identify the bacteria like gram nature & on basic medias. use antibiotic against the same confirming that the antibiotic will not hamper your seed performance (reading about the same may help), also make sure your media is sterile before use or as an additional precaution filter sterilize it just before use.

Thanks madam.

Dear Pamoda,

Cant you germinate on LB plates itself? It will be easy to reduce/eliminate the indigenous contamination too. Antibiotics are not so effectively on solid medium as many part of ex-plant doesn't touch or in case of indigenous contamination. And due course of incubation some antibiotics get in-effective. After 4-5 days you can transfer the uncontaminated seed on MS medium.

I would first of all make sure that it's really the contamination that kills your explants rather than some problem with growth promoters you're adding to your medium. Prepare a microscope slide with part of your dead explant plus water and take a look under regular light microscope, you should be able to see bacteria if they're really the problem. How are you germinating the seeds? If you are really convinced that bacteria are the issue you can always play with your sterilization protocol,  Cl2 gas for example is usually very effective (but will cause some seed mortality).

As a really short potential solution, we add timentin to our MS plates to minimise bacterial growth - it doesn't affect the plants (Arabidopsis) and it kills E. coli and Agrobacterium.

But the other advice here is much more in depth and useful :)

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Hi Dassanayake

I think, you can read this paper "Understanding and Managing Cell Culture Contamination Technical"

https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=2&ved=0ahUKEwiX8qiH8ubQAhXGKCwKHWfiDsgQFggiMAE&url=http%3A%2F%2Fwww.level.com.tw%2Fhtml%2Fezcatfiles%2Fvipweb20%2Fimg%2Fimg%2F20297%2Fcontamination-COR.pdf&usg=AFQjCNE5NhYq415BoElW6UuqdNj0b0e_KA&sig2=pLJvowcvrSW29WQe2IHX_w&cad=rja

Thank you Kuldeep, Joanna, Joanne and Laith. 

You are welcome

Dear researcher

Antibiotics should not be used routinely in cell culture, because their continuous use encourages the development of antibiotic resistant strains and allows low-level contamination to persist, which can develop into full-scale contamination once the antibiotic is removed from media . Further, some antibiotics might cross react with the cells and interfere with the cellular processes under investigation.

Antibiotics should only be used as a last resort and only for short term applications, and they should be removed from the culture as soon as possible. 

Regards

As an effective and alternative solution, sterilize your plant seeds with 70% ethanol for 1 min, 20% bleach plus one droplet of soap for 20 min, and washing with sterile water three times, 5 min each. It works for a variety of plant seeds and even explants.

First of all, ethanol is not sufficient method for seed sterilization. You can try Dihydrostreptomycin, sodium hypochlorite and UV light.

Pamoda Dassanayake

From explants, Bacterial contamination can be eliminated through careful sterilization procedures. After culture establishment, it is in our hand to avoid contamination. Clean hand and Careful handling is essential to get bacterial contaminant-free cultures. I would suggest not using antibiotics to get rid of bacteria in TC.

Proper sterilization of seeds explants is essential in this case. Once culture will establish, careful handing is the key factor to avoid contamination.

Pamoda Dassanayake I'd bring many explants for sterilization to find a healthy source of explant instead of playing with antibiotics