Search results

Filters

  • Journals
  • Date

Search results

Number of results: 3
items per page: 25 50 75
Sort by:
Download PDF Download RIS Download Bibtex

Abstract

Tomato farms in Arusha, Morogoro, Dodoma, Iringa, Kilimanjaro and Coast regions of Tanzania were surveyed to assess the incidence of the yellow leaf curl disease, and to collect infected tomato leaf samples for sero-diagnosis. The triple antibody sandwich enzyme linked immunosorbent assay (TAS-ELISA) format was adopted for the detection of disease using commercial polyclonal antiserum and monoclonal antibodies SCRI 17, SCRI 20, SCRI 23 and SCRI 33. ELISA readings were rated on a scale of 0–4. The results of the tests indicated that all the Tomato yellow leaf curl virus (TY-LCV) isolates recorded high reaction values (4) with the polyclonal antibody. However, the Dodoma and Arusha isolates were rated highest in optical density (OD) reading with MAb SCRI 20 and 23. The remaining isolates produced lower OD values. All the isolates rated low (2) when tested with SCRI 33. The differences in reaction to the monoclonal antibodies of TYLCV indicated that variability exists between the coat protein epitopes of TYLCV and Tomato yellow leaf curl Tanzania virus (TYL-CTZV) on one hand, and among the TYLCTZV isolates on the other. Only the isolates from Arusha and Dodoma share a high sequence homology in coat protein with the European and related TYLCV isolates. Furthermore, the reaction with either SCRI 20 or SCRI 23 show that the isolates from Arusha and Dodoma share a high degree of homology, and could belong to one serotype. The other isolates from Morogoro, Coast and Kilimanjaro could form another serotype, while the isolate from Iringa is a different serotype. On the other hand, reaction with SCRI 17 groups the isolates in two serotypes, the Dodoma isolate alone, and another that groups the other five isolates together. It is recommended that other procedures such as DNA-DNA hybridization assays, polymerase chain reaction, restriction fragment length polymorphisms and sequencing can be combined with the use of monoclonal antisera for the detection and prediction or inference of Tomato yellow leaf curl disease (TYLCD) virus relationships at the quasi-species or strain levels in Tanzania.

Go to article

Authors and Affiliations

Boniface D. Kashina
Robert B. Mabagala
Anatolia A. Mpunami
Download PDF Download RIS Download Bibtex

Abstract

The tomato yellow leaf curl virus infecting tomato plants in Tanzania is reported to be different from the Old World geminiviruses. A study was initiated to investigate the transmission properties of the virus such as, acquisition feeding time, inoculation feeding time, persistence of virus in the vector, mechanical inoculation, seed and graft transmission. Results obtained indicate that the virus is transmitted persistently by Bemisia tabaci Genn., but neither mechanically – nor seed-transmissible. Minimum acquisition and inoculation time was 30 minutes. It is concluded that the properties of the agent causing the yellow leaf curl symptoms in tomato plants from different regions of Tanzania are similar and mimic those of tomato yellow leaf curl Begomovirus species studied elsewhere.

Go to article

Authors and Affiliations

Boniface D. Kashina
Robert B. Mabagala
Anatolia A. Mpunami
Download PDF Download RIS Download Bibtex

Abstract

Four tomato (Lycopersicon esculentum Mill.) varieties commonly grown by tomato farmers in Tanzania were evaluated for resistance to bacterial speck (Pseudomonas syringae pv. tomato) and bacterial spot (Xanthomonas vesicatoria) diseases, along with five introductions under screenhouse and field conditions. The four tomato varieties were Cal J, Moneymaker, Tanya and Roma VF. Seeds of the tomato varieties were purchased from seed vendors in the open market. The introductions that were included in the study were Bravo, Taxman, Stampede (from Sakata-Mayford Seeds (Pty) Ltd, South Africa), Torquay and BSS436 (from Bejo Zaden B.V., The Netherlands). In the screenhouse, results indicated that all the tomato varieties were susceptible to the two diseases, and suffered moderate to severe infection levels. The performance of the introductions against bacterial speck under screenhouse conditions was variable. All the introductions showed high levels of susceptibility to bacterial spot. Under field conditions, incidence of the diseases was high in all the locally available varieties tested, averaging 87% for bacterial spot and 82.3% for bacterial speck. The results of this study indicate that all the locally available tomato varieties included in the study were highly susceptible to bacterial speck and bacterial spot diseases.

Go to article

Authors and Affiliations

Kenneth C. Shenge
Robert B. Mabagala
Carmen N. Mortensen

This page uses 'cookies'. Learn more