Pathogenicity of rice yellow mottle virus and screening of rice accessions from the Central African Republic

Abstract

BackgroundRice yellow mottle virus (RYMV) of the genus Sobemovirus is the most important viral pathogen of rice causing more damage to rice crop in Sub Saharan Africa. The aim of this study was to conduct pathogenic characterization of RYMV isolates from the Central African Republic (CAR) and to screen commonly cultivated rice accessions in the country for resistance/tolerance to the virus.MethodsThe pathogenicity of RYMV isolates was studied by mechanical inoculation with comparison to differential rice lines highly resistant to RYMV available at the Institute of Environment and Agricultural Research (INERA) in Burkina Faso.To screen commonly cultivated rice accessions in CAR, characterized RYMV isolates from the country were used as inoculum sources. Resistant breaking (RB) isolates were used to prepare RB-inoculum, whereas non-resistant breaking isolates (nRB) were used for nRB-inoculum.ResultsOverall 102 isolates used in this study, 29.4% were able to overcome the high resistance genes in the rice cultivars Gigante and Tog7291. All isolates were distributed within three distinct pathogenic profiles. The first profile constituted of 6.9% of the isolates was able to break down the resistance in rice cultivar Gigante only. The second pathogenic profile made of 19.6% of isolates was able to infect Tog7291 only. The third profile, 2.9% of isolates overcame simultaneously resistance genes in both rice cultivars Gigante and Tog7291. Out of isolates able to break down the resistance gene in cultivar Gigante, a single isolate was found to be non-infectious to the susceptible control IR64.Data from screening showed that all accessions were susceptible to RYMV, although IRAT213 was found to be partially resistant to both nRB-inoculum and RB-inoculum.ConclusionThe present study can be considered as the first in the Central African Republic, it gives a caution on the high risk of RYMV damage to rice production in the country. Beside, skills of pathogenic profiles of RYMV isolates will contribute to better disease management.Electronic supplementary materialThe online version of this article (10.1186/s12985-017-0912-4) contains supplementary material, which is available to authorized users.

Assessment of Korean rice lines for their reaction to rice yellow mottle virus in Ghana

“…genotypes had some level of resistance to RYMV, which disagrees with the overall susceptibility of rice genotypes to RYMV as reported by Sereme et al (2016) and Longue et al (2018). Among the five highly resistanct lines discovered in this study, two lines namely, 8261112 and 8261119, that did not show any symptoms have Nerica 8 as one of their parents.…”

“…About 170 lines representing 98.8% showed symptoms of RYMV disease and only 2 lines (genotypes 8261112 and 8261119) constituting 1.2% did not show any symptom of the disease at all. This confirms the scarcity of resistance to the disease as earlier reported (Longue et al, 2018;Sereme et al, 2016;Traore et al, 2015).…”

Genetic diversity of rice yellow mottle virus from Niger Office and Selingue Development Rural Office in Mali

“…Alkali et al (2015) and Issaka et al (2012) generated three groups using also serological technic with isolates collected from the northern of Nigeria and Niger. Isolates from Central Africa Republic were classified into three distinct pathogenic profiles by mechanical inoculation of six rice cultivars (Longue et al, 2018). According to Sérémé (2009), these different groups are related to the proteins involved in the mechanism of "silencing" to circumvent the defense system of the plant.…”

“…Due to frequent genetic mutations, microorganisms have the ability to adapt and grow within the new environments which facilitates their emergence at any time and becoming more virulent or more contagious (Hubert et al, 2017;Herzog, 2016). Virulent pathotypes overcoming one or two resistance alleles have been reported (Longue et al, 2018;Hebrad et al, 2018;Pidon et al, 2017;Pinel-Galzi et al, 2016). N'Guessan et al (2001) obtained two strains of RYMV at 6% divergence in nucleotide sequence of the capsid gene showing no difference in term of pathogenicity.…”

Genome editing of an African elite rice variety confers resistance against endemic and emergingXanthomonas oryzaepv.oryzaestrains

“…Today, African farmers, 90% of which are small-scale food producers with <1 ha of land (Pandey et al, 2010), produce ~60% of the local rice demand, but this demand will increase with the expected doubling of the population until 2050. Productivity is often hampered by the diseases Bacterial Leaf Blight (BB), Rice Yellow Mottle Virus (RYMV), and Rice Blast (RB)(Jiang et al, 2020; Longue et al, 2018; Mutiga et al, 2021). Breeding high-yielding varieties that are resistant to these diseases will be an important factor supporting food security in Africa.…”