Karakterizacija antimikrobnih supstanci prirodnih izolata Bacillus sp. za primenu u biološkoj kontroli fitopatogenih bakterija i gljiva
Characterization of antimicrobial substances from natural isolates of Bacillus sp. for application in biological control of plant pathogenic bacteria and fungi
Doktorand
Dimkić, Ivica Z.Mentor
Stanković, SlavišaČlanovi komisije
Berić, TanjaFira, Đorđe
Lozo, Jelena
Stević, Tatjana
Metapodaci
Prikaz svih podataka o disertacijiSažetak
Bolesti biljaka izazvane infekcijama patogenim bakterijama i gljivama mogu
dovesti do smanjenja kapaciteta biljnog rasta ili naneti mnogo ozbiljniju štetu dovodeći
do smrti biljaka i značajnih gubitaka u proizvodnji hrane. Veliki broj istraživanja je u
poslednje vreme posvećen proučavanju roda Bacillus kao producenta sekundarnih
metabolita u kontroli različitih biljnih patogena.
Analizom diverziteta gena odgovornih za produkciju neribozomalno sintetisanih
lipopeptida kolekcije od 205 Bacillus sp. izolata utvrđeno je da je za najveći broj izolata
(171) ustanovljen DNK fragment očekivane dužine, koji odgovara bacilomicin D
sintetazi, dok su u sličnom broju izolata dobijeni fragmenti očekivanih dužina za
kurstakinske (154) i surfaktinske operone (142), a prisustvo iturinskog operona
ustanovljeno je kod 84, odnosno 59 izolata u slučaju gena za fengicin sintetazu.
Prisustvo svih pet biosintetičkih operona je potvrđeno kod 11 izolata.
Najveća produkcija antimikrobnih jedinjenja za pet izabra...nih izolata je pokazana
u eksponencijalnoj ili ranoj stacionarnoj fazi rasta. Prikazan je jak antifungalni efekat
lipopeptidnih ekstrakata prema više od 30 testiranih gljiva, sa najnižim zabeleženim
minimalnim inhibitornim koncentracijama od 0,008 mg/ml protiv Fusarium semitectum,
kao i izražen antibakterijski potencijal, naročito protiv fitopatogenih vrsta rodova
Xanthomonas i Pseudomonas, sa najnižom minimalnom inhibitornom koncentracijom
od 0,06 mg/ml. Proučavanje interakcija pojedinačnih lipopeptidnih ekstrakata u
međusobnim, kao i u kombinacijama sa etarskim uljima, ukazalo je na postojanje
sinergističkog efekta za neke kombinacije u in vitro, odnosno aditivnog efekta u in situ
uslovima, na bakterijskim i fungalnim patogenima. Utvrđivanjem direktnog
antagonističkog efekta lipopeptidnih jedinjenja in planta, ustanovljena je značajna
redukcija nekroze tkiva listova Arabidopsis thaliana L. i Beta vulgaris L., tretiranih
bakterijskim patogenima. Takođe, u in situ uslovima postignuta je značajna redukcija
nekroze tkiva ploda jabuke izazvana fungalnom infekcijom...
Plant diseases caused by infection with pathogenic bacteria and fungi can lead to
the reduction in the capacity of plant growth or can cause far more serious damage,
leading to the death of plants and significant losses in food production. Numerous recent
studies are devoted to the genus Bacillus as a producer of secondary metabolites in the
control of different plant pathogens.
In the analysis of diversity of genes responsible for the nonribosomal
synthesized lipopeptides in collections of 205 Bacillus sp. isolates, for the largest
number of isolates (171) the DNA PCR fragment of the expected length, corresponding
to bacillomycin D synthases was obtained, while in a similar number of isolates
fragments of the expected length for kurstakin (154) and surfactin operons (142) were
obtained. The presence of iturin operon in the 84 or 59 isolates in the case of the gene
for fengycin synthetase, was also found. The presence of all five biosynthetic operons in
the 11 isolates was confirmed as... well.
The maximum production of antimicrobial compounds for five selected isolates
in exponential or early stationary phase of growth was determined. Strong antifungal
effect of lipopeptide extracts towards more than 30 fungi tested, with lowest recorded
minimal inhibitory concentrations of 0,008 mg/ml against Fusarium semitectum, as well
as expressed antibacterial potential, in particular against phytopathogenic species of the
genera Pseudomonas and Xanthomonas, with the lowest minimum inhibitory
concentration of 0,06 mg/ml was determined. In the analysis of the interaction of
individual lipopeptide extracts mutually, as well as in combination with essential oils,
the existence of a synergistic effect in vitro respectively additive effect in situ, on
bacterial and fungal pathogens, for some combinations were shown. Establishing a
direct antagonistic effect of lipopeptide compounds in planta, significant reduction in
necrotic lesions of leaves of Arabidopsis thaliana L. and Beta vulgaris L. treated with
bacterial pathogens was obtained. Also, a significant reduction in necrotic lesions of
apple fruit caused by fungal infection in situ was determined...