Metabolomic evaluation of PGPR defence priming in wheat (Triticum aestivum L.) cultivars infected with Puccinia striiformis f. sp. tritici (stripe rust)

Manamele D Mashabela; Fidele Tugizimana; Paul A Steenkamp; Lizelle A Piater; Ian A Dubery; Tarekegn Terefe; Msizi I Mhlongo

doi:10.3389/fpls.2023.1103413

Metabolomic evaluation of PGPR defence priming in wheat (Triticum aestivum L.) cultivars infected with Puccinia striiformis f. sp. tritici (stripe rust)

Front Plant Sci. 2023 Apr 12:14:1103413. doi: 10.3389/fpls.2023.1103413. eCollection 2023.

Authors

Manamele D Mashabela¹, Fidele Tugizimana^{1

2}, Paul A Steenkamp¹, Lizelle A Piater¹, Ian A Dubery¹, Tarekegn Terefe³, Msizi I Mhlongo¹

Affiliations

¹ Research Centre for Plant Metabolomics, Department of Biochemistry, University of Johannesburg, Johannesburg, South Africa.
² International Research and Development Division, Omnia Group, Ltd., Johannesburg, South Africa.
³ Division of Small Grain Diseases and Crop Protection, Agricultural Research Council-Small Grains Institute (ARC-SGI), Private Bag X29 Bethlehem, Free State, Bethlehem, South Africa.

Abstract

Plant-microbe interactions are a phenomenal display of symbiotic/parasitic relationships between living organisms. Plant growth-promoting rhizobacteria (PGPR) are some of the most widely investigated plant-beneficial microbes due to their capabilities in stimulating plant growth and development and conferring protection to plants against biotic and abiotic stresses. As such, PGPR-mediated plant priming/induced systemic resistance (ISR) has become a hot topic among researchers, particularly with prospects of applications in sustainable agriculture. The current study applies untargeted ultra-high performance liquid chromatography-high-definition mass spectrometry (UHPLC-HDMS) to investigate PGPR-based metabolic reconfigurations in the metabolome of primed wheat plants against Puccinia striiformis f. sp. tricti (Pst). A seed bio-priming approach was adopted, where seeds were coated with two PGPR strains namely Bacillus subtilis and Paenibacillus alvei (T22) and grown under controlled conditions in a glasshouse. The plants were infected with Pst one-week post-germination, followed by weekly harvesting of leaf material. Subsequent metabolite extraction was carried out for analysis on a UHPLC-HDMS system for data acquisition. The data was chemometrically processed to reveal the underlying trends and data structures as well as potential signatory biomarkers for priming against Pst. Results showed notable metabolic reprogramming in primary and secondary metabolism, where the amino acid and organic acid content of primed-control, primed-challenged and non-primed-challenged plants were differentially reprogrammed. Similar trends were observed from the secondary metabolism, in which primed plants (particularly primed-challenged) showed an up-regulation of phenolic compounds (flavonoids, hydroxycinnamic acids-HCAs- and HCA amides) compared to the non-primed plants. The metabolomics-based semi-quantitative and qualitative assessment of the plant metabolomes revealed a time-dependent metabolic reprogramming in primed-challenged and primed-unchallenged plants, indicating the metabolic adaptations of the plants to stripe rust infection over time.

Keywords: Puccinia striiformis f. sp. tricti; induced systematic resistance; metabolic reprogramming; plant growth promoting rhizobacteria; plant priming; ultra-high performance liquid chromatography-high-definition mass spectrometry.

Grants and funding

Funding from the South African National Research Foundation to MIM (grant number 129775) supported the research. The funder had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.