Ding Yi, Gardiner Donald M, Kazan Kemal
The Plant Breeding Institute, School of Life & Environmental Sciences, Faculty of Science, The University of Sydney, Cobbitty, 2570, New South Wales, Australia; Agriculture and Food, Commonwealth Scientific and Industrial Research Organization, 306 Carmody Road, St Lucia, 4067, Queensland, Australia.
Queensland Alliance for Agriculture and Food Innovation (QAAFI), The University of Queensland, Brisbane, St Lucia, 4067, Queensland, Australia; Agriculture and Food, Commonwealth Scientific and Industrial Research Organization, 306 Carmody Road, St Lucia, 4067, Queensland, Australia.
Microbiol Res. 2022 Mar;256:126951. doi: 10.1016/j.micres.2021.126951. Epub 2021 Dec 17.
The fungal pathogen Fusarium graminearum (Fg) infects both heads and roots of cereal crops causing several economically important diseases such as head blight, seedling blight, crown rot and root rot. Trichothecene mycotoxins such as deoxynivalenol (DON), a well-known virulence factor, produced by Fg during disease development is also an important health concern. Although how Fg infects above-ground tissues is relatively well studied, very little is known about molecular processes employed by the pathogen during below-ground infection. Also unknown is the role of DON during root infection. In the present study, we analyzed the transcriptome of Fg during root infection of the model cereal Brachypodium distachyon (Bd). We also compared our Fg transcriptome data obtained during Bd root infection with those reported during wheat head infection. These analyses suggested that both shared and unique infection strategies were employed by the pathogen during colonization of different host tissues. Several metabolite biosynthesis genes induced in Fg during root infection could be linked to phytohormone production, implying that the pathogen likely interferes with root specific defenses. In addition, to understand the role of DON in Fg root infection, we analyzed the transcriptome of the DON deficient Tri5 mutant. These analyses showed that the absence of DON had a significant effect on fungal transcriptional responses. Although DON was produced in infected roots, this mycotoxin did not act as a Fg virulence factor during root infection. Our results reveal new mechanistic insights into the below-ground strategies employed by Fg that may benefit the development of new genetic tools to combat this important cereal pathogen.
真菌病原体禾谷镰刀菌（Fg）可感染谷类作物的穗部和根部，引发几种具有重要经济影响的病害，如赤霉病、苗枯病、冠腐病和根腐病。在病害发展过程中，Fg产生的诸如脱氧雪腐镰刀菌烯醇（DON）等单端孢霉烯族霉菌毒素是一种广为人知的毒力因子，也是一个重要的健康问题。尽管Fg如何感染地上组织已得到相对充分的研究，但对于该病原体在地下感染过程中所采用的分子机制却知之甚少。此外，DON在根部感染中的作用也尚不明确。在本研究中，我们分析了Fg在模式谷类植物短柄草（Bd）根部感染过程中的转录组。我们还将在Bd根部感染过程中获得的Fg转录组数据与小麦穗部感染过程中报告的数据进行了比较。这些分析表明，在定殖于不同宿主组织的过程中，病原体采用了共同的和独特的感染策略。在根部感染过程中Fg中诱导的几个代谢物生物合成基因可能与植物激素的产生有关，这意味着病原体可能干扰根部特异性防御。此外，为了了解DON在Fg根部感染中的作用我们分析了DON缺陷型Tri5突变体的转录组。这些分析表明，DON的缺失对真菌的转录反应有显著影响。尽管在受感染的根部产生了DON，但这种霉菌毒素在根部感染过程中并不是Fg的毒力因子。我们的研究结果揭示了Fg在地下采用的新机制，这可能有助于开发新的遗传工具来对抗这种重要的谷类病原体。
