Wheat blast research: Status and imperatives

Sharma, Rajiv

doi:10.5897/ajar2016.11860

Cited by 10 publications

(2 citation statements)

References 32 publications

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“…This is evident based on the increase in the yearly number of original articles and reviews published after the major epidemics reported in the Cerrado, Brazil, and disease's introduction into both Asia and Africa (Figure 2A). (Rajiv 2017;Sadat and Choi 2017;Cruz and Valent 2017;Mottaleb et al 2018Mottaleb et al , 2019Ceresini et al 2018Ceresini et al , 2019Islam et al , 2020Kamoun et al 2019;Tembo 2019;Yesmin et al 2020;Mbinda and Masaki 2021, Singh et al 2021, Tosa 2021. While some aspects have been given more attention, such as the taxonomy and population genetics (Couch and Kohn 2002;Tanaka et al 2009;Luo and Zhang 2013;Maciel et al 2014;Murata et al 2014;Klaubauf et al 2014;Gladieux et al 2015Gladieux et al , 2018Castroagudín et al 2016;Valent et al 2019), chemical control (Kim et al 2003;Cruz et al 2011Cruz et al , 2019Pagani et al 2014;Rocha et al 2014;Castroagudín et al 2015;Oliveira et al 2015;Dorigan et al 2019;D'Ávila et al 2021;Ascari et al 2021) and host genetic resistance (Cruz et al 2016b;Anh et al 2018;Rocha et al 2019;…”

Section: Economical and Scientific Importancementioning

confidence: 99%

Taxonomic and pathogenic diversity of the blast pathogen populations infecting wheat and grasses in Minas Gerais

Ascari¹,

Ponte²

2021

Preprint

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The blast disease of Poaceae is caused by a large species complex, among which P. oryzae is composed of several host-specialized lineages. The Pyricularia oryzae Triticum pathotype (PoT) causes the blast disease in wheat, but is also capable of infecting other grasses, which may serve as an inoculum reservoir for epidemics in wheat. In Brazil, severe wheat blast epidemics are most common in the Cerrado region. The dominant hypothesis is that signal grass (Urochloa sp.) and other gramineous plants harbor the wheat blast pathogen, thus serving as a major reservoir of inoculum for epidemics in wheat. A two-year survey of the Pyricularia blast pathogens was conducted in both wheat and non-wheat areas as well as prior (February) and during (May) the wheat growing season in Minas Gerais. A total of 1,368 plant samples representative of 31 Poaceae species, including wheat, were collected and inspected for the presence of blast symptoms. During the isolations, 932 isolates were obtained, being one fourth obtained from gramineous plants. A subset of 572 isolates was selected for identification at the species level based on portions of the CH7-BAC9 gene sequences. Most of the isolates (n = 494) were P. oryzae, within which 68% were PoT and 32% non-PoT based on two PCR assays targeting (MoT3 and C17 PCR assays). The PoT lineage was found predominantly (97%) in wheat and rarely in the other hosts, even nearby wheat fields (2.1%), as well as at longer distances from wheat regions (0.1%). The blast pathogen population isolated from signal grass grouped in different clades from PoT, and therefore referred to Urochloa lineage (PoU). A series of cross-inoculation greenhouse experiments was conducted using wheat (cv. BRS Guamirim and BR 18-Terena) and signal grass (cv. Marandu) as host and 14 PoT and six PoU isolates as pathogen factor. In the first leaf-inoculation experiment, results showed a significant interaction between host and pathogen; PoT was strongly/weakly aggressive towards wheat/signal grass and PoU was strongly/weakly aggressive towards signal grass/wheat. In inoculated wheat heads, PoT was more aggressive (>91% infected spikelets) than PoU (52% infected spikelets). In a third experiment, four signal grass cultivars (Marandu, Basilisk, Piatã, and Xaraés) were inoculated with the same set of 20 isolates. Similarly, signal grass cultivars were generally more susceptible to PoU than PoT. Severity induced by PoU was twice (7.7% severity) as high as PoT (3.8%) and so was the number of conidia/leaf produced by PoU (47,500) and PoT (23,200). Two groups of signal grass cultivars were formed, the most susceptible composed of Marandu and Basilisk and the least susceptible composed of Piatã and Xaraés. Results of our study confirm the host-specialization and the shaping of the blast populations according to the host. We further suggest that grasses in general, especially signal grass, may not play a major role as an inoculum reservoir for PoT, as it harbors mainly the PoU population. However, due to the large extent of pasture-growing regions and cross-infection ability in wheat, signal grass may harbor amounts of PoT inoculum that are sufficient for initiating leaf and head blast epidemics in wheat blast in Minas Gerais state.

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Section: Economical and Scientific Importancementioning

confidence: 99%

Taxonomic and pathogenic diversity of the blast pathogen populations infecting wheat and grasses in Minas Gerais

Ascari¹,

Ponte²

2021

Preprint

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“…Adapted from [65]. began to develop short, medium, and long-term strategies to limit the spread of the disease as well as turn their attention to sustaining wheat production in this region to face the lethal disease [14,68,71]. Scientists and policymakers in the region took several initiatives in collaboration with CIMMYT, ACIAR, and the USA for the development of a wheat blast resistant wheat variety.…”

Section: Wheat Blast: a New Threat To Food Securitymentioning

confidence: 99%

Mitigating the twin problems of malnutrition and wheat blast by one wheat variety, ‘BARI Gom 33’, in Bangladesh

et al. 2019

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For the first time in history outside of Latin America, deadly wheat blast caused by the fungus Magnaporthe oryzae pathotype triticum (MoT) emerged in the 2015–2016 wheat (Triticum aestivum L.) season of Bangladesh. Bangladesh, a country in South Asia, has a population of nearly 160 million, of which 24.3% are classified as poor. Consequently, malnutrition and micronutrient deficiency are highly prevalent, particularly among school going children and lactating women. Bangladesh Wheat and Maize Research Institute (BWMRI), with the technical support of the International Maize and Wheat Improvement Center (CIMMYT), Mexico, has developed and released a new wheat ‘BARI Gom 33’. The new wheat is a zinc-enriched (Zn) biofortified wheat, resistant to the deadly wheat blast disease. ‘BARI Gom 33’ provides 5–8% more yield than the check varieties in Bangladesh. Rapid dissemination of it in Bangladesh, therefore, can not only combat wheat blast but also mitigate the problem of Zn deficiency and ensure income for resource-poor wheat farmers. Importantly, a large portion of the current wheat area in India and Pakistan is vulnerable to wheat blast, due to the similarities of the agro-climatic conditions of Bangladesh. As wheat blast is mainly a seed-borne disease, a rapid scaling out of the new wheat in Bangladesh can reduce the probability of MoT intrusion in India and Pakistan, and thereby generate positive externalities to the food security of more than 1 billion people in South Asia. This study explains the development process of ‘BARI Gom 33’; the status of malnutrition in Bangladesh, and the possible economic gain from a rapid scaling out of ‘BARI Gom 33’ in Bangladesh. A few policies are recommended based on the discussions.

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Progress and Challenges of Wheat Production in the Era of Climate Change: A Bangladesh Perspective

Barma

Hossain

Hakim

et al. 2019

Wheat Production in Changing Environments

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Wheat blast research: Status and imperatives

Cited by 10 publications

References 32 publications

Taxonomic and pathogenic diversity of the blast pathogen populations infecting wheat and grasses in Minas Gerais

Taxonomic and pathogenic diversity of the blast pathogen populations infecting wheat and grasses in Minas Gerais

Mitigating the twin problems of malnutrition and wheat blast by one wheat variety, ‘BARI Gom 33’, in Bangladesh

Progress and Challenges of Wheat Production in the Era of Climate Change: A Bangladesh Perspective

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