Tente Eleni, Carrera Esther, Gordon Anna, Boyd Lesley A
National Institute of Agricultural Botany, Cambridge CB3 0LE, United Kingdom.
Instituto de Biología Molecular y Celular de Plantas, Consejo Superior de Investigaciones Cientificas, Universidad Politécnica de Valencia, Valencia 46022, Spain.
Phytopathology. 2022 Apr;112(4):842-851. doi: 10.1094/PHYTO-05-21-0189-R. Epub 2022 Mar 17.
Partial resistance to the biotrophic fungal pathogen , causal agent of ergot, has been found that colocates with mutant alleles of the wheat () loci on chromosomes 4B and 4D. These loci represent the wheat orthologs of the Della genes. To investigate the role of the mutant DELLA proteins in ergot resistance, we assessed . infection in wheat near-isogenic lines (NILs) carrying the gibberellic acid (GA)-insensitive semidwarf alleles - and - and the severe dwarf alleles - and -. NILs of the GA-sensitive alleles (chromosome 2D) and (chromosome 5A) were also included. A general trend toward increased resistance to . , with smaller and lighter sclerotia, was observed on the NILs -, -, -, and -, and also on . Levels of the bioactive GA and the auxin indole-3-acetic acid increased after inoculation with . , following similar patterns and implicating a potential auxin-mediated induction of GA biosynthesis. In contrast, jasmonic acid (JA) levels fell in the parental lines 'Mercia' and 'Maris Huntsman' after inoculation with . , but increased in all the -mutant NILs. Inoculation with . did not show any informative changes in the levels of salicylic acid. Our results suggest that GA-mediated degradation of the DELLA proteins and down-regulation of JA-signaling pathways supports infection of wheat by . . As these responses are generally associated with necrotrophic fungal pathogens, we propose that the biotroph . may have a necrotrophic growth stage.
已发现对麦角生物营养型真菌病原体（麦角病因）的部分抗性与4B和4D染色体上小麦（）基因座的突变等位基因共定位。这些基因座代表了小麦中与拟南芥Della基因直系同源的基因。为了研究突变的DELLA蛋白在麦角抗性中的作用，我们评估了携带赤霉素（GA）不敏感半矮化等位基因 - 和 - 以及严重矮化等位基因 - 和 - 的小麦近等基因系（NILs）中的感染情况。还包括了GA敏感等位基因（2D染色体）和（5A染色体）的NILs。在NILs -、 -、 - 和 - 以及上观察到对麦角菌抗性增加的总体趋势，菌核更小、更轻。接种麦角菌后，生物活性GA和生长素吲哚 - 3 - 乙酸的水平升高，遵循相似模式，暗示生长素可能介导GA生物合成的诱导。相比之下，接种麦角菌后，亲本系“Mercia”和“Maris Huntsman”中的茉莉酸（JA）水平下降，但在所有 - 突变NILs中升高。接种麦角菌后，水杨酸水平未显示任何有意义的变化。我们的结果表明，GA介导的DELLA蛋白降解和JA信号通路的下调支持麦角菌对小麦的感染。由于这些反应通常与坏死营养型真菌病原体相关，我们提出生物营养型麦角菌可能有一个坏死营养型生长阶段。
