ABSTRACT

Fusarium graminearum is a devastating pathogen of small grain cereals causing both Fusarium head blight (FHB) and Fusarium root rot (FRR). Exogenous application of phytohormones has been shown to affect FHB resistance. In contrast to FHB, FRR remains poorly characterised and it is unknown whether phytohormones play similar roles in FHB and FRR. In this present study, B. distachyon floral tissues at mid-anthesis and root tissues from seedlings were exogenously treated with several phytohormones before inoculation with F. graminearum. The canonical defence-associated phytohormones had differing effects on FHB and FRR. Salicylic acid (SA) significantly increased susceptibility to FRR but not to FHB while jasmonic acid (JA) and ethylene increased resistance to FRR but increased susceptibility to FHB. Additionally, the growth-associated phytohormones auxin and cytokinin significantly increased resistance and susceptibility, respectively, to both diseases. This study is the first to compare phytohormone effects between FHB and FRR in the same host.

Highlight

The tissue-dependent effects of defence phytohormones and tissue-independent effects of development phytohormones on F. graminearum-induced Fusarium head blight and Fusarium root rot diseases in the model cereal Brachypodium distachyon.

Abbreviations: ACC, 1-aminocyclopropane-1-carboxylic acid; BABA, 3-aminobutanoic acid; dpi, days post inoculation; FHB, Fusarium head blight; FRR, Fusarium root rot; IAA indole-3-acetic acid; JA, jasmonic acid; NAA, 1-naphthaleneacetic acid; PDA, potato dextrose agar; RNL, root necrosis length; SA, salicylic acid

摘要

禾谷镰刀菌（Fusarium graminearum）是小谷类谷物的毁灭性病原体，可引起镰刀菌枯萎病（FHB）和镰刀菌根腐病（FRR）。已证明外源施用植物激素会影响FHB耐药性。与FHB相比，FRR的特征仍然很差，尚不清楚植物激素在FHB和FRR中是否起类似的作用。在本研究中，在接种禾本科镰刀菌之前，先用几种植物激素对花药中段的B. distachyon花卉组织和幼苗的根组织进行外源处理。。防御相关的典型植物激素对FHB和FRR的影响不同。水杨酸（SA）显着增加了对FRR的敏感性，但对FHB的敏感性不明显，而茉莉酸（JA）和乙烯对FRR的抵抗力却增加了对FHB的敏感性。另外，与生长相关的植物激素生长素和细胞分裂素分别显着增加了对两种疾病的抵抗力和敏感性。这项研究是首次比较同一宿主中FHB和FRR之间的植物激素作用。

突出

防御激素和发展植物激素的组织独立影响的相关组织的影响禾谷镰刀菌诱导赤霉病和镰刀菌根腐病疾病模型中的谷物穗短柄草。

缩写：ACC，1-氨基环丙烷-1-羧酸；BABA，3-氨基丁酸; dpi，接种后天数；FHB，镰刀菌枯萎病；FRR，镰刀菌根腐病；IAA吲哚-3-乙酸；JA，茉莉酸；NAA，1-萘乙酸; PDA，马铃薯葡萄糖琼脂；RNL，根坏死长度；SA，水杨酸