Wheat blast caused by<i>Magnaporthe oryzae</i>pv.<i>Triticum</i>is efficiently controlled by the plant defence inducer isotianil

Wheat blast caused by Magnaporthe oryzae pathotype Triticum (MoT), initially restricted to South America, is a global threat for wheat after spreading to Asia in 2016 by the introduction of contaminated seeds, raising the question about transmission of the pathogen from seeds to seedlings, a process so far not well understood. We therefore studied the relationship between seed infection and disease symptoms on seedlings and adult plants. To accomplish this objective, we inoculated spikes of wheat cv. Apogee with a transgenic isolate (MoT‐DsRed, with the addition of being resistant to hygromycin). We identified MoT‐DsRed in experiments using hygromycin resistance for selection or by observation of DsRed fluorescence. The seeds from infected plants looked either apparently healthy or shrivelled. To evaluate the transmission, two experimental designs were chosen (blotter test and greenhouse) and MoT‐DsRed was recovered from both. This revealed that MoT is able to colonize wheat seedlings from infected seeds under the ground. The favourable conditions of temperature and humidity allowed a high recovery rate of MoT from wheat shoots when grown in artificial media. Around 42 days after germination of infected seeds, MoT‐DsRed could not be reisolated, indicating that fungal progression, at this time point, did not proceed systemically/endophytically. We hypothesize that spike infection might occur via spore dispersal from infected leaves rather than within the plant. Because MoT‐DsRed was not only successfully reisolated from seed coats and germinating seeds with symptoms, but also from apparently healthy seeds, urgent attention is needed to minimize the risks of inadvertent dispersal of inoculum.

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“…The infection of spikes from cv. Apogee by Argentinian MoT isolates was recently reported (Portz et al, 2020).…”

Section: Discussionmentioning

confidence: 81%

Tracing seed to seedling transmission of the wheat blast pathogenMagnaporthe oryzaepathotypeTriticum

et al. 2021

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“…Isotianil is one such elicitors which acts as a salicylic acid (SA) mimic, with proven activity against rice blast (Bektas and Eulgem, 2014) and wheat blast (Portz et al, 2020). It was discovered by Bayer in 1997 (Toquin et al, 2012).…”

Section: Introductionmentioning

confidence: 99%

Disentangling the resistant mechanism of Fusarium wilt TR4 interactions with different cultivars and its elicitor application

Zhou

He²,

Tian³

et al. 2023

Front. Plant Sci.

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Fusarium wilt of banana, especially Tropical Race 4 (TR4) is a major factor restricting banana production. Developing a resistant cultivar and inducing plant defenses by elicitor application are currently two of the best options to control this disease. Isotianil is a monocarboxylic acid amide that has been used as a fungicide to control rice blast and could potentially induce systemic acquired resistance in plants. To determine the control effect of elicitor isotianil on TR4 in different resistant cultivars, a greenhouse pot experiment was conducted and its results showed that isotianil could significantly alleviate the symptoms of TR4, provide enhanced disease control on the cultivars ‘Baxi’ and ‘Yunjiao No.1’ with control effect 50.14% and 56.14%, respectively. We compared the infection processes in ‘Baxi’ (susceptible cultivars) and ‘Yunjiao No.1’ (resistant cultivars) two cultivars inoculated with pathogen TR4. The results showed that TR4 hyphae could rapidly penetrate the cortex into the root vascular bundle for colonization, and the colonization capacity in ‘Baxi’ was significantly higher than that in ‘Yunjiao No.1’. The accumulation of a large number of starch grains was observed in corms cells, and further analysis showed that the starch content in ‘Yunjiao No. 1’ as resistant cultivar was significantly higher than that in ‘Baxi’ as susceptible cultivar, and isotianil application could significantly increase the starch content in ‘Baxi’. Besides, a mass of tyloses were observed in the roots and corms and these tyloses increased after application with isotianil. Furthermore, the total starch and tyloses contents and the control effect in the corms of ‘Yunjiao No.1’ was higher than that in the ‘Baxi’. Moreover, the expression levels of key genes for plant resistance induction and starch synthesis were analyzed, and the results suggested that these genes were significantly upregulated at different time points after the application of isotianil. These results suggest that there are significant differences between cultivars in response to TR4 invasion and plant reactions with respect to starch accumulation, tyloses formation and the expression of plant resistance induction and starch synthesis related genes. Results also indicate that isotianil application may contribute to disease control by inducing host plant defense against TR4 infection and could be potentially used together with resistant cultivar as integrated approach to manage this destructive disease. Further research under field conditions should be included in the next phases of study.

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Wheat blast caused byMagnaporthe oryzaepv.Triticumis efficiently controlled by the plant defence inducer isotianil

Cited by 2 publications

References 32 publications

Tracing seed to seedling transmission of the wheat blast pathogenMagnaporthe oryzaepathotypeTriticum

Tracing seed to seedling transmission of the wheat blast pathogenMagnaporthe oryzaepathotypeTriticum

Disentangling the resistant mechanism of Fusarium wilt TR4 interactions with different cultivars and its elicitor application

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