Long- and short-chain plant-produced bacterial N-acyl-homoserine lactones become components of phyllosphere, rhizosphere, and soil

• Published in: Molecular plant-microbe interactions Vol. 19; no. 3; pp. 227 - 239
• Main Authors: Scott, R.A, Weil, J, Le, P.T, Williams, P, Fray, R.G, Von Bodman, S.B, Savka, M.A
• Format: Journal Article
• Language: English
• Published: St Paul, MN APS Press 01.03.2006; The American Phytopathological Society
• Subjects: 4-Butyrolactone - analogs & derivatives; 4-Butyrolactone - chemistry; 4-Butyrolactone - metabolism; Bacterial plant pathogens; bacterial proteins; Biological and medical sciences; biosynthesis; Fundamental and applied biological sciences. Psychology; gene expression; Gram-negative bacteria; homoserine; lactones; ligases; Molecular Structure; N-acyl-homoserine lactone synthase; Nicotiana - genetics; Nicotiana - metabolism; Nicotiana tabacum; phyllosphere; Phytopathology. Animal pests. Plant and forest protection; plant exudates; Plant Leaves - genetics; Plant Leaves - metabolism; Plant Roots - genetics; Plant Roots - metabolism; Plants, Genetically Modified; Pseudomonas aeruginosa; Pseudomonas aeruginosa - genetics; Pseudomonas aeruginosa - metabolism; quorum sensing; rhizosphere; Soil - analysis; soil bacteria; tobacco; transgenes; transgenic plants; Yersinia enterocolitica; Yersinia enterocolitica - genetics; Yersinia enterocolitica - metabolism; Pseudomonadales; Stimulant plant; Plastid; Synthase; Nicotiana tabacum; Yersinia enterocolitica; Gene; Dicotyledones; Angiospermae; Phyllosphere; Pseudomonadaceae; Bacteria; Pseudomonas aeruginosa; Transgenic plant; Quorum sensing; Solanaceae; Microbial community; Enterobacteriaceae; Root; Enzyme; Plant leaf; Thin layer chromatography; Rhizosphere; Soils; Spermatophyta
• ISSN: 0894-0282; 1943-7706
• DOI: 10.1094/MPMI-19-0227

Two N-acyl-homoserine lactone (acyl-HSL) synthase genes, lasI from Pseudomonas aeruginosa and yenI from Yersinia enterocolitica, were introduced into tobacco, individually and in combination. Liquid chromatograph-tandem mass spectrometry and thin-layer chromatography confirmed products of lasI and yenI activity in single and cotransformants. Cotransformants expressing plastid-localized LasI and YenI synthases produced the major acyl-HSLs for each synthase in all tissues tested. Total acyl-HSL signals accumulated in leaf tissue up to 3 pmol/mg of fresh weight, half as much in stem tissue, and approximately 10-fold less in root tissues. Acyl-HSLs were present in aqueous leaf washes from greenhouse-grown transgenic plants. Transgenic lines grown for 14 days under axenic conditions produced detectable levels of acyl-HSLs in root exudates. Ethyl acetate extractions of rhizosphere and nonrhizosphere soil from transgenically grown plants contained active acyl-HSLs, whereas plantfree soil or rhizosphere and nonrhizosphere soil from wild-type plants lacked detectable amounts of acyl-HSLs. This work shows that bioactive acyl-HSLs are exuded from leaves and roots and accumulate in the phytosphere of plants engineered to produce acyl-HSLs. These data further suggest that plants that are bioengineered to synthesize acyl-HSLs can foster beneficial plant-bacteria communications or deter deleterious interactions. Therefore, it is feasible to use bioengineered plants to supplement soils with specific acyl-HSLs to modulate bacterial phenotypes and plant-associated bacterial community structures.