The Use Of Antimicrobials In Plant Tissue Culture

Plant antibiotics produced through tissue culture • Antibiotics: • Antibiotics are substances produced by certain microorganisms that suppress the growth of other microorganisms and eventually destroy them.

Antimicrobials in Plant Tissue Culture Antibiotics (Antimicrobials) • Bacteristatic–Inhibit bacterial growth; bacteria viable but “dormant”. Growth resumes in antibiotic-free medium. • Bactericidal –Lethal to bacteria; no subsequent growth in antibiotic-free medium • Antifungal (Antimycotics) –Fungistatic& Fungicidal • Broad-spectrum Antimicrobials –Inhibit or eliminate bacteria and fungi. • Antiviral –Inactivate virus

Ideally, Antibiotics in Plant Tissue Culture are: • Stable Broad spectrum of activity • Unaffected by media pH or components of bacterial resistance • Inexpensive Lethal to microbe • Minimal side effects • (no phytotoxicity) Usable in combinations

Low chance

Effect on Multiplication • Grading antibiotics based on their inhibitory effect on plant growth (reduced multiplication rate in vitro): • Most Inhibitory • Streptomycin ⇒Polymyxin-B ⇒ • Rifampicin⇒Carbenicillin – Least Inhibitory

Do I Have to Add Antibiotics to the Medium? – Not necessarily…

• Stock Plant Treatment–Reduced phytotoxicity – •Heveashoots-tips ⇒inhibited growth w/ antibiotics in medium. – •No inhibition if stock plant sprayed every 2 days for 2 weeks before culture. – •Contamination controlled

• Other studies have shown reduced bacterial growth in shoot-tips & buds w/ regular antibiotic treatments to stock pants.

Bacteristatic

Bactericidal

Reversible inhibition of bacterial growth.

Lethal to Bacteria.

May have bactericidal activity at high concentrations.

Bacteristaticat low concentrations.

Includes: Choramphenicols Tetracyclines Macrolides (Erythromycin)

Includes: Aminoglycosides Cephalosporins Penicillins Polymyxins(Polymyxin-B) Rifamycins(Rifampicin)

Antifungals(Antimycotics) – Amphotericin B • Cycloheximide

• Nystatin • Griseofulvin – Petachloronitrobenzene(PCNB)

• Thiabendazole

Wide-Spectrum Antimicrobials • PPM™(Plant Preservative Mixture) • 8-Hydroxyquinoline

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