Effect of Lipopolysaccharides from Escherichia coli and Pseudomonas aeruginosa on Embryogenic Callus from Alfalfa (Medicago sativa L.)

Ayşe Üstün Başkut U., Yazicilar B., ATICI Ö., Halis B., Geyik M. Ş.

Biology Bulletin, cilt.53, sa.2, 2026 (SCI-Expanded, Scopus) identifier identifier identifier

  • Yayın Türü: Makale / Tam Makale
  • Cilt numarası: 53 Sayı: 2
  • Basım Tarihi: 2026
  • Doi Numarası: 10.1134/s1062359025609620
  • Dergi Adı: Biology Bulletin
  • Derginin Tarandığı İndeksler: Science Citation Index Expanded (SCI-EXPANDED), Scopus, Artic & Antarctic Regions, BIOSIS, Zoological Record, Academic Search Ultimate (EBSCO), Natural Science Collection (ProQuest), Biological Science Database (ProQuest), Biomedical Reference Collection: Corporate Edition (EBSCO)
  • Anahtar Kelimeler: lipopolysaccharide, <italic>Medicago sativa</italic>, callus, polyphenol oxidase, phenolic compound, lignin, SDS-PAGE
  • Atatürk Üniversitesi Adresli: Evet

Özet

Abstract: Lipopolysaccharides (LPS), which are derived from bacterial cell walls, play a critical role in plant-microbe interactions. However, their effects on somatic embryogenesis and biochemical responses in plants are still not fully understood. This study examines the morphological, physiological, and biochemical impacts of LPS extracted from non-pathogenic Escherichia coli (ATCC 25922) and Pseudomonas aeruginosa (ATCC 27853) on embryogenic callus formation in alfalfa (Medicago sativa L.). The LPS was extracted from bacterial strains, and its effect on callus induction from alfalfa leaf explants was assessed by culturing the explants on MS medium supplemented with 1000 μg mL–1 LPS, with all changes monitored over a 30-day period. While callus yield remained high across all treatments, the LPS exposure significantly altered tissue structure, enhancing embryogenic potential. Notably, P. aeruginosa LPS had a more pronounced effect than E. coli LPS, resulting in a more compact, non-embryogenic control callus. Biochemical analyses revealed a significant reduction in sucrose and starch content in both LPS-treated groups, with a more substantial decrease in starch levels in the P. aeruginosa LPS-treated group. Both LPS treatments also increased polyphenol oxidase (PPO) activity and total phenolic content, while lignin content decreased compared to the control. The purity and structural characteristics of LPS isolated from both bacterial strains were confirmed using SDS-PAGE, UV-Vis, and FTIR spectroscopy. SDS-PAGE analysis confirmed distinct LPS profiles for each bacterial strain, with shared bands at 35 and 40 kDa, along with additional lower molecular weight components in the P. aeruginosa LPS. Overall, the findings suggest that LPS from both E. coli and P. aeruginosa can influence various biochemical and morphological characteristics of alfalfa callus, offering potential implications for enhancing somatic embryogenesis in plant tissue culture systems.