Phytotoxic properties of Pseudomonas syringae pv. syringae toxins

Iacobellis, Nicola Sante; Lavermicocca, Paola; Grgurina, Ingeborg; Simmaco, Maurizio; Ballio, A.

doi:10.1016/0885-5765(92)90038-w

Cited by 106 publications

(66 citation statements)

References 16 publications

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“…(22). Compared to the smaller cyclic lipodepsinonapeptides (such as syringomycin), the SPs generally display low levels of fungicidal activity (20). However, SP25 shows significant growth-inhibitory activity against Botrytis cinera (22).…”

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Novel Cyclic Lipodepsipeptide from Pseudomonas syringae pv. lachrymans Strain 508 and Syringopeptin Antimicrobial Activities

Grgurina

Bensaci

Pocsfalvi

et al. 2005

Antimicrob Agents Chemother

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The syringopeptins are a group of antimicrobial cyclic lipodepsipeptides produced by several plant-associated pseudomonads. A novel syringopeptin, SP508, was shown to be produced as two homologs (A and B) by Pseudomonas syringae pv. lachrymans strain 508 from apple and to structurally resemble syringopeptin SP22. SP508 differed from SP22 and other syringopeptins by having three instead of four ␣,␤-unsaturated amino acids and a longer ␤-hydroxy acyl chain. Both SP508 and SP22 displayed growth-inhibitory activities against Mycobacterium smegmatis, other gram-positive bacteria, and yeasts but not against gram-negative bacteria. Structure-activity analyses of the SP508 and SP22 homologs indicated chemical structural features that lead to enhanced antimycobacterial activity by these pseudomonad cyclic lipodepsipeptides.Syringopeptins (SPs) are bacterial secondary metabolites belonging to a class of cyclic lipodepsipeptides produced by certain pathovars of the plant bacterium Pseudomonas syringae (1,2,25,36). Their peptide portions contain either 22 (SP22) or 25 (SP25) amino acids that are predominantly hydrophobic, valine and alanine in particular. About 70% of the chiral residues are of the D configuration, and there are four ␣,␤-unsaturated and two 2,4-diaminobutyric acid residues (2,17,21,30). An N-terminal residue dehydroaminobutyric acid (Dhb) is N acylated by a 3-hydroxylated fatty acid chain containing either 10 or 12 carbon atoms; these two types of chains are designated A and B homologs and are typically the more abundant and less abundant forms, respectively. The C-terminal carboxyl group is esterified by the hydroxyl group of the allo-Thr residue positioned at the distance of 7 residues, thus forming an eightmembered lactone macrocycle. So far, two SP25 and three SP22 forms have been identified. SP25 is produced by P. syringae pv. syringae strains that have been isolated from infected millet (B359), citrus (B427) (2), and wheat (M1) (1) as well as from the wheat pathogen P. syringae pv. atrofaciens (36). An isoform differing in the C-terminal residue, SP25-Phe, was detected in a laurel-infecting strain (30). SP22 is produced by a P. syringae pv. syringae strain isolated from pear (B301) (2), and variants are produced by P. syringae pv. syringae strains from sugar cane (SP[SC]) (21) and bean (SPPhv) (17). Each SP-producing P. syringae strain produces one type of SP together with a smaller, nine-amino-acid-containing cyclic lipodepsipeptide-either syringomycin (13, 32), syringotoxin (3), syringostatin (13), or pseudomycin (5).The SPs are produced in infected plant tissues (12, 15), and they play roles as virulence factors in plant diseases (31). The phytotoxic physiological effects of the SPs were demonstrated with isolated plant mitochondria (10) and tobacco protoplasts (18). Lipid bilayer studies have revealed that the probable mechanism of action involves insertion into target membranes with formation of ion channels and consequent ion imbalances that lead to cell death (9, 18). In addition to their phyto...

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confidence: 99%

Novel Cyclic Lipodepsipeptide from Pseudomonas syringae pv. lachrymans Strain 508 and Syringopeptin Antimicrobial Activities

Grgurina

Bensaci

Pocsfalvi

et al. 2005

Antimicrob Agents Chemother

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“…All possess a characteristic tetrapeptidyl sequence (dehydroaminobutanoic acid-hydroxyaspartic acid-chlorothreonine-serine) and a ␤-hydroxy fatty acid attached to the N-terminal serine. These metabolites are fungicidal to a broad range of fungi, including yeast and human pathogens (33), and they show relatively low levels of toxicity to plants (21) and cutaneous animal tissues (33). Syringomycin E was recently shown to be partly responsible for the biological control of fungal pathogens on postharvest citrus fruits by certain P. syringae pv.…”

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Syringomycin E Inhibition of Saccharomyces cerevisiae : Requirement for Biosynthesis of Sphingolipids with Very-Long-Chain Fatty Acids and Mannose- and Phosphoinositol-Containing Head Groups

Stock

Hama

Radding

et al. 2000

Antimicrob Agents Chemother

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Syringomycin E is an antifungal cyclic lipodepsinonapeptide that inhibits the growth of Saccharomyces cerevisiae by interaction with the plasma membrane. A screen conducted to find the yeast genes necessary for its fungicidal action identified two novel syringomycin E response genes, SYR3 and SYR4. A syr3 mutant allele was complemented by ELO2 and ELO3. These genes encode enzymes that catalyze the elongation of sphingolipid very long chain fatty acids. Tetrad analysis showed that SYR3 was ELO2. Strains with deletions of SYR3/ELO2 and ELO3 were resistant to syringomycin E, and lipid analyses of both mutants revealed shortened fatty acid chains and lower levels of sphingolipids. SYR4 was identified by Tn5 inactivation of genomic library plasmids that complemented a syr4 mutant allele. SYR4 was found to be identical to IPT1, which encodes the terminal sphingolipid biosynthetic enzyme, mannosyl-diinositolphosphoryl-ceramide synthase. Deletion ⌬syr4/ ipt1 strains were viable, were resistant to syringomycin E, did not produce mannosyl-diinositolphosphorylceramide, and accumulated mannosyl-inositolphosphoryl-ceramide. Accumulation of mannosyl-inositolphosphoryl-ceramide was not responsible for resistance since a temperature-sensitive secretory pathway mutant (sec14-3 ts ) accumulated this sphingolipid and was sensitive to syringomycin E. Finally, ⌬csg1/sur1 and ⌬csg2 strains defective in the transfer of mannose to inositolphosphoryl-ceramide were resistant to syringomycin E. These findings show that syringomycin E growth inhibition of yeast is promoted by the production of sphingolipids with fully elongated fatty acid chains and the mannosyl and terminal phosphorylinositol moieties of the polar head group.Syringomycin E is a member of a family of small cyclic lipodepsinonapeptides (ca. 1,200 Da) produced by the plant bacterium Pseudomonas syringae pv. syringae (38). Other members include syringomycin A 1 and G, the syringostatins, the syringotoxins, and the pseudomycins (2, 38). All possess a characteristic tetrapeptidyl sequence (dehydroaminobutanoic acid-hydroxyaspartic acid-chlorothreonine-serine) and a ␤-hydroxy fatty acid attached to the N-terminal serine. These metabolites are fungicidal to a broad range of fungi, including yeast and human pathogens (33), and they show relatively low levels of toxicity to plants (21) and cutaneous animal tissues (33). Syringomycin E was recently shown to be partly responsible for the biological control of fungal pathogens on postharvest citrus fruits by certain P. syringae pv. syringae strains (5). Syringomycin E interacts with the fungal plasma membrane, where it causes K ϩ efflux, Ca 2ϩ influx, and changes in membrane potential by processes that are likely related to channel formation (14, 38).Molecular genetic studies with yeast were initiated to more precisely define the antifungal mechanism of action of syringomycin E. Syringomycin E-resistant mutants of Saccharomyces cerevisiae were generated to permit identification of the mutated genes by complementation (39). Two genes, ...

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“…4 ) The syringopeptins are more phytotoxic than the three shorter phytotoxins and may act synergistically with the latter three. 5) From our research of phytotoxins produced by a strain of P. syringae pv. syringae isolated from sugar cane (SCI), we have reported that this bacterial isolate produced syringomycin.…”

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confidence: 99%