Emergence of wheat blast in Bangladesh was caused by a South American lineage of Magnaporthe oryzae

Abstract

BackgroundIn February 2016, a new fungal disease was spotted in wheat fields across eight districts in Bangladesh. The epidemic spread to an estimated 15,000 hectares, about 16 % of the cultivated wheat area in Bangladesh, with yield losses reaching up to 100 %. Within weeks of the onset of the epidemic, we performed transcriptome sequencing of symptomatic leaf samples collected directly from Bangladeshi fields.ResultsReinoculation of seedlings with strains isolated from infected wheat grains showed wheat blast symptoms on leaves of wheat but not rice. Our phylogenomic and population genomic analyses revealed that the wheat blast outbreak in Bangladesh was most likely caused by a wheat-infecting South American lineage of the blast fungus Magnaporthe oryzae.ConclusionOur findings suggest that genomic surveillance can be rapidly applied to monitor plant disease outbreaks and provide valuable information regarding the identity and origin of the infectious agent.Electronic supplementary materialThe online version of this article (doi:10.1186/s12915-016-0309-7) contains supplementary material, which is available to authorized users.

Wheat Blast- A New Challenge to Wheat Cultivation in South Asia

“…In case of late infection on spike, few light weight, and thin grains with black discolouration are produced. The upper portion from point of infection is always dried out and mostly remains sterile (Igarashi, 1990;Islam et al, 2016;Malaker et al, 2016;Urashima, 2010).…”

Gene Flow between Divergent Cereal- and Grass-Specific Lineages of the Rice Blast Fungus Magnaporthe oryzae

“…More recently, comparative genomics of eight isolates infecting wheat, goosegrass, rice, foxtail millet, finger millet, and barley revealed deep subdivision of M. oryzae into three groups infecting finger millet or wheat, foxtail millet, and rice or barley (13,14). Subsequent analysis of genomic data from nine wheat-infecting isolates, two ryegrassinfecting isolates, and one weeping-lovegrass-infecting isolate subdivided lineages infecting only wheat on the one hand and wheat or ryegrass on the other hand and revealed an additional lineage associated with the weeping lovegrass strain (15). Together, these studies suggest a history of host range expansion or host shifts and limited gene flow between lineages within M. oryzae.…”

A nuclear contortionist: the mitotic migration ofMagnaporthe oryzaenuclei during plant infection

“…In fact, each year M. oryzae causes an estimated $66 billion in economic damage to rice crops, destroying enough food to have fed 60 million people (Pennisi 2010). In the field, M. oryzae is developing increased resistance to commonly used fungicides (Ribas e Ribas et al 2016) and, recently, wheat blast emerged in Bangladesh (Islam et al 2016; Malaker et al 2016). Understanding cellular processes unique to M. oryzae is an important first step in the development of novel and effective methods to control the deadly plant pathogen and ensure global food security.…”