Rep-PCR reveals a high genetic homogeneity among Ugandan isolates of Xanthomonas campestris pv musacearum

Wilting of plants incited by a bacterium, Xanthomonas campestris pv musacearum (Xcm), was first described on Ensete (Ensete ventricosum) and later bananas (Musa species) in the highlands ofEthiopia in 1968. Although the spread outside Ethiopia remained unreported for several decades, an epidemic of the disease on banana in Uganda was observed in 2001, in the districts of Mukono andKayunga. Since then, the disease has spread into almost three quarters of the major banana growing areas in Uganda. It has also been confirmed affecting banana plantations in the Democratic Republic ofCongo (DRC) and Rwanda. Repetitive sequence based genomic fingerprinting that uses a PCRmediated amplification of DNA sequences located between specific interspersed sequences of highlyconserved elements in prokaryotic genomes was used to characterize a collection of Xcm isolates from banana in Uganda. Fingerprints of bacterial isolates collected from Xcm symptom bearing bananaplants grown in production fields from 10 districts including Kayunga, Masindi, Luwero, Kampala, Kiboga, Lira, Wakiso, Kibale and Nakasongola revealed similar patterns. Cluster analysis of pair wisesimilarity values performed using unweighted pair group method with arithmetic averages clustering technique did not generate any differences in the fingerprint patterns either. The implications of thisgenetic homogeneity on the origin and management of Xcm is discussed here

REACTION OF Musa balbisiana TO BANANA BACTERIAL WILT NFECTION

Banana bacterial wilt ( Xanthomonas campestris ) is an emerging disease of bananas in Uganda. All banana cultivars grown are susceptible. Musa balbisiana , a wild banana relative exhibits a progenitor like resistance type reaction to banana bacterial wilt infection. The negative M. balbisiana disease reaction suggests it could be used to improve banana resistance to banana bacterial wilt disease. Screenhouse and field experiments were used to characterise the reaction of M. balbisiana to banana bacterial wilt infetion. Psang awak, a reference susceptible cultivar was used as a positive control. No disease development on M. balbisiana under field and controlled conditions was observed. In general, as early as two weeks after inoculation, significant differences (P<0.05) were observed between M. balbisiana and the susceptible banana cultivar, Psang awak (ABB). Time course analysis of the possible role of Pathogenesis related protein 2 (PR-2), Phenyl alanine ammonia lyase (PAL), Non-expressor of pathogenesis related gene (NPR1) genes in Musa balbisiana resistance reactions, revealed that only NPR1 was expressed 15 days after inoculation with X. campestris at 108 dosage. The expression of NPR1, a marker gene of the systemic acquired resistance plant defence system provides preliminary evidence that this may be the major form of resistance in Musa balbisiana to bacterial wilt infection.Le fl\ue9trissement bact\ue9rien du bananier ( Xanthomonas campestris ) est une maladie \ue9mergente en Uganda, o\uf9 tous les cultivars en sont susceptibles. Musa balbisiana , un bananier relatif sauvage manifeste un type de r\ue9action de r\ue9sistance prog\ue9nitrice \ue0 l\u2019infection due au fl\ue9trissement bact\ue9rien. La r\ue9action n\ue9gative de M. balbisiana \ue0 la maladie sugg\ue8re que ceci pourrait \ueatre utilis\ue9 pour am\ue9liorer la r\ue9sistance du bananier cette maladie. Des essais en serre et en champs \ue9taient conduits pour caract\ue9riser la r\ue9action de M. balbisiana \ue0 l\u2019infection du bananier par le fl\ue9trissement bact\ue9rien. Le Psang awak, un cultivar susceptible de r\ue9ference \ue9tait utils\ue9 comme t\ue9moins positif. Aucun signe de d\ue9veloppement de la maladie n\u2019\ue9tait observ\ue9 sur M. balbisiana dans les deux milieux en champs et en serre. En g\ue9n\ue9ral, des diff\ue9rences significatives (P<0.05) \ue9taient observ\ue9es plus t\uf4t avant deux semaines apr\ue8s inoculation entre M. balbisiana et le cultivar de bananier susceptible, Psang awak (ABB). L\u2019analyse du temps de d\ue9roulement du r\uf4le possible de la pathogen\ue8se li\ue9e \ue0 la prot\ue9ine 2 (PR-2), \ue0 la Ph\ue9nyl alanine ammonia lyase (PAL), \ue0 la non-expression de la pathogen\ue8se li\ue9e au g\ue9ne (NPR1) de r\ue9sistance exprim\ue9e par Musa balbisiana, a r\ue9v\ue9l\ue9 que seulement NPR1 s\u2019\ue9tait exprim\ue9 15 jours apr\ue8s inoculation du X. campestris au dosage de 108. L\u2019expression de NPR1, un marqueur de g\ue8ne de r\ue9sistance acquis du syst\ue8me de d\ue9fence des plantes fournit une \ue9vidence que ceci serait une forme majeur de r\ue9sistance du Musa balbisiana \ue0 l\u2019infection du fl\ue9trissement bact\ue9rien

EFFICACY OF REHABILITATION METHODS ON CITRUS CANKER DISEASE IN NORTHERN UGANDA

Citrus ( Citrus sinensis ) is an important crop in Uganda, where it is produced for both domestic consumption and regional markets. Unfortunately it is increasingly devastated by canker disease. Several measures are often recommended for citrus canker management worldwide; the major ones being orchard inspection, quarantines, protective copper sprays and the on-site burning of infected trees. The adoption rate for these options in Northern Uganda has not been possible and as a result, the disease has reached epiphytotic level. Cultural practices and phytosanitary measures, consisting of removal of inoculum sources, timely application of protective chemical sprays and field sanitation could restore citrus orchards in areas affected by citrus canker. This study was carried out to determine the most effective method of eliminating inoculum sources and appropriate chemical sprays after inoculum suppression, to prevent re-infection. On-station trials were carried out in three fields (orchards), with 90-100% of trees infected at the beginning of the experiment. Treatments evaluated were: (i) bark horning during the dry season, (ii) bark horning during the wet season, and (iii) protective copper sprays. Each orchard was divided into three portions and each portion consisted of a minimum of 10 trees. For each orchard, one portion received bark horning treatment during the wet season (November) and the other portion during the dry season (December). The third portion was treated with 0.2% copper oxychloride. Inspection and removal of twigs emerging with symptoms two months after bark horning treatment, application of protective copper and insecticide sprays two, three and four months after bark horning were administered as a follow up treatments to bark horning. The effect of treatments on citrus canker incidence was significant (P<0.05). The incidence of re-infection was highest in plots that were bark horned during the wet season (23.4%), and lowest in plots bark horned during the dry season (3.3%). Complete bark horning of infected orchards at the beginning of dry season, followed by at least 6 months of regular orchard inspection; removal of re-infected branches and judicious application of chemical sprays (copper oxychloride fungicide and pyrinex insecticide) was the best option for managing citrus canker disease. Use of cultural practice and phytosanitary measures is, hence, recommended.Le citronnier ( Citrus sinensis ) est une culture importante en Ouganda, o\uf9 il est produit pour la consommation domestique et pour des march\ue9s r\ue9gionaux. Malheureusement, il est de plus en plus d\ue9vast\ue9 par la maladie du chancre. Plusieurs mesures sont souvent recommand\ue9es pour le contr\uf4le du chancre du citronnier dans le monde, entre autre les plus importantes sont l\u2019inspection des vergers, la mise en quarantaine, pulv\ue9risation protective du cuivre et l\u2019incin\ue9ration des arbres infect\ue9s. L\u2019adoption de ces pratiques au nord de l\u2019Ouganda n\u2019a pas \ue9t\ue9 possible, et en cons\ue9quence, la maladie a atteint un niveau \ue9piphytotique. Ces pratiques culturales et mesures phytosanitaires consistant \ue0 l\u2019enl\ue8vement des sources d\u2019inoculum, application opportune des produits chimiques de pulv\ue9risation et la sanitation du champ pourraient restaurer les vergers de citronniers dans les milieux affect\ue9s par le chancre du citronnier. Cette \ue9tude \ue9tait conduite pour d\ue9terminer la m\ue9thode la plus efficace pour l\u2019enl\ue8vement des sources d\u2019inoculum et les produits chimiques appropri\ue9s de pulv\ue9risation apr\ue8s l\u2019enl\ue8vement de l\u2019inoculum, afin de s\u2019assurer que les vergers ne seront plus r\ue9infect\ue9s. Des essais en station \ue9taient utilis\ue9s pour \ue9valuer les syst\ue8mes de gestion int\ue9gr\ue9e du chancre du citronnier. Ces essais \ue9taient conduits dans vergers, avec 90-100% d\u2019arbres infectes au d\ue9but de l\u2019exp\ue9rimentation. Les traitements incluaient: (i) bark horning pendant la saison s\ue8che, (ii) bark horning pendant la saison humide, et (iii) pulv\ue9risation protective du cuivre. Chaque verger \ue9tait subdivis\ue9 en trois parties et chaque partie contenait un minimum de dix arbres. Chaque partie de chaque verger avait re\ue7u un traitement de bark horning pendant la saison humide (Novembre) et l\u2019autre portion durant la saison s\ue8che (D\ue9cembre). La troisi\ue8me partie \ue9tait trait\ue9e avec 0.2% de l\u2019oxychlorure de cuivre. L\u2019inspection et l\u2019enl\ue8vement des brindilles poussant avec sympt\uf4mes deux mois apr\ue8s le traitement du bark horning, application protective du cuivre et la deuxi\ue8me pulv\ue9risation d\u2019insecticide, trois et quatre mois apr\ue8s l\u2019administration du bark horning comme traitements de suivi du bark horning. L\u2019effet de traitements sur le chancre du citronnier \ue9tait significatif (P<0.05). L\u2019incidence de la r\ue9infection \ue9tait la plus \ue9lev\ue9e dans les parcelles trait\ue9es avec le bark horn pendant la saison humide (23.4%), et moins \ue9lev\ue9e dans celles trait\ue9es avec le bark horn pendant la saison s\ue8che (3.3%). Un traitement complet au bark horn des vergers infect\ue9s au d\ue9but de la saison humide, suivi d\u2019au moins six mois d\u2019inspection r\ue9guli\ue8re de verger, l\u2019enl\ue8vement des branches r\ue9infect\ue9es et une application judicieuse des pulv\ue9risation chimiques (fongicide du chlorure de cuivre et insecticide pyrinex) \ue9tait la meilleur option pour la gestion du chancre du citronnier. L\u2019utilisation de la pratique culturale et les mesures phytosanitaires, et ainsi recommand\ue9e

EFFICIENT SCREENING PROCEDURE FOR BLACK SIGATOKA DISEASE OF BANANA

Current methods for screening for reaction of Mycosphaerella fijiensis are mostly field based and subject to variability caused by weather conditions. The objective of this study was to develop an efficient screening procedure for black sigatoka disease in order to provide a reliable controlled environment screening method. A fragmented mycelia-based infection system was developed using weighed mycelia suspensions, in 0.18% water agar. Consistent and repeatable black sigatoka infection was achieved in cv. Gross Michel as a reference susceptible cultivar. The infection system developed was used to validate screenhouse reaction of banana genotypes to M. fijiensis. Three East African highland genotypes (AAA-EA), one plantain genotype (ABB), two dessert (AAB and AAA) and one hybrid genotype (AAAA) were tested. Inoculum of M. fijiensis was adjusted to 15 mg ml-1 fragmented mycelium and applied to the abaxial surfaces of the first two open leaves. Plants were evaluated for 6 weeks post inoculation (PI). Significant differences in the response of the different genotypes, to M. fijiensis infection were observed at 3, 4, 5 and 6 weeks PI. All East African highland and dessert genotypes were susceptible. M9 hybrid and Psang awak (ABB) expressed resistance, characterised by high disease incubation period and slow rate of symptom development, with Psanag awak being the most resistant. Artificial inoculation of in vitro plants with weighed fragmented mycelial suspension, was practicable for determining resistance to M. fijiensis. This is the first report demonstrating that use of weighed fragmented mycelial inoculum spread over the entire leaf surface, can be used to quantitatively assess reaction of banana genotypes to M. fijiensis under screenhouse conditions.Les m\ue9thodes actuelles de d\ue9pistage de Mycosphaerella fijiensis sont essentiellement bas\ue9es sur des \ue9valuations dans le champ et sont souvent sujets \ue0 des variabilit\ue9s climatiques. L\u2019objectif de cette \ue9tude \ue9tait de d\ue9velopper une proc\ue9dure efficace de d\ue9pistage de la maladie foliaire du bananier Sigatoka dans le but de proposer une m\ue9thode de d\ue9pistage non influenc\ue9e par l\u2019environnement. Un syst\ue8me d\u2019infection a \ue9t\ue9 d\ue9velopp\ue9 en se servant de myc\ue9lium en suspension dans 0,18% de solution agar. Des infections consistantes et r\ue9p\ue9t\ue9es ont \ue9t\ue9 r\ue9alis\ue9es in cv. La vari\ue9t\ue9 Gross Michel a \ue9t\ue9 utilis\ue9e comme r\ue9f\ue9rence susceptible. Le syst\ue8me d\u2019infection d\ue9velopp\ue9 a \ue9t\ue9 utilis\ue9 pour valider la r\ue9action des accessions de bananiers en serre \ue0 M. fijiensis. Trois g\ue9notypes de bananiers adapt\ue9s aux hautes altitudes en Afrique de l\u2019Est (AAA-EA), un g\ue9notype de type plantain (ABB), deux d\ue9serts (AAB and AAA) et un hybride (AAAA) ont \ue9t\ue9 test\ue9s. Des inocula de M. fijiensis ont \ue9t\ue9 doses \ue0 15 mg ml-1 et appliqu\ue9s sur la face dorsale des deux premi\ue8res feuilles ouvertes. Les plants ont \ue9t\ue9 \ue9valu\ue9s pendant 6 semaines apr\ue8s inoculation (PI). Des diff\ue9rences significatives ont \ue9t\ue9 observ\ue9es dans les r\ue9ponses des g\ue9notypes \ue0 l\u2019infection \ue0 diff\ue9rents stages apr\ue8s inoculation (3, 4,5 et 6 semaines) de M. fijiensis. Tous les g\ue9notypes de haute altitude et les d\ue9serts ont \ue9t\ue9 r\ue9v\ue9l\ue9s susceptibles. L\u2019hybride M9 et Psang awak (ABB) se sont montr\ue9s r\ue9sistants, ils sont caract\ue9ris\ue9s par une longue p\ue9riode d\u2019incubation et un taux bas de d\ue9veloppement de sympt\uf4mes, Psanag awak s\u2019est r\ue9v\ue9l\ue9 le plus r\ue9sistant. L\u2019inoculation artificielle in vitro des plants avec des suspensions de fragments myc\ue9liens, a \ue9t\ue9 pratique dans la d\ue9termination de la r\ue9sistance \ue0 M. fijiensis. Ceci est le premier r\ue9sultat d\u2019\ue9tude scientifique ayant d\ue9montr\ue9 que cette technique peut \ueatre utilis\ue9e pour l\u2019\ue9valuation de la r\ue9action des g\ue9notypes de bananiers \ue0 l\u2019infection de M. fijiensis dans des conditions d\u2019exp\ue9riences en serre.

Plant extracts as potential control agents of Black Sigatoka in banana

Aqueous extracts of Cinnamomum zeylanicum, Capsicum annuum and Azadirachta indica were tested for efficacy for management of Pseudocercospora fijiensis in banana (Musa spp.) when applied as foliar sprays. Extracts of C. annuum and A.indica demonstrated fungicidal effects in vitro, without showing phytotoxic effects. The two extracts protected tissue culture banana plantlets of cultivar Musakala to a similar degree as the traditional fungicide difenoconazole. Extracts of A. indica and C. annuum (0.3 g/ml) reduced Black Sigatoka severity by 69.3% and 65.6%, respectively, and were thus comparable to the fungicide difenoconazole (72.7%). Soil drenching of the extracts did not significantly reduce Black Sigatoka severity. In planta effects of the extracts mainly consisted of delayed symptom appearance and reduced lesion number. Symptom development was dependent on extract concentration and days between extract application and inoculation. Effect of the tested extracts on height of plants and new leaves was not significant. Collectively, our data suggest that A. indica and C. annuum have interesting and unique properties as plant protection agents against Pseudocercospora fijiensis, but further research is needed to investigate their efficacy

REACTION OF Musa balbisiana TO BANANA BACTERIAL WILT NFECTION

Banana bacterial wilt ( Xanthomonas campestris ) is an emerging disease of bananas in Uganda. All banana cultivars grown are susceptible. Musa balbisiana , a wild banana relative exhibits a progenitor like resistance type reaction to banana bacterial wilt infection. The negative M. balbisiana disease reaction suggests it could be used to improve banana resistance to banana bacterial wilt disease. Screenhouse and field experiments were used to characterise the reaction of M. balbisiana to banana bacterial wilt infetion. Psang awak, a reference susceptible cultivar was used as a positive control. No disease development on M. balbisiana under field and controlled conditions was observed. In general, as early as two weeks after inoculation, significant differences (P<0.05) were observed between M. balbisiana and the susceptible banana cultivar, Psang awak (ABB). Time course analysis of the possible role of Pathogenesis related protein 2 (PR-2), Phenyl alanine ammonia lyase (PAL), Non-expressor of pathogenesis related gene (NPR1) genes in Musa balbisiana resistance reactions, revealed that only NPR1 was expressed 15 days after inoculation with X. campestris at 108 dosage. The expression of NPR1, a marker gene of the systemic acquired resistance plant defence system provides preliminary evidence that this may be the major form of resistance in Musa balbisiana to bacterial wilt infection.Le flétrissement bactérien du bananier ( Xanthomonas campestris ) est une maladie émergente en Uganda, où tous les cultivars en sont susceptibles. Musa balbisiana , un bananier relatif sauvage manifeste un type de réaction de résistance progénitrice à l’infection due au flétrissement bactérien. La réaction négative de M. balbisiana à la maladie suggère que ceci pourrait être utilisé pour améliorer la résistance du bananier cette maladie. Des essais en serre et en champs étaient conduits pour caractériser la réaction de M. balbisiana à l’infection du bananier par le flétrissement bactérien. Le Psang awak, un cultivar susceptible de réference était utilsé comme témoins positif. Aucun signe de développement de la maladie n’était observé sur M. balbisiana dans les deux milieux en champs et en serre. En général, des différences significatives (P<0.05) étaient observées plus tôt avant deux semaines après inoculation entre M. balbisiana et le cultivar de bananier susceptible, Psang awak (ABB). L’analyse du temps de déroulement du rôle possible de la pathogenèse liée à la protéine 2 (PR-2), à la Phényl alanine ammonia lyase (PAL), à la non-expression de la pathogenèse liée au géne (NPR1) de résistance exprimée par Musa balbisiana, a révélé que seulement NPR1 s’était exprimé 15 jours après inoculation du X. campestris au dosage de 108. L’expression de NPR1, un marqueur de gène de résistance acquis du système de défence des plantes fournit une évidence que ceci serait une forme majeur de résistance du Musa balbisiana à l’infection du flétrissement bactérien

Reaction of banana germplasm to inoculation with Xanthomonas campestris pv musacearum

No Abstract

Reaction of Banana Germplasm to Inoculation with Xanthomonas campestris pv. musacearum

Pot trial to evaluate the reaction of Uganda&apos;s local banana germplasm to artificial inoculation with Xanthomonas campestris pv. musacearum (Xcm) was established in 2004 and 2005 in Mukono district, Uganda. X. campestris pv musacearum causes infection causes premature fruit ripening and leaf wilting, killing every affected plant hence leading to total yield loss. The disease is managed through cultural practices but it was thought that use of resistant varieties would provide a better management option. Potted plants in a farmer&apos;s field were therefore inoculated with a bacterial suspension containing 1x108 bacterial cells/mL of Xcm. 1mL of bacterial suspension was injected into the petiole of the youngest open leaf using a hypodermic needle. Twenty five plants of each of the 42 banana genotypes were involved in the study. Wilt disease developed in the three months old banana plantlets of all local germplasm tested except for Musa balbsiana

A systematic review of the effectiveness of mental health promotion interventions for young people in low and middle income countries.

BACKGROUND: This systematic review provides a narrative synthesis of the evidence on the effectiveness of mental health promotion interventions for young people in low and middle-income countries (LMICs). Commissioned by the WHO, a review of the evidence for mental health promotion interventions across the lifespan from early years to adulthood was conducted. This paper reports on the findings for interventions promoting the positive mental health of young people (aged 6-18 years) in school and community-based settings. METHODS: Searching a range of electronic databases, 22 studies employing RCTs (N = 11) and quasi-experimental designs conducted in LMICs since 2000 were identified. Fourteen studies of school-based interventions implemented in eight LMICs were reviewed; seven of which included interventions for children living in areas of armed conflict and six interventions of multicomponent lifeskills and resilience training. Eight studies evaluating out-of-school community interventions for adolescents were identified in five countries. Using the Effective Public Health Practice Project (EPHPP) criteria, two reviewers independently assessed the quality of the evidence. RESULTS: The findings from the majority of the school-based interventions are strong. Structured universal interventions for children living in conflict areas indicate generally significant positive effects on students' emotional and behavioural wellbeing, including improved self-esteem and coping skills. However, mixed results were also reported, including differential effects for gender and age groups, and two studies reported nonsignficant findings. The majority of the school-based lifeskills and resilience programmes received a moderate quality rating, with findings indicating positive effects on students' self-esteem, motivation and self-efficacy. The quality of evidence from the community-based interventions for adolescents was moderate to strong with promising findings concerning the potential of multicomponent interventions to impact on youth mental health and social wellbeing. CONCLUSIONS: The review findings indicate that interventions promoting the mental health of young people can be implemented effectively in LMIC school and community settings with moderate to strong evidence of their impact on both positive and negative mental health outcomes. There is a paucity of evidence relating to interventions for younger children in LMIC primary schools. Evidence for the scaling up and sustainability of mental health promotion interventions in LMICs needs to be strengthened