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EGTA vs EDTA and high phenol PH for RNA isolation from small amount of root tips - (Jan/29/2007 )

I am optimizing protocol to isolate RNA from small (very small, <100 mg) amount of tomato root tips. I came across a protocol which uses EGTA in stead of EDTA and suggests to use high PH (9.0) of phenol. When I looked on the literature, I found that EGTA chelates Ca+ efficiently than EDTA. I didn't find any specific advantage of using EGTA over EDTA.

In the mean time, I am little bit confused with the high pH of Phenol, as I know most of the protocols suggest lower pH for RNA and little higher pH for DNA. Do you guys have any suggestion about this.

Have any of you used Trizol to isolate RNA from plant roots. Please suggest me.


EDTA has an higher affinity for Mg++

are your sure about your pH? usually such pH is for DNA extraction (but RNA goes in it as well).
For RNA only it's 4.5-4.8 pH values which are used... dry.gif
i think the pb which may rise with plant roots, is that they may be difficult to efficiently be lysed.
Ty optimize breaking and lysis of your roots, and trizol will be very great.