Genetic and Molecular Basis of Wheat-Magnaporthe oryzae Triticum Interaction

Jessica Rosset Ferreira, Cisele Abigail Montan Torres, Luciano Consoli, Eliseu Binneck, Cabriela Andriolio Camilotti, Sandra Maria Mansur Scagliusi, Carolina Cardoso Deuner, Alexei de Campos Dianese, Augusto Cesar Pereira Coulart, Claudine Dinali Santos Seixas and Mauricio Antonio de Oliveira Coelho

CONTENTS

  • 5.1 Introduction....................................................................................................69
  • 5.2 Genetic Resistance..........................................................................................70
  • 5.3 BRS 209 x CBFusarium ENT014 Phenotypes of Reaction to Blast:

A Case Study..................................................................................................76

  • 5.4 Molecular Plant-Pathogen Interaction...........................................................81
  • 5.5 Transcriptomic Approach...............................................................................85
  • 5.6 Future Prospects.............................................................................................96

Acknowledgements..................................................................................................96

References................................................................................................................96

Introduction

The first world report of wheat blast occurrence in field conditions was in northern Parana, Brazil, in the mid-1980s (Igarashi et al., 1986). In subsequent years, the pathogen spread to new areas, and its presence has been registered in the Distrito Federal (Anjos et al., 1996) and in the states of Mato Grosso do Sul (Goulart et al., 1990), Rio Grande do Sul (Picinini & Fernandes, 1990), Sao Paulo (Igarashi, 1991),

Goiás (Prabhu et al., 1992) and Minas Gerais. Blast prevails in all the wheat-producing regions of Brazil due to the favourable conditions of high temperatures (above 20°C) and humidity (over 10 hours of leaf wetting) (Cardoso et al., 2008).

In addition to Brazil, the disease was observed on the Brazil/Paraguay border in 1987, and reached epidemic proportions in Paraguay in 2002 (Viedma & Paiva, 2002). In the lowlands of Santa Cruz, Bolivia, severe blast infections were observed in 1996, causing approximately 80% yield losses (Barea & Toledo, 1996). Subsequently it was first identified in Argentina in 2007, limited to the north of the country (Cabrera & Gutiérrez, 2007). In Uruguay, infections have been sporadic especially during the wet and warm years (Kohli et al., 2011). In 2011, wheat blast was also found in North America. A single spike of wheat with blast symptoms was observed in Princeton, Kentucky (Farman et al., 2017). In February 2016, blast was recorded in southern Bangladesh in Asia, reaching approximately 15% of the area cultivated with wheat (Malaker et al., 2016).

Blast disease or brusone is caused by the ascomycete M. oryzae B.C. Couch and L.M. Kohn (synonym Pyricularia oryzae Cavara) which infects more than 100 species of the Poaceae family including rice, wheat and barley (Choi et al., 2013). M. oryzae can infect all the aerial parts of the wheat plant, including the leaves, stems and spikes. Spike infection is the most destructive form of the disease (Prestes et al., 2007). The damage caused by blast to wheat grain production depends on the time of spike infection and the site of penetration of the fungus; it can affect the spike partially or completely.

The importance of blast disease arises from the reductions in yield and grain quality. In early infections, newly formed wheat grains are deformed, small and with low specific weight. Most of them are eliminated in the harvesting and processing. In the state of Mato Grosso do Sul, research carried out from 1988 to 1992, under natural conditions of infection in the field, showed a reduction of 10%—53% in grain yield and 14.5%-74% in the weight of the grains produced (Goulart et al., 2007). Diseased spikes have characteristic discolouration or bleaching, and the rachises exhibit a necrosis at the site of penetration of the fungus. Spikes bleaching symptoms are so impressive that damages due to blast disease could be overestimated (Goulart et al., 2007).

 
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