Rapid induction of small heat shock proteins improves physiological adaptation to high temperature stress in peanut

Abstract

With the changing climatic scenario and increasing global mean temperature, heat stress became a major limiting factor for today's agriculture. To identify the underlying mechanism associated with heat tolerance in peanut, two experiments (field and growth chamber) were conducted with four genotypes (ICGS 44, GG 7, AK 159 and DRG 1) having differential high temperature stress sensitivity. Field grown plants under three different temperature (D1, D2 and D3) regimes simulated three temperature treatment effects with a variability of 3–4/4–5°C in mean day/night temperature, respectively. In growth chamber, imposition of heat shock (10°C above ambient inside growth chamber) revealed not only rapid induction (within 0.5 hr) of HSPs, especially small HSPs (HSP 17, HSP 40) in tolerant genotypes, but also its sustenance for longer duration (2 hr), which might help them to have better physiological adaptation strategies under high temperature stress. This was evident from significant advancement in phenophases observed with increase in temperature by 15–18 days at physiological maturity, while pollen viability and membrane stability reduced below 50% and 41%, respectively in DRG 1 with increase in mean day/night temperature. Maintenance of higher photosynthesis and transpiration rate and stomatal conductance helped the tolerant genotype ICGS 44 to keep relatively cooler canopy and higher photosynthates, ensuring better physiological condition in this genotype under heat stress. Significant increase (~2.5‐fold) in inositol and hexoses (glucose and fructose) content and reduction (>50%) in sucrose content in leaf tissues indicated degradation of storage carbohydrates for improved osmotic adjustment especially in tolerant genotypes under elevated temperature.

Identification and Characterization of Contrasting Genotypes/Cultivars for Developing Heat Tolerance in Agricultural Crops: Current Status and Prospects

“…Likewise, in peanut, the best-characterized aspect of acquired thermotolerance is HSP production, with ICGS76, COC038, and COC068 selected as heat-tolerant genotypes and COC812, COC166, Tamrun OL 02, and Spanco selected as heat-sensitive (Selvaraj et al, 2011). In another study, heat-tolerant peanut genotype ICGS 44 showed higher HSP expression throughout the stress period than heatsensitive genotypes AK 159 and DRG 1 (Chakraborty et al, 2018). Comparison of expression of heat shock proteins in wheat cultivars (Katya and Sadovo) under combined heat and drought stress (40 • C/56%) reported 100% elevation of HSP100 and HSP70 as compared to 60 and 10% elevation under individual drought and heat stress in tolerant cultivar Katya (Grigorova et al, 2011).…”

Combining Physiological and Metabolomic Analysis to Unravel the Regulations of Coronatine Alleviating Water Stress in Tobacco (Nicotiana tabacum L.)

“…Glucose and fructose are two of the main reducing sugars that are responsible for plant signal transduction to modulate drought tolerance [42]. Elevated level of glucose and fructose is involved in turgor maintenance [43] and associated with improved stress tolerance in many plants [44][45][46]. Mannose has been shown to be an important compatible osmolyte and play a role in protein glycosylation in plants [47].…”

Comparative transcriptome analysis uncovers different heat stress responses in heat-resistant and heat-sensitive jujube cultivars

“…Many HSPs function as molecular chaperones [13] and serve important roles in the regulation of the protein quality by renaturing various proteins that have been denatured by heat stress [14]. In peanuts, accumulation of small HSPs could improve its resistance to heat [15].…”