Resistance to Rice yellow mottle virus in rice germplasm in Madagascar

• Published in: European journal of plant pathology Vol. 122; no. 2; pp. 277 - 286
• Main Authors: Rakotomalala, M., Pinel-Galzi, A., Albar, L., Ghesquière, A., Rabenantoandro, Y., Ramavovololona, P., Fargette, D.
• Format: Journal Article
• Language: English
• Published: Dordrecht Springer Netherlands 01.10.2008; Springer; Springer Nature B.V; Springer Verlag
• Subjects: Agriculture; Biological and medical sciences; Biomedical and Life Sciences; Crop diseases; Crop production; Cultivars; Ecology; Fundamental and applied biological sciences. Psychology; Life Sciences; Phytopathology and phytopharmacy; Phytopathology. Animal pests. Plant and forest protection; Plant breeding; Plant Pathology; Plant reproduction; Plant resistance; Plant Sciences; Plant viruses and viroids; Rice; Vegetal Biology; Viruses; Recessive resistance; Resistance-breaking pathotypes; Participatory plant breeding; Virus; Resistance; Plant pathology; Plant; Rice yellow mottle virus; Sobemovirus; Microbiology; Plant pathogen; Pathotype
• ISSN: 0929-1873; 1573-8469
• DOI: 10.1007/s10658-008-9282-5

Rice yellow mottle virus (RYMV) is a recent and major threat to rice production in Madagascar. A large scale screening of resistance to RYMV in rice germplasm in Madagascar was conducted by visual symptom scoring and virus-assessment through ELISA tests. The response to virus inoculation of 503 local or introduced rice accessions was assessed. Most of them were susceptible to RYMV. A few cultivars expressed partial resistance at a level similar to the partially resistant Oryza sativa japonica cv. Azucena. Only one O. sativa cultivar expressed high resistance characterised by a lack of symptoms and an undetectable level of virus. It was a Malagasy traditional indica cultivar, named Bekarosaka, which originated from the northwest of the country. It was selected by farmers for its field resistance to RYMV. The response of cv. Bekarosaka to four pathotypes of RYMV was similar to that of cv. Gigante, the only other highly resistant indica cultivar. The sequence of the middle domain of the eIF(iso)4G, the genetic determinant of Rymv1 resistance on chromosome 4, of cv. Bekarosaka was similar to that of cv. Gigante. Subsequently, cvs Bekarosaka and Gigante probably carried the same resistance allele Rymv1-2 . Rymv1- 2 resistance was efficient against isolates of the major strains of RYMV, but was readily overcome by a pathotype from the northwest of Madagascar.