The major plant sphingolipid long chain base phytosphingosine inhibits growth of bacterial and fungal plant pathogens

Abstract

Sphingolipid long chain bases (LCBs) are building blocks of sphingolipids and can serve as signalling molecules, but also have antimicrobial activity and were effective in reducing growth of a range of human pathogens. In plants, LCBs are linked to cell death processes and the regulation of defence reactions against pathogens, but their role in directly influencing growth of plant-interacting microorganisms has received little attention. Therefore, we tested the major plant LCB phytosphingosine in in vitro tests with the plant pathogenic fungi Verticillium longisporum, Fusarium graminearum and Sclerotinia sclerotiorum, the plant symbiotic fungal endophyte Serendipita indica, the bacterial pathogens Pseudomonas syringae pv. tomato (Pst), Agrobacterium tumefaciens, and the related beneficial strain Rhizobium radiobacter. Phytosphingosine inhibited growth of these organisms at micromolar concentrations. Among the fungal pathogens, S. sclerotiorum was the most, and F. graminearum was the least sensitive. 15.9 μg/mL phytosphingosine effectively killed 95% of the three bacterial species. Plant disease symptoms and growth of Pst were also inhibited by phytosphingosine when co-infiltrated into Arabidopsis leaves, with no visible negative effect on host tissue. Taken together, we demonstrate that the plant LCB phytosphingosine inhibits growth of plant-interacting microorganisms. We discuss the potential of elevated LCB levels to enhance plant pathogen resistance.

Antifungal Peptide P852 Controls Fusarium Wilt in Faba Bean (Viciafaba L.) by Promoting Antioxidant Defense and Isoquinoline Alkaloid, Betaine, and Arginine Biosyntheses

“…In the control group, the relative contents of phytosphingosine, carnitine, and arachidonic acid were significantly increased ( Figure 7 E). This is consistent with the notion that plants produce these defense-related compounds upon biotic stress [ 76 , 77 , 78 ]. This finding may be explained by the fact that antifungal peptides can have an immediate effect on plant pathogens, while the CK group relies more on the antifungal substances produced by itself.…”

Dual action of sphinganine in the plant disease resistance to bacteria

“…We and others previously demonstrated that the co-infiltration of Pst AvrRpm1 and d18:0 or t18:0, respectively, does not induce an HR in contrast to what happens with an infiltration of an avirulent bacteria or LCB alone (Magnin-Robert et al ., 2015; Glenz et al ., 2022). Therefore, Pst expressing effectors other than AvrRpm1 were selected to elucidate whether the absence of visible HR was dependent on the effector.…”

“…In vitro tests showed that this LCB does not have an antibacterial effect on Pst AvrRpm1 , Pst AvrB and Pst AvrPphB , similarly to results obtained with P. aeruginosa (Fischer et al ., 2012). t18:0 has been shown to inhibit Pst growth (Glenz et al ., 2022). However, the authors used a smaller bacterial concentration and LB medium to perform their tests.…”

The effect of C/N ratio and its frequent addition on commensal and pathogenic bacterial abundances in shrimp Litopeaneus vanname gut in a biofloc system: Ratio and frequent addition interaction matters

“…Sphingolipid occur in cellular membranes of all eukaryotes, but only a few bacterial genera have it in their cell membrane [ 86 – 88 ]. Sphingolipid shows antimicrobial activity against a range of gram-positive and gram-negative pathogenic bacteria including Pseudomonas aeruginosa and Escherichia coli [ 50 ]. In our study, T9 showed the highest level of phytosphingosin and lower abundance level of Tenacibaculum.…”