11 páginas, 4 figuras, 2 tablas.Transcriptome sequencing with next-generation sequencing technologies has the potential for addressing many longstanding
questions about the biology of sponges. Transcriptome sequence quality depends on good cDNA libraries, which
requires high-quality mRNA. Standard protocols for preserving and isolating mRNA often require optimization for unusual
tissue types. Our aim was assessing the efficiency of two preservation modes, (i) flash freezing with liquid nitrogen
(LN2) and (ii) immersion in RNAlater, for the recovery of high-quality mRNA from sponge tissues.We also tested whether
the long-term storage of samples at )80 C affects the quantity and quality of mRNA. We extracted mRNA from nine
sponge species and analysed the quantity and quality (A260 ⁄ 230 and A260⁄ 280 ratios) of mRNA according to preservation
method, storage time, and taxonomy. The quantity and quality of mRNA depended significantly on the preservation
method used (LN2 outperforming RNAlater), the sponge species, and the interaction between them.When the preservation
was analysed in combination with either storage time or species, the quantity and A260 ⁄ 230 ratio were both significantly
higher for LN2-preserved samples. Interestingly, individual comparisons for each preservation method over time indicated
that both methods performed equally efficiently during the first month, but RNAlater lost efficiency in storage times longer
than 2 months compared with flash-frozen samples. In summary, we find that for long-term preservation of samples, flash
freezing is the preferred method. If LN2 is not available, RNAlater can be used, but mRNA extraction during the first
month of storage is advisedThis work has been supported by a
Marie Curie Fellowship to A.R., a FPI pre-doctoral Fellowship
(BES-2008-003009) of the Spanish Ministry of Science and Innovation
and a grant included in the project Benthomics
(CTM2010-22218-C02-01) to A.R.R.-P., and a Fulbright of the
Spanish Ministry of Science and Innovation (EX2009-0128) to
S.C. This material is based upon work supported by a grant of
the Marie Curie Outgoing Fellowship Program to A.R., by the
National Science Foundation under Grant No. DEB #0844881 to
G.G, and NSERC Discovery and Ship Time grants to S.P.L.Peer reviewe
