Poster: Temperature responses

Abs # 133: Diversification of chloroplast small heat shock proteins in plants

Presenter:	Qureshi, Samina N, snq2@msstate.edu
Authors	Qureshi, Samina N (A)   Dawn, Luthe  (A)
Affiliations:	(A): Dept. of Molecular Biology & Biochemistry, Mississippi State University

It has been demonstrated that the chloroplast small heat shock proteins (Cp-sHSP) are correlated with increased thermotolerance in a number of plant species. They appear to improve heat tolerance by protecting Photosystem II during high temperature stress. Our research is focused on determining the functional significance of the qualitative and quantitative variation in Cp-sHSPs in plant species and ecotypes with differing levels of heat tolerance. To accomplish this we are isolating and characterizing the Cp-sHSP genes from two heat-sensitive species Agrostis stononifera, Chenopodium album (New York and Mississippi ecotypes), two moderately heat-tolerant species,Spartina alterniflora and Amaranthus retroflexus, and two very heat-tolerant species, Agave americana and Ferocactus wislizenii. Gene-specific primers were designed from the methionine-rich region of the Cp-sHSP that directed the amplification of 300 bp fragments, which were cloned and sequenced. These sequences showed significant similarity with Cp-sHSPs from other closely related species. The fragments were used for PCR-based genome walking so that the complete genes could be isolated. By characterizing these Cp-sHSPs and their expression, we will determine if those found in the very heat-tolerant plants have unique characteristics."