EXPRESSION PROFILING OF HEAT SHOCK PROTEIN GENES AS KEY EARLY RESPONDERS TO HEAT STRESS IN INDIGENOUS LETTUCE (LACTUCA SATIVA L)

Abstract

Global warming-induced high temperatures can negatively impact lettuce’s productivity as a cool-season crop. Plants’ heat shock protein (HSPs) serves as molecular chaperones, facilitating stress tolerance and protein stability, are critical to plant survival in the context of heat stress (HS) aggravated by global warming. In this study, we determine the expression pattern of HSP genes i.e. LsHSP70A, LsHSP70B, LsHSP83A and LsHSP83B in indigenous lettuce (lactuca sativa L.) by quantitative real-time PCR (qRT-PCR) following temperature stress. The four HSP genes exhibited distinctive expression patterns in response to HS exposure at 37ºC at 1, 4, 16 and 24 hours. The findings showed that the expression levels of the two HSP genes, LsHSP83A and LsHSP83B were significantly upregulated at all time points after heat stress, whereas LsHSP70A, LsHSP70B revealed variable expression patterns exhibiting both up- and downregulation at various time points, suggesting diverse regulatory mechanisms. Our study showed putative early heat-responsive HSP genes in lettuce, which could be possible candidates for breeding efforts to create heat-tolerant lettuce cultivars.