STRUCTURAL AND FUNCTIONAL CHARACTERIZATION OF ORGANELLAR SMALL HEAT SHOCK PROTEINS FROM TOMATO (SOLANUM LYCOPERSICUM)

RENZI DJ; IUSEM N; ESCOBAR MR; BOGGIO SB; BADIA MB; SOSSI ML; VALLE EM

Salta

Congreso; SAIB-PABMB; 2019

SAIB

Chaperones belonging to the small heat shock protein (sHSP) family are ubiquitous and exhibit high expression levels after heat and other stress conditions. In plants, these proteins are especially abundant and diverse, and localized in the cytosol as well as in almost every organellar compartment. The presence of specific sHSP in organelles seems to be exclusive to plants, with a few exceptions. In tomato fruits, the accumulation of specific sHSP was postulated to be related to the protection against chilling postharvest injury. In this work, we focused on two organellar sHSP: sHPS23.8 and sHSP21.5, which are present in the mitochondria and endoplasmic reticulum of tomato, respectively. The mature proteins were cloned, expressed and purified to homogeneity. A structural characterization to investigate their oligomeric state in vitro was performed. Additionally, polyclonal antibodies against specific peptides of each of these proteins were used to detect changes in their abundance in fruit of wild type and transgenic tomato plants with altered levels of each of these proteins. In this sense, extracts from mature fruit before and after cold treatment were analyzed in order to elucidate their participation in the maturation of tomato fruit and their response to cold storage. Results indicated that the level of these proteins correlated with the chilling injury of the fruit, suggesting that the regulation of the organellar sHSP would be important for the protection mechanisms against chilling stress in tomato