Submitted to: HortScience
Publication Type: Abstract Only
Publication Acceptance Date: 2/23/2005
Publication Date: 7/15/2005
Citation: Slovin, J.P. 2005. Hsp101 in the model strawberry, fragaria vesca. Hortscience.
Technical Abstract: Our lab has initiated a project to determine if specific proteins expressed by strawberry in response to heat stress function as part of the thermotolerance system and if they do, to evaluate the potential for utilizing these proteins to improve crop stress responses. Specifically, we are developing better tools for investigating the role of heat shock proteins (HSPs) or other gene products in strawberry thermotolerance. These tools include an inbred diploid testing system, assays for thermotolerance that have physiological and/or agricultural relevance, EST sequence data with which to construct a small microarray for assaying the stress state of experimental plants, and molecular markers for heat tolerance. We have developed an inbred line, 5AF7, of the diploid strawberry, Fragaria vesca, to use for testing gene function because the diploid genome is small (164Mbp), the life cycle of the plant is short (about 4 months), the plant size is small (a plant will produce fruit in a 4 inch pot), some genetic work is already done, Fragaria vesca is transformable with Agrobacterium tumefasciens, and results should be transferable to the commercial octoploid varieties. A cDNA library was constructed in the pCMVsport 6.1 vector (Invitrogen) using combined RNA from batches of aseptically grown F. vesca seedlings treated to various elevated temperature regimes. Over 1500 EST sequences from the library have been deposited in GenBank and are available annotated at the Fragaria database at the ESTAP website (http://staff.vbi.vt.edu/estap/index.shtml). HSP101 is known to be involved in thermotolerance in Arabidopsis (Queitsch et al., 2000, Plant Cell 12:479). A PCR fragment for HSP101 was generated from F. vesca with degenerate primers, and used to obtain a full-length cDNA clone from the library. Primers spanning an intron were designed for RTPCR from the sequence of the cDNA. Semi-quantitative RTPCR indicates that HSP101 is expressed constitutively in young leaves at 25 ºC and is not induced at moderately higher temperatures (32 ºC) even after 5 hr. Induction occurs within 1 hr at 37 ºC.