Heat stress is a major environmental constraint for crop production worldwide. To respond to and cope with heat stress, plants synthesize heat shock proteins (HSPs), which are often molecular chaperones and are under the control of heat stress transcription factors (HSFs). Very little is known about the upstream regulators of HSFs. In a forward genetic screen for regulators of C-REPEAT BINDING ...

The molecular chaperone heat shock protein101 (HSP101) is required for acquired thermotolerance in plants and other organisms. To identify factors that interact with HSP101 or that are involved in thermotolerance, we screened for extragenic suppressors of a dominant-negative allele of Arabidopsis thaliana HSP101, hot1-4. One suppressor, shot1 (for suppressor of hot1-4 1), encodes a mitochondria...

Heat stress and ultraviolet light in the UVB range ("sunburn spectrum," 290-320 nm) were found to alter the synthesis of specific proteins in cultured keratinocytes derived from mouse skin. Using giant two-dimensional gels, approximately 2,000 cellular polypeptides labeled with [35S]methionine at 4-5 h after exposure to heat or to UVB were analyzed. Cells conditioned at sublethal temperatures (...

This study concerns the thermotolerance of spores of mesophilic fungi isolated from a tropical semi-arid habitat subject to dry season fire in the Western Ghats, southern India. Among 25 species of Ascomycota isolated from leaf litter, nine were able to grow after incubation in a drying oven for 2h at 100°C; the spores of two of these species survived 2h incubation at 110°C, and one survived ex...

Hsp78, a member of the family of Clp/Hsp100 proteins, exerts chaperone functions in mitochondria of S. cerevisiae which overlap with those of mitochondrial Hsp70. In the present study, the role of Hsp78 under extreme stress was analyzed. Whereas deletion of HSP78 does not affect cell growth at temperatures up to 39 decrees C and cellular thermotolerance at 50 degrees C, Hsp78 is crucial for mai...

Plants have evolved a range of cellular responses to maintain developmental homeostasis and to survive over a range of temperatures. Here, we describe the in vivo and in vitro functions of BOBBER1 (BOB1), a NudC domain containing Arabidopsis (Arabidopsis thaliana) small heat shock protein. BOB1 is an essential gene required for the normal partitioning and patterning of the apical domain of the ...

Genome-wide gene-expression studies have shown that hundreds of yeast genes are induced or repressed transiently by changes in temperature; many are annotated to stress response on this basis. To obtain a genome-scale assessment of which genes are functionally important for innate and/or acquired thermotolerance, we combined the use of a barcoded pool of ~4,800 nonessential, prototrophic Saccha...

Male reproductive tissues are more sensitive to heat stress (HS) compared to vegetative tissues, but the basis of this phenomenon is poorly understood. Heat stress transcription factors (Hsfs) regulate the transcriptional changes required for protection from HS In tomato (Solanum lycopersicum), HsfA2 acts as coactivator of HsfA1a and is one of the major Hsfs accumulating in response to elevated...

Key evolutionary events associated with invasion success are traditionally thought to occur in the introduced, rather than the native range of species. In the invasive ant Wasmannia auropunctata, however, a shift in reproductive system has been demonstrated within the native range, from the sexual non-dominant populations of natural habitats to the clonal dominant populations of human-modified ...

Nitric oxide (NO) is a key signaling molecule in plants. This analysis of Arabidopsis thaliana HOT5 (sensitive to hot temperatures), which is required for thermotolerance, uncovers a role of NO in thermotolerance and plant development. HOT5 encodes S-nitrosoglutathione reductase (GSNOR), which metabolizes the NO adduct S-nitrosoglutathione. Two hot5 missense alleles and two T-DNA insertion, pro...