Genetic diversity ofPuccinia kuehnii, the causal agent of orange rust of sugarcane, from Brazil

Autor(es)

Urashima, Alfredo Seiiti ^[1] ; Mistura, Tatiane de Fatima ^[1] ; Rodrigues Porto, Lis Natali ^[1] ; Austin, Paige Dariel ^[2] ; Arias, Renee Silvia ^[2]

Afiliação do(s) autor(es)

^[1] Univ Fed Sao Carlos, BR-13600000 Araras, SP - Brazil

^[2] ARS, USDA, South Atlantic Area Natl Peanut Res Lab, Dawson, GA - USA

• Tipo de documento: Artigo Científico
• Fonte: JOURNAL OF PHYTOPATHOLOGY; v. 168, n. 10 AUG 2020.
• Citações Web of Science: 0

Resumo

The use of resistant genotypes is the preferred method to control orange rust of sugarcane (Saccharumspp) caused byPuccinia kuehnii.This approach has been adopted in Brazil but outbreaks of the disease on previously resistant varieties showed that the efficacy of this method is limited and requires a better understanding of pathogen diversity. Nevertheless, adequate molecular markers for examining pathogen diversity at population level are not available, which limits the success of orange rust control by genetic resistance. Therefore, two independent investigations were conducted to examine genetic diversity ofP. kuehniifrom Sao Paulo state, the most important sugarcane growing state of Brazil. First, simple-sequence repeat (SSR) markers were developed in the present work and genotypic diversity of orange rust isolates from different locations investigated. Second, phenotypic diversity was examined by the single-pustule inoculation technique onP. kuehniiisolates retrieved from three susceptible commercial sugarcane cultivars. A total of 96 SSR markers were generated and tested for this species. Subsequently, 29 isolates ofP. kuehniiwere fingerprinted with nine SSR markers to estimate the genotypic diversity by neighbour-joining and 3D principal coordinates. The 29 isolates of the pathogen clustered into four main groups, which were identified by three SSR markers (NPRL\_PK\_108a, NPRL\_PK\_162\_spka and NPRL\_PK\_221\_spka). Phenotypic data at 21 days after the single-pustule inoculation showed thatP. kuehniifrom highly susceptible commercial cultivars harboured a small proportion of variants capable of causing disease on resistant cultivars. A differential reaction was demonstrated for the most virulent variant in a repeated experiment confirming the existence of races withinP. kuehniiin Brazil. (AU)

• Processo FAPESP: 17/14351-0 - Diversidade fenotípica e genotípica de Puccinia kuehnii, agente causal da ferrugem alaranjada, em um local de melhoramento de variedades de cana-de-açúcar
• Beneficiário: Lis Natali Rodrigues Porto
• Modalidade de apoio: Bolsas no Brasil - Iniciação Científica