Evaluación de la expresión de los genes que codifican para proteínas de choque térmico HSP de plántulas de arroz (Oryza Sativa) irradiadas con 60co tolerante, resistente y susceptible al estrés por altas temperaturas

Abstract

Plants are organisms that are constantly exposed to different types of abiotic stress altering their optimum development and therefore the productivity of crops is affected. Due to the stress generated by the temperature variation, the plants have developed a group of proteins known as heat shock proteins (HSPs), which act as molecular chaperones, helping the plant in the processes of adequate protein folding, transport through Of membranes, modulation of the protein activity and regulation of protein degradation, thus contributing, tolerance to the plant against the constant change of temperature. The present work evaluated the expression of genes encoding the heat shock proteins sHsp's (Hsp16.9, Hsp18, Hsp26.7), Hsp70 and Hsp90 in rice varieties (Oryza sativa): Fedearroz 473, Fedearroz Mocarí and Advanced line Lv 1645 that have been irradiated with a dose of 60 Gy of 60 Co in its first generation. For this purpose, hydroponic cultures with Yang medium were carried out for each of the varieties; Once they reached the seedling stage were subjected to heat stress for one day from 11:00 am to 3:10 p.m. as follows: a control treatment (TC) at a temperature of 28 ° C, a moderate stress treatment ( T1) at 35 ° C and a high stress treatment (T2) at 42 ° C. During each treatment three RNA extractions and total proteins were performed for each variety at three different times; The first extraction was done at 11:10 am, the second at 1:10 pm and the last at 3:10 pm. The RNA was quantified through the Thermo Scientific NanoDrop 2000c UV-Vis spectrophotometer, subsequently the samples of better characteristics were selected for the development of the work. Through the real-time polymerase chain reaction (q-RT-PCR) an absolute quantification of the genes of interest was made; The total proteins were quantified by the Bradford method, in addition 12.5% sodium dodecylsulfate polyacrylamide gels (SDS-PAGE) were made. The results showed that the three genotypes F473, Mocarí Lv 1645 do not present significant differences in the growth of the seedlings during the four hours of exposure to the heat stress due to high temperatures, on the other hand a dose of 60 Gy of Co generates physical alterations in The Mocarí and Lv 1645 varieties, at the level of heat shock protein expression (Hsp) in the three genotypes, this increases as temperature increases as a protective mechanism of the seedling and the expression of these genes is related to tolerance At high temperatures, being Fedearroz 473 tolerant, Mocari resistant and Advanced line 1645 susceptible to high temperatures. At the protein level it is concluded that the proteins with the highest intensity correspond to 50 kDa, being corresponding to glutelinic proteins that constitute between 70 and 90% of total proteins in rice.73/5000