scholarly journals Response of Selected Cassava Varieties to the Incidence and Severity of Cassava Brown Streak Disease in Tanzania

2012 ◽  
Vol 4 (7) ◽  
Author(s):  
Gration M. Rwegasira ◽  
Chrissie M. E. Rey
Keyword(s):  
Cassava Brown Streak Disease ◽  
Cassava Varieties ◽  
Brown Streak

scholarly journals The Symptom and Genetic Diversity of Cassava Brown Streak Viruses Infecting Cassava in East Africa

2012 ◽  
Vol 2012 ◽  
pp. 1-10 ◽  
Author(s):  
I. U. Mohammed ◽  
M. M. Abarshi ◽  
B. Muli ◽  
R. J. Hillocks ◽  
M. N. Maruthi
Keyword(s):  
Protein Gene ◽  
Virus Transmission ◽  
Eastern Africa ◽  
Cassava Brown Streak Disease ◽  
Complete Coat Protein ◽  
Reference Sequences ◽  
Virus Isolates ◽  
Cassava Varieties ◽  
Nicotiana Clevelandii ◽  
Brown Streak

The genetic and symptom diversity of six virus isolates causing cassava brown streak disease (CBSD) in the endemic (Kenya, Mozambique, and Tanzania) and the recently affected epidemic areas (Uganda) of eastern Africa was studied. Five cassava varieties; Albert, Colombian, Ebwanateraka, TMS60444 (all susceptible) and Kiroba (tolerant) were graft inoculated with each isolate. Based on a number of parameters including the severity of leaf and root symptoms, and the extent of virus transmission by grafting, the viruses were classified as either severe or relatively mild. These results were further confirmed by the mechanical inoculation of 13 herbaceous hosts in which the virulent isolates caused plant death inNicotiana clevelandiiandN. benthamianawhereas the milder isolates did not. Phylogenetic analysis of complete coat protein gene sequences of these isolates together with sequences obtained from 14 other field-collected samples from Kenya and Zanzibar, and reference sequences grouped them into two distinct clusters, representing the two species of cassava brown streak viruses. Put together, these results did not suggest the association of a hypervirulent form of the virus with the current CBSD epidemic in Uganda. Identification of the severe and milder isolates, however, has further implications for disease management and quarantine requirements.

scholarly journals PAL1 gene of the phenylpropanoid pathway increases resistance to the Cassava brown streak virus in cassava

2021 ◽  
Vol 18 (1) ◽  
Author(s):  
Siji Kavil ◽  
Gerald Otti ◽  
Sophie Bouvaine ◽  
Andrew Armitage ◽  
Midatharahally N. Maruthi
Keyword(s):  
Phenylpropanoid Pathway ◽  
Streak Virus ◽  
Rna Seq ◽  
Cassava Brown Streak Virus ◽  
Cassava Brown Streak Disease ◽  
Chalcone Synthase Genes ◽  
Increased Susceptibility ◽  
Cassava Varieties ◽  
Brown Streak

Abstract Background The phenylalanine ammonia lyase genes play crucial role in plant response to biotic and abiotic stresses. In this study, we characterized the role of PAL genes in increasing resistance to the Cassava brown streak virus that causes the economically important cassava brown streak disease (CBSD) on cassava in Africa. Methods The whole transcriptomes of eight cassava varieties differing in resistance to CBSD were obtained at 1, 5 and 8 weeks after CBSV infection. Results Analysis of RNA-Seq data identified the overexpression of PAL1, PAL2, cinnamic acid and two chalcone synthase genes in CBSD-resistant cassava varieties, which was subsequently confirmed by RT-qPCR. The exogenous application of Acibenzolar-S-Methyl induced PAL1 gene expression to enhance resistance in the susceptible var. Kalawe. In contrast, the silencing of PAL1 by RNA interference led to increased susceptibility of the resistant var. Kaleso to CBSD. Conclusions PAL1 gene of the phenylpropanoid pathway has a major role in inducing resistance to CBSD in cassava plants and its early induction is key for CBSD resistance.

scholarly journals Differential Tropism in Roots and Shoots of Resistant and Susceptible Cassava (Manihot esculenta Crantz) Infected by Cassava Brown Streak Viruses

Cells ◽  
2021 ◽  
Vol 10 (5) ◽  
pp. 1221
Author(s):  
Samar Sheat ◽  
Paolo Margaria ◽  
Stephan Winter
Keyword(s):  
Virus Replication ◽  
Central Africa ◽  
Streak Virus ◽  
Virus Infections ◽  
Long Distance ◽  
Manihot Esculenta Crantz ◽  
Cassava Brown Streak Virus ◽  
Cassava Brown Streak Disease ◽  
Long Distance Movement ◽  
Brown Streak

Cassava brown streak disease (CBSD) is a destructive disease of cassava in Eastern and Central Africa. Because there was no source of resistance in African varieties to provide complete protection against the viruses causing the disease, we searched in South American germplasm and identified cassava lines that did not become infected with the cassava brown streak viruses. These findings motivated further investigations into the mechanism of virus resistance. We used RNAscope® in situ hybridization to localize cassava brown streak virus in cassava germplasm lines that were highly resistant (DSC 167, immune) or that restricted virus infections to stems and roots only (DSC 260). We show that the resistance in those lines is not a restriction of long-distance movement but due to preventing virus unloading from the phloem into parenchyma cells for replication, thus restricting the virus to the phloem cells only. When DSC 167 and DSC 260 were compared for virus invasion, only a low CBSV signal was found in phloem tissue of DSC 167, indicating that there is no replication in this host, while the presence of intense hybridization signals in the phloem of DSC 260 provided evidence for virus replication in companion cells. In neither of the two lines studied was there evidence of virus replication outside the phloem tissues. Thus, we conclude that in resistant cassava lines, CBSV is confined to the phloem tissues only, in which virus replication can still take place or is arrested.

scholarly journals Field evaluation of selected cassava genotypes for cassava brown streak disease based on symptom expression and virus load

2014 ◽  
Vol 11 (1) ◽  
Author(s):  
Tadeo Kaweesi ◽  
Robert Kawuki ◽  
Vincent Kyaligonza ◽  
Yona Baguma ◽  
Geoffrey Tusiime ◽  
...  
Keyword(s):  
Field Evaluation ◽  
Symptom Expression ◽  
Virus Load ◽  
Cassava Brown Streak Disease ◽  
Brown Streak

scholarly journals Host and virus effects on reversion in cassava affected by cassava brown streak disease

2015 ◽  
Vol 65 (4) ◽  
pp. 593-600 ◽  
Author(s):  
I. U. Mohammed ◽  
S. Ghosh ◽  
M. N. Maruthi
Keyword(s):  
Cassava Brown Streak Disease ◽  
Brown Streak

Expansion of the cassava brown streak disease epidemic in eastern Democratic Republic of Congo

Plant Disease ◽  
2020 ◽  
Author(s):  
Clérisse Mubasi Casinga ◽  
Rudolph R Shirima ◽  
N M Mahungu ◽  
W Tata-Hangy ◽  
Kalinga Benoit Bashizi ◽  
...  
Keyword(s):  
Democratic Republic ◽  
Democratic Republic Of Congo ◽  
Smallholder Farmers ◽  
Central Africa ◽  
Virus Detection ◽  
Streak Virus ◽  
Republic Of Congo ◽  
Cassava Brown Streak Virus ◽  
Cassava Brown Streak Disease ◽  
Brown Streak

Cassava plays a key role in assuring food security and generating income for smallholder farmers throughout central Africa, and particularly in the Democratic Republic of Congo (DRC). This status is threatened, however, by cassava brown streak disease (CBSD) which has recently expanded its incidence and range in eastern DRC. The study described here, comprises the first extensive assessment of temporal change in occurrence of CBSD and its causal viruses in DRC, based on surveys conducted during 2016 and 2018. Cassava fields were inspected in Ituri, Nord-Kivu, Sud-Kivu, Tanganyika and Haut-Katanga provinces within eastern DRC, to record foliar incidence and severity of CBSD. Leaf samples were collected for virus detection and species-level identification. New occurrences of CBSD, confirmed by virus diagnostic tests, were recorded in two provinces (Haut-Katanga and Sud-Kivu) and nine previously unaffected territories, covering an area of > 62,000 km2, and at up to 900 km from locations of previously published reports of CBSD in DRC. Overall, average CBSD incidence within fields was 13.2% in 2016 and 16.1% in 2018. In the new spread zone of Haut-Katanga, incidence increased from 1.7% to 15.9%. CBSD is now present in provinces covering 321,000 km2 which is approximately 14% of the total area of DRC. This represents a major expansion of the CBSD epidemic, which was only recorded from one province (Nord-Kivu) in 2012. Both cassava brown streak virus (CBSV) and Ugandan cassava brown streak virus (UCBSV) were detected in Ituri, Nord-Kivu and Sud-Kivu, but only CBSV was detected in Haut-Katanga. Considered overall, these results confirm the increasing threat that CBSD poses to cassava production in DRC and describe an important expansion in the African pandemic of CBSD.

scholarly journals Cassava brown streak disease: a threat to food security in Africa

2015 ◽  
Vol 96 (5) ◽  
pp. 956-968 ◽  
Author(s):  
Basavaprabhu L. Patil ◽  
Edward Kanju ◽  
James P. Legg ◽  
Claude M. Fauquet
Keyword(s):  
Food Security ◽  
Cassava Brown Streak Disease ◽  
Brown Streak

scholarly journals RNAi-derived field resistance to Cassava brown streak disease persists across the vegetative cropping cycle

2013 ◽  
Vol 5 (1) ◽  
pp. 16-19 ◽  
Author(s):  
John Odipio ◽  
Emmanuel Ogwok ◽  
Nigel J Taylor ◽  
Mark Halsey ◽  
Anton Bua ◽  
...  
Keyword(s):  
Field Resistance ◽  
Cassava Brown Streak Disease ◽  
Brown Streak
Sign in / Sign up

Export Citation Format

Share Document