l’Est et de l’Ouest. Au total, 976 bovins ont été examinés en vue de rechercher la présence de tiques, la méthode utilisée consistant à explorer tout le corps de l’animal. Cette méthode a révélé que 205 étaient infestés et que 771 ne l’étaient pas. L’abondance relative des tiques différait significativement selon la province (χ2 = 198, df = 1, P <0,05) et le district (χ2 = 271, df = 3, P <0,05). En effet, des 205 bovins infestés par les tiques, 175 (85%) provenaient de la province de l’Est, par rapport à 30 bovins seulement (15%) de la province de l’Ouest. La spéciation des tiques a révélé uniquement trois espèces: Rhipicephalus appendiculatus (95,4%), Boophilus decolaratus (2,8%) et Amblyoma variegatum (1,6%). Le genre Rhipicephalus était plus abondant dans la province de l’Est et Amblyoma dans la province de l’Ouest ; Boophilus a été identifié uniquement dans la province de l’Ouest. Le type d’acaricides, la fréquence de leur utilisation, l’altitude de la zone et le volume de lavage, entre autres facteurs de risque pour la tolérance / résistance aux acaricides chez les tiques ixodes, sont abordés.Mots-clés: résistance aux acaricides; classe des acaricides; espèces de tiques; bovin

An alternative strategy for sustainable pest resistance in genetically enhanced crops

Bacillus thuringiensis (Bt) crystal protein genes encode insecticidal -endotoxins that are widely used for the development of insect-resistant crops. In this article, we describe an alternative transgenic strategy that has the potential to generate broader and more sustainable levels of resistance against insect pests. Our strategy involves engineering plants with a fusion protein combining the -endotoxin Cry1Ac with the galactose-binding domain of the nontoxic ricin B-chain (RB). This fusion, designated BtRB, provides the toxin with additional, binding domains, thus increasing the potential number of interactions at the molecular level in target insects. Transgenic rice and maize plants engineered to express the fusion protein were significantly more toxic in insect bioassays than those containing the Bt gene alone. They were also resistant to a wider range of insects, including important pests that are not normally susceptible to Bt toxins. The potential impact of fusion genes such as BtRB in terms of crop improvement, resistance sustainability, and biosafety is discussed