Genetic variability of Puccinia triticina Eriks. in Brazil

Abstract

Studies on the genetic variability of Puccinia triticina in inoculum collected in Brazil started in 1941 with Vallega (20). The pioneering work in Brazil dates from 1949 (16) at "Instituto Agronômico do Sul", Ministry of Agriculture (MA), in Pelotas, Rio Grande do Sul State (RS), and continued after 1975 at Embrapa Wheat in Passo Fundo, RS. In 2002, analyses for the identification of P. triticina races continued at OR Seed breeding, simultaneously to Embrapa's program, both in Passo Fundo. The investigators involved in the identification of races in Brazil were Ady Raul da Silva in Pelotas (MA), Eliza Coelho in Pelotas (MA) and in Passo Fundo (Embrapa), Amarilis Labes Barcellos in Pelotas (MA) and in Passo Fundo (Embrapa and OR), Camila Turra in Passo Fundo (OR) and Marcia Chaves in Passo Fundo (Embrapa). From 1979 to 2010 growing season, 59 races were determined, according to the differentiation based on the expression of each Lr resistance gene. On average, one to three new races are detected per year. Research has focused on the use of vertical resistance; however, lately some institutes have searched more durable resistance, of the adult-plant type (horizontal, less race-specific). The uninterrupted monitoring of the wheat rust pathogenic population in Brazil during so many decades allowed the understanding of the evolution and virulence of races. The use of international nomenclature adopted by some programs has allowed the comparison of the fungus variability in Brazil with that in other countries, especially where frontiers are not barriers for spore transportation, confirmed by the occurrence of the same races all over one region.

Changes in gene expression profiles as they relate to the adult plant leaf rust resistance in the wheat cv. Toropi

“…Toropi was grown at 14 h light/10 h dark and 80% humidity until full expansion of the first flag leaf. Flag leaves were inoculated with urediniospores of P. triticina , race MDT-MR – Lr virulence: Lr1 , Lr3 , Lr3ka , Lr10 , Lr11 , Lr14a , Lr14b , Lr17 , Lr20 , Lr23 , Lr24 , Lr26 , Lr30 [14] – in a mineral oil suspension. Mock inoculations were carried out using the same mineral oil without urediniospores.…”

Exploring Durable Genetic Resistance against Leaf Rust through Phenotypic Characterization and Lr34Linked STS Marker in Wheat Germplasm

“…It breaks out during anthesis period at the time of grain formation and lasts long to inflict heavy damages to the yield if moderate temperature and high humidity is available (RATTU et al, 2010). The dynamic and rapid adaptation of its causative fungal pathogen (Puccinia triticina Erikss) conduce to a constant challenge of genetic resistance of the wheat cultivars, what is typically dependent on the effectiveness of the genes during the whole developmental cycle of the plant (BIANCHIN et al, 2012). To confront the challenge of rust, genetic resistance is the most effective, economical, longterm and environment friendly way instead of using expensive hazardous chemical applications (PINK, 2002;SHAH et al, 2014).…”