The plant immunity inducer pipecolic acid accumulates in the xylem sap and leaves of soybean seedlings following Fusarium virguliforme infection. (February 2016)

• Record Type: Journal Article
• Authors: Abeysekara, Nilwala S.; Swaminathan, Sivakumar; Desai, Nalini; Guo, Lining; Bhattacharyya, Madan K.
• Is Part Of: Plant science. Volume 243(2016:Feb.)
• Page Start: 105
• Page End: 114
• Publication Date: 2016-02
• Subjects: BLOB binary large object -- BSTFA bistrimethyl-silyl-triflouroacetamide -- ESI electrospray ionization -- FT-ICR Fourier transform ion cyclotron resonance -- 13-HODE 13-(S)-hydroxyoctadecadienoic acid -- 9-HODE 9-Hydroxy-10, 12-octadecadienoic acid -- LAN local area network -- LIMS laboratory information management system -- LIT linear ion-trap -- Pip pipecolic acid -- QC quality control -- SDS sudden death syndrome; Fusarium virguliforme -- Xylem sap -- Metabolites -- Soybean -- Sudden death syndrome -- Pipecolic acid; Botany -- Periodicals; Botanique -- Périodiques; 580
• DOI: 10.1016/j.plantsci.2015.11.008
• Languages: English
• ISSNs: 0168-9452

Abstract

Highlights: The immunity inducer pipecolic acid accumulates in F. virguliforme -infected soybean. GmALD1 is induced following F. virguliforme infection. ALD1 homologs are induced following pathogen infection in both eudicots and monocots. The TCA cycle is suppressed following infection of soybean with F. virguliforme . Peroxidated lipids accumulate in soybean following F. virguliforme infection. Abstract: The causal agent of the soybean sudden death syndrome (SDS), Fusarium virguliforme, remains in infected roots and secretes toxins to cause foliar SDS. In this study we investigated the xylem sap, roots, and leaves of F. virguliforme -infected and -uninfected soybean seedlings for any changes in a set of over 3, 000 metabolites following pathogen infection by conducting GC/MS and LC/MS/MS, and detected 273 biochemicals. Levels of many intermediates of the TCA cycle were reduced suggesting suppression of this metabolic pathway by the pathogen. There was an increased accumulation of peroxidated lipids in leaves of F. virguliforme -infected plants suggesting possible involvement of free radicals and lipoxygenases in foliar SDS development. Levels of both isoflavone conjugates and isoflavonoid phytoalexins were decreased in infected roots suggesting degradation of these metabolites by the pathogen to promote root necrosis. The levels of the plant immunity inducer pipecolic acid (Pip) and the plant hormone salicylic acid (SA) were significantly increased in xylem sap (in case of Pip) and leaves (in case of both Pip and SA) of F. virguliforme -infected soybean plants compared to the control plants. This suggests a major signaling role of Pip in inducing host defense responses in above ground parts of the F. virguliforme -infected soybean. Increased accumulation of pipecolic acid in foliar tissues was associated with the induction of GmALD1, the soybean homolog of Arabidopsis ALD1 . This metabolomics study generated several novel hypotheses for studying the mechanisms of SDS development in soybean.