Wheat transcriptome profiling reveals abscisic and gibberellic acid treatments regulate early-stage phytohormone defense signaling, cell wall fortification, and metabolic switches following Fusarium graminearum-challenge

BMC Genomics

Nora A. Foroud¹  Leann M. Buhrow²  Dustin Cram²  Michele C. Loewen³  Youlian Pan⁴  Ziying Liu⁴  Tanya Sharma⁵ 

[1] Agriculture and Agri-food Canada, Lethbridge Research and Development Centre, 5403 1st Ave, T1J 4B1, Lethbridge, AB, Canada;National Research Council of Canada, Aquatic and Crop Resources Development Research Centre, 110 Gymnasium Place, S7N 0M8, Saskatoon, SK, Canada;National Research Council of Canada, Aquatic and Crop Resources Development Research Centre, 110 Gymnasium Place, S7N 0M8, Saskatoon, SK, Canada;University of Ottawa, Department of Chemistry and Biomolecular Sciences, 150 Louis-Pasteur Pvt, K1N 6N5, Ottawa, ON, Canada;National Research Council of Canada, Aquatic and Crop Resources Development Research Centre, 100 Sussex Drive, K1A 0R6, Ottawa, ON, Canada;National Research Council of Canada, Digital Technologies Research Centre, 1200 Montreal Road, K1A 0R6, Ottawa, ON, Canada;University of Ottawa, Department of Chemistry and Biomolecular Sciences, 150 Louis-Pasteur Pvt, K1N 6N5, Ottawa, ON, Canada;

关键词: Wheat;    Triticum aestivum;    Fusarium graminearum;    Fusarium head blight;    Phytohormone;    Abscisic acid;    Gibberellic acid;    Differentially expressed genes;    RNA-seq;   

DOI  :  10.1186/s12864-021-08069-0

来源: Springer

【 摘 要 】

BackgroundTreatment of wheat with the phytohormones abscisic acid (ABA) and gibberellic acid (GA) has been shown to affect Fusarium head blight (FHB) disease severity. However, the molecular mechanisms underlying the elicited phenotypes remain unclear. Toward addressing this gap in our knowledge, global transcriptomic profiling was applied to the FHB-susceptible wheat cultivar ‘Fielder’ to map the regulatory responses effected upon treatment with ABA, an ABA receptor antagonist (AS6), or GA in the presence or absence of Fusarium graminearum (Fg) challenge.ResultsSpike treatments resulted in a total of 30,876 differentially expressed genes (DEGs) identified in ‘Fielder’ (26,004) and the Fg (4872) pathogen. Topology overlap and correlation analyses defined 9689 wheat DEGs as Fg-related across the treatments. Further enrichment analyses demonstrated that these included expression changes within ‘Fielder’ defense responses, cell structural metabolism, molecular transport, and membrane/lipid metabolism. Dysregulation of ABA and GA crosstalk arising from repression of ‘Fielder’ FUS3 was noted. As well, expression of a putative Fg ABA-biosynthetic cytochrome P450 was detected. The co-applied condition of Fg + ABA elicited further up-regulation of phytohormone biosynthesis, as well as SA and ET signaling pathways and cell wall/polyphenolic metabolism. In contrast, co-applied Fg + GA mainly suppressed phytohormone biosynthesis and signaling, while modulating primary and secondary metabolism and flowering. Unexpectedly, co-applied Fg + AS6 did not affect ABA biosynthesis or signaling, but rather elicited antagonistic responses tied to stress, phytohormone transport, and FHB disease-related genes.ConclusionsObserved exacerbation (misregulation) of classical defense mechanisms and cell wall fortifications upon ABA treatment are consistent with its ability to promote FHB severity and its proposed role as a fungal effector. In contrast, GA was found to modulate primary and secondary metabolism, suggesting a general metabolic shift underlying its reduction in FHB severity. While AS6 did not antagonize traditional ABA pathways, its impact on host defense and Fg responses imply potential for future investigation. Overall, by comparing these findings to those previously reported for four additional plant genotypes, an additive model of the wheat-Fg interaction is proposed in the context of phytohormone responses.

【 授权许可】

CC BY