Bru1 gene and potential alternative sources of resistance to sugarcane brown rust disease

• Published in: Euphytica Vol. 191; no. 3; pp. 429 - 436
• Main Authors: Racedo, Josefina, Perera, María F., Bertani, Romina, Funes, Claudia, González, Victoria, Cuenya, María I., D′Hont, Angélique, Welin, Björn, Castagnaro, Atilio P.
• Format: Journal Article
• Language: English
• Published: Dordrecht Springer Netherlands 01-06-2013; Springer; Springer Nature B.V
• Subjects: Agronomy. Soil science and plant productions; Biological and medical sciences; Biomedical and Life Sciences; Biotechnology; Breeding; Diagnosis; Disease susceptibility; Food processing industry; Fundamental and applied biological sciences. Psychology; Fungi; Generalities. Genetics. Plant material; Genes; Genetic resources; Genetic resources, diversity; Genetics and breeding of economic plants; Genotypes; High pressure; Life Sciences; Molecular biology; Plant diseases; Plant Genetics and Genomics; Plant material; Plant Pathology; Plant Physiology; Plant Sciences; Puccinia melanocephala; Resistance to control; Sugarcane; 1; Disease resistance; Molecular markers; Genetic resources; Saccharum; Monocotyledones; Plant pathogen; Genetic resource; Parasitic rust; Molecular marker; Sugar plant; Basidiomycota; Fungi; Bru1; Gene; Gramineae; Puccinia melanocephala; Angiospermae; Genetic improvement; Spermatophyta; Sugar cane
• ISSN: 0014-2336; 1573-5060
• DOI: 10.1007/s10681-013-0905-3

Brown rust, caused by the fungus
Puccinia melanocephala
, is responsible for important yield losses in sugarcane production globally and it is therefore an important objective to introduce resistance to this disease in breeding programs. A major gene,
Bru
1, has been shown to confer resistance to
P.
melanocephala
strains from different parts of the world and two molecular markers, R12H16 and 9O20-F4, closely associated to this gene have been previously reported. The usefulness of these molecular diagnostic markers in order to predict a rust resistant phenotype under natural high pressure inoculums conditions was analyzed. A total of 129 sugarcane accessions were evaluated under field infection for resistance or susceptibility to brown rust and subsequently screened for presence or absence of the two
Bru
1 diagnostic markers. A total of 49 genotypes (38 %) were phenotyped as resistant to brown rust but only eight (16.3 %) of them were harboring the
Bru
1 gene. To determine overall frequency of the
Bru
1 in the local sugarcane germplasm collection, 190 additional genotypes were examined. Presence of
Bru
1, as determined by the diagnostic markers, was detected in only 7 % of the genotypes evaluated. In conclusion,
Bru
1 diagnostic markers enable positive selection for brown rust resistance in sugarcane and moreover allowed detecting at least one additional source(s) of resistance. Interestingly, whilst only little genetic variability of rust resistance independent of
Bru
1 has been reported previously, this alternative genetic resource(s) found in our local germplasm constitutes the predominant one and should be helpful in order to amplify the narrow genetic basis for brown rust resistance in sugarcane.