Abstract Considering wheat as an important staple food crop worldwide and the great impact of blast, caused by Pyricularia oryzae, to decrease yield, this study aimed to investigate the involvement of ethylene on wheat susceptibility to blast based on its basal and induced levels in plant tissues. Plants from cultivars BRS Guamirim and BRS 220 (susceptible and partially resistant to blast, respectively) were non-sprayed or sprayed with Ethrel (0.0001 M) 24 h before inoculation with P. oryzae. Blast severity was higher on ethylene-sprayed plants regardless of the cultivar. High foliar ethylene concentration for inoculated plants from cultivars BRS Guamirim and BRS 220 was associated with an increase in leaf tissues susceptibility to blast. Ethylene was synthesized on inoculated leaves regardless of ethylene spray. Expressions of the genes 1-aminocyclopropane-1-carboxylate (ACC) synthase (ACS) 1, ACS 2, and ACC oxidase (ACO) were lower for plants from cultivar BRS 220 which showed lower blast severity. Peaks on the expressions of ACS 1 and ACS 2 genes for plants from cultivar BRS Guamirim non-sprayed with ethylene were stimulated by P. oryzae infection. PR-1 gene expression enhanced in response to ethylene spray indicating an increase in wheat resistance to blast mainly for plants from cultivar BR 220. In general, peroxidases, phenylalanine ammonia lyases and poliphenoloxidases activities were kept stable from 48 to 96 h after inoculation (hai) but seemed to be affected by both ethylene spray and fungal infection. For inoculated and ethylene-sprayed plants from cultivar BRS 220, a peak for chitinase activity occurred at 96 hai while β-1,3-glucanases activity was kept higher for inoculated plants from 48 to 96 hai. β-1,3-glucanases activity enhanced upon P. oryzae infection but was not potentiated by ethylene. The concentration of photosynthetic pigments decreased for inoculated plants from cultivar BRS Guamirim due to high blast severity. In conclusion, ethylene biosynthesis on wheat leaves was triggered by P. oryzae infection and host defense responses were activated.

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乙烯对小麦抗稻瘟病的影响

摘要 考虑到小麦是世界范围内重要的主粮作物，且稻瘟病菌引起的稻瘟病对减产的影响很大，本研究旨在基于乙烯在植物组织中的基础水平和诱导水平，研究乙烯对小麦稻瘟病易感性的影响。 . 来自栽培品种 BRS Guamirim 和 BRS 220（分别对稻瘟病易感和部分抗性）的植物在接种稻瘟病菌前 24 小时不喷洒或喷洒 Ethrel (0.0001 M)。无论栽培品种如何，喷洒乙烯的植物的爆炸严重程度更高。来自栽培品种 BRS Guamirim 和 BRS 220 的接种植物的高叶面乙烯浓度与叶组织对稻瘟病的敏感性增加有关。无论乙烯喷雾如何，乙烯都是在接种的叶子上合成的。基因 1-氨基环丙烷-1-羧酸 (ACC) 合酶 (ACS) 1、ACS 2 和 ACC 氧化酶 (ACO) 的表达对于来自品种 BRS 220 的植物来说是较低的，其显示出较低的稻瘟病严重性。来自未喷乙烯的栽培品种 BRS Guamirim 的植物的 ACS 1 和 ACS 2 基因表达的峰值受到米根霉感染的刺激。PR-1 基因表达响应乙烯喷雾而增强，表明小麦对稻瘟病的抗性增加，主要来自栽培品种 BR 220 的植物。总的来说，过氧化物酶、苯丙氨酸解氨酶和多酚氧化酶活性在接种后 48 至 96 小时保持稳定（海) 但似乎同时受到乙烯喷雾和真菌感染的影响。对于来自栽培品种 BRS 220 的接种和乙烯喷雾植物，几丁质酶活性的峰值出现在 96 海，而 β-1、从 48 到 96 海，接种植物的 3-葡聚糖酶活性保持较高。β-1,3-葡聚糖酶活性在米曲霉感染后增强，但不受乙烯增强。由于高瘟疫严重性，来自栽培品种 BRS Guamirim 的接种植物的光合色素浓度降低。总之，小麦叶片上的乙烯生物合成是由稻瘟病菌感染触发的，宿主防御反应被激活。