Elimination of in vitro bacterial contaminants in shoot cultures of ‘MRS 2/5’ plum hybrid by the use of Melia azedarach extracts

Abstract

The antimicrobial activity of leaf and callus extracts of Melia azedarach was tested on in vitro shoot cultures of the peach rootstoch 'MRS 2/5' (Prunus cerasifera × Prunus spinosa) that were heavily contaminated with Sphingomonas paucimobilis (Sp) and Bacillus circulans (Bc). The extracts were filter-sterilised and added at 0%, 1%, 5%, 10% and 20% to a modified Murashige and Skoog proliferation medium previously autoclave-sterilised. Up to about 17% shoots died with 10-20% extract, except for Spcontaminated shoots, whose survival was reduced to 50% after treatment with 20% extract. No shoots died with 1% to 5% supplement. The undiluted leaf extract showed bactericidal activity on plated Sp and Bc isolates. The homogenates of shoots randomly collected from treated cultures were processed for bacterial colony counting. Thus the 10% supplement was the best treatment for ridding Bc-contaminated cultures of bacteria (although 5% had a similar bactericidal effect), and allowing shoot growth and proliferation comparable to controls at the fifth subculture on a standard medium, while 20% extract was needed to eliminate Sp, and could induce higher growth and proliferation rates in surviving shoots than in untreated cultures. Callus extract was ineffective. The bactericidal activity of the leaf extract seemed attributable to a synergistic effect of azadirachtin with other unidentified compounds present in the extract.

Eradication of endophytic bacteria via treatment for axillary buds of Petunia hybrida using Plant Preservative Mixture (PPMTM)

“…In a plant tissue culture laboratory, this bacterium could be a contaminant of inadequately sterilised instruments or water. The negative effects of S. paucimobilis on the some Prunus genotypes has been shown as reduced shoot and root development, lower proliferation and higher CO 2 concentration in the culture jars (Marino et al 1996(Marino et al , 2009). In our laboratory, S. paucimobilis was found on accidentally infected Petunia plantlets.…”

Optimasi sterilisasi permukaan eksplan stek mikro tanaman karet Optimization of surface sterilization on rubber microcutting explan

“…Kontaminan berupa bakteri, meskipun pertumbuhannya lebih lambat dapat memproduksi metabolit yang toksik terhadap eksplan, memodifikasi Ph media sehingga eksplan mengalami nekrosis dan *) Penulis korespondensi:imartiansyah6311@yahoo.com menghambat penyerapan nutrisi oleh eksplan (Singh et al, 2011). Kontaminan akan menghambat pertumbuhan eksplan dan menyebabkan kehilangan eksplan yang jumlahnya bisa sangat besar sehingga memperlambat proses perbanyakan serta meningkatkan biaya produksi kultur jaringan skala komersial (Marino et al, 2009).…”

“…Menurut Akin-Idowu et al (2009), kontaminasi pada kultur jaringan terjadi pada awal inisiasi eksplan yang terkait dengan tempat dan waktu pengambilan eksplan. Kontaminasi mikroba terutama bakteri menjadi masalah utama pada kultur jaringan tanaman (Marino et al, 2009). Kontaminasi bakteri seringkali sulit dideteksi pada awal kultur karena berada di dalam jaringan tanaman.…”

Atuação da manifestação bacteriana no desenvolvimento in vitro de clones de Eucalyptus benthamii Maiden & Cambage

“…Pesquisas, entretanto, relatam que mesmo sem manifestação aparente existem comunidades endofíticas colonizando os tecidos de plantas consideradas axênicas (ABREU-TARAZI et al, 2010;ALMEIDA et al, 2009;DIAS et al, 2009;ESPOSITO-POLESI, 2010;ESPOSITO-POLESI, 2011;ALTAN;BIAVATI, 1996;MARINO et al, 2009;PIRTTILÄ et al, 2008;THOMAS, 2004;THOMAS et al, 2007a;THOMAS et al, 2008a), sendo a estrutura de comunidades endofíticas alteradas de acordo com seus nichos de colonização e períodos de cultivo da planta hospedeira (ABREU-TARAZI, 2010).…”

“…Os dados de todos os experimentos foram submetidos ao teste de Bartlett Log 10 do U'FC.mL -1 Log 10 do UFC.mL -1 DO = 0,3749 -0,051568x + 0,003313x 2 -0,00004771x 3 r² = 0,97 UFC = 5798,73-1146,24x+72,23x 2 -1,12x 3 r² = 0,97 DO = -0,02194 + 0,0006457x 2 -0,000008050x 3 r² = 0,99 UFC = 0,071839 + 0,002572x 2 r² = 0,99 DO= 0,0266 -0,0133x + 0,002239x 2 -0,000136x 3 + 0,0000035x 4 -0,0000000296x 5 r² = 0,98 UFC = -26412,25 + 211,40x 2 -3,74x 3 r² = 0,62 DO = 0,00368 + 0,0207x -0,00853x 2 + 0,00205x 3 -0,000127x 4 + 0,000002280x 5 r² = 0,91 UFC = -2639,18 + 113,03x 2 -4,55x 3 r² = 0,86 DO = -0,01234 + 0,01445x + 0,001941x 2 -0,00006487x 3 r² = 0,98 UFC = -7388 + 2744x r² = 0,97 DO = -0,002539 + 0,03827x + 0,003953x 2 -0,00025x 3 + 0,000003789x 4 r² = 0,98 UFC = -9665,16 + 3,01x 3 r² = 0,95 Biavati (1996); Marino et al (2009); Thomas (2004); Thomas et al (2007a).…”