Small Heat Shock Proteins, Morphological and Physiological Characteristics Associated with Heat Tolerance in Salvia (Salvia splendens)

Small heat shock proteins (sHSP) are a specific group of highly conserved proteins produced in almost all living organisms under heat stress. These sHSP have been shown to help prevent damage at the biomolecular level in plants. One of the greatest impediments to production of marketable herbaceous plants and their longevity is high temperature stress. The objectives of this experiment were to study the plant responses in terms of sHSP synthesis, single leaf net photosynthesis, total water-soluble carbohydrates (WSC), and overall growth for two S. splendens cultivars differing in performance under heat stress. `Vista Red' (heat tolerant) and `Sizzler Red' (heat sensitive) were exposed to short duration (3 hours) high temperature stresses of 30, 35, and 40 °C in growth chambers. Increasing the temperature to about 10 to 15 °C above the optimal growth temperature (25 °C, control) induced the synthesis of sHSP 27 in S. splendens. Expression of these proteins was significantly greater in the heat-tolerant vs. the heat-sensitive cultivar. Soluble carbohydrate content was greater in `Vista Red', and in both the cultivars raffinose was the primary soluble carbohydrate in heat-stressed plants. Overall growth of plants was significantly different in the two cultivars studied in terms of plant height, stem thickness, number of days to flower, and marketable quality. The better performance of `Vista Red' under heat stress was attributed to its morphological characteristics, including short stature, thicker stems and leaves. sHSPs and WSC are also found to be associated with heat tolerance and heat adaptation in S. splendens.

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The Heat-Shock Response and Expression of Heat-Shock Proteins in Wheat Under Diurnal Heat Stress and Field Conditions

Functional Plant Biology ◽

10.1071/pp9940857 ◽

1994 ◽

Vol 21 (6) ◽

pp. 857 ◽

Cited By ~ 14

Author(s):

HT Nguyen ◽

CP Joshi ◽

N Klueva ◽

J Weng ◽

KL Hendershot ◽

...

Keyword(s):

Heat Stress ◽

Heat Shock ◽

Heat Shock Proteins ◽

Heat Tolerance ◽

Heat Shock Response ◽

Field Conditions ◽

Shock Response ◽

Heat Tolerant ◽

Shock Proteins

The occurrence of heat-shock proteins (HSPs) in response to high temperature stress is a universal phenomenon in higher plants and has been well documented. However, in agriculturally important species, less is known about the expression of HSPs under natural environments. A review of the heat-shock response in wheat (Triticum aestivum L.) is presented and recent results on the expression of wheat HSPs under diurnal stress and field conditions are reported. In the field experiment, flag leaf blade temperatures were obtained and leaf blades collected for northern blot analysis using HSP 16.9 cDNA as a probe. Temperatures of leaf blades ranged from 32 to 35�C under the tested field conditions at New Deal near Lubbock, Texas. Messenger RNAs encoding a major class of low molecular weight HSPs, HSP 16.9, were detected in all wheat genotypes examined. The results suggested that HSPs are synthesised in response to heat stress under agricultural production, and furthermore, that HSPs are produced in wheats differing in geographic background. In the controlled growth chamber experiment, HSP expression in two wheat cultivars, Mustang (heat tolerant) and Sturdy (heat susceptible) were analysed to determine if wheat genotypes differing in heat tolerance differ in in vitro HSP synthesis (translatable HSP mRNAs) under a chronic, diurnal heat-stress regime. Leaf tissues were collected from seedlings over a time-course and poly (A)+RNAs were isolated for in vitro translation and 2-D gel electrophoresis. The protein profiles shown in the 2-D gel analysis revealed that there were not only quantitative differences of individual HSPs between these two wheat lines, but also some unique HSPs which were only found in the heat tolerant line. This data provides evidence of a correlation between HSP synthesis and heat tolerance in wheat under a simulated field environment and suggests that further genetic analysis of HSPs in a segregating population is worthy of investigation. In conclusion, the results of this study provide an impetus for the investigation of the roles of HSP genes in heat tolerance in wheat.

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Immunomodulation of function of small heat shock proteins prevents their assembly into heat stress granules and results in cell death at sublethal temperatures

The Plant Journal ◽

10.1111/j.1365-313x.2004.02290.x ◽

2004 ◽

Vol 41 (2) ◽

pp. 269-281 ◽

Cited By ~ 42

Author(s):

Sergey Miroshnichenko ◽

Joanna Tripp ◽

Uta zur Nieden ◽

Dieter Neumann ◽

Udo Conrad ◽

...

Keyword(s):

Cell Death ◽

Heat Stress ◽

Heat Shock ◽

Heat Shock Proteins ◽

Stress Granules ◽

Small Heat Shock Proteins ◽

Shock Proteins

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In vivo evidence from an Agrostis stolonifera selection genotype that chloroplast small heat-shock proteins can protect photosystem II during heat stress

Functional Plant Biology ◽

10.1071/pp01191 ◽

2002 ◽

Vol 29 (8) ◽

pp. 935 ◽

Cited By ~ 70

Author(s):

Scott A. Heckathorn ◽

Samantha L. Ryan ◽

Joanne A. Baylis ◽

Dongfang Wang ◽

E. William Hamilton III ◽

...

Keyword(s):

Heat Stress ◽

Electron Transport ◽

Heat Shock ◽

Heat Shock Proteins ◽

Agrostis Stolonifera ◽

Small Heat Shock Proteins ◽

O2 Evolution ◽

Shock Proteins ◽

Tolerant Genotype

Previous in vitro experiments indicated that chloroplast small heat-shock proteins (sHsp) could associate with thylakoids and protect PSII during heat and other stresses, possibly by stabilizing the O2-evolving complex (OEC). However, in vivo evidence of sHsp protection of PSII is equivocal at present. Using previously characterized selection genotypes of Agrostis stolonifera Huds. that differ in thermotolerance and production of chloroplast sHsps, we show that both genotypes contain thylakoid-associating sHsps, but the heat-tolerant genotype, which produces an additional sHsp isoform not made by the sensitive genotype, produces a greater quantity of chloroplast and thylakoid sHsp. Following a pre-heat stress to induce sHsps, in vivo PSII function decreased less at high temperatures in the tolerant genotype. Differences in PSII thermotolerance in vivo were associated with increased thermotolerance of the OEC proteins and O2-evolving function of PSII, and not with other PSII proteins or functions examined. In vivo cross-linking experiments indicated that a greater amount of sHsp associated with PSII proteins during heat stress in the tolerant genotype. PSII was the most thermosensitive component of photosynthetic electron transport, and no differences between genotypes in the thermotolerance of other electron transport components were observed. These results indicate that in vivo chloroplast sHsps can protect O2 evolution and the OEC proteins of PSII during heat stress.

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