Insights into genomic variations in rice Hsp100 genes across diverse rice accessions.

The Hsp101 gene is present across all sequenced rice genomes. However, as against Japonica rice, Hsp101 protein of most indica and aus rice contain insertion of glutamic acid at 907th position. The understanding of the heat stress response of rice plants is important for worldwide food security.

Meta-QTL and haplo-pheno analysis reveal superior haplotype combinations associated with low grain chalkiness under high temperature in rice.

Chalk, an undesirable grain quality trait in rice, is primarily formed due to high temperatures during the grain-filling process. Owing to the disordered starch granule structure, air spaces and low amylose content, chalky grains are easily breakable during milling thereby lowering head rice recovery and its market price. Availability of multiple QTLs associated with grain chalkiness and associated attributes, provided us an opportunity to perform a meta-analysis and identify candidate genes and their alleles contributing to enhanced grain quality.

Arabidopsis plants overexpressing additional copies of heat shock protein Hsp101 showed high heat tolerance and endo-gene silencing.

Hsp101 chaperone is vital for survival of plants under heat stress. We generated transgenic Arabidopsis thaliana (Arabidopsis) lines with extra copies of Hsp101 gene using diverse approaches. Arabidopsis plants transformed with rice Hsp101 cDNA driven by Arabidopsis Hsp101 promoter (IN lines) showed high heat tolerance while the plants transformed with rice Hsp101 cDNA driven by CaMV35S promoter (C lines) were like wild type plants in heat stress response.

Heat-induced proteomic changes in anthers of contrasting rice genotypes under variable stress regimes.

Heat stress drastically affects anther tissues resulting in poor plant fertility, necessitating an urgent need to determine the key proteome regulation associated with mature anther in response to heat stress. We identified several genotype - specific protein alterations in rice anthers of Moroberekan (Japonica, heat sensitive), IR64 (Indica, moderately heat tolerant), and Nagina22 (Aus, heat tolerant) in the short-term (ST_HS; one cycle of 42°C, 4 hours before anthesis) and long-term (LT_HS; 6 cycles of 38°C, 6 hours before anthesis) heat stress. The proteins upregulated in long-term heat stress in Nagina22 were enriched in biological processes related to unfolded protein binding and carboxylic acid metabolism, including amino acid metabolism.

Hsp70, sHsps and ubiquitin proteins modulate HsfA6a-mediated Hsp101 transcript expression in rice (Oryza sativa L.).

Hsp100 chaperones disaggregate the aggregated proteins and are vital for maintenance of protein homeostasis. The level of Hsp100 synthesised in the cells has a bearing on the survival of plants under heat stress. The Hsp100 transcription machinery is activated within minutes of the onset of heat stress.

Tango between Ethylene and HSFA2 Settles Heat Tolerance.

The phytohormone ethylene has roles in senescence, fruit ripening, and biotic and abiotic stress responses. However, the detailed mechanism(s) by which ethylene affects the plant heat stress response (HSR) is not well understood. Two recent studies by Huang et al.

Heat-Induced Oxidation of the Nuclei and Cytosol.

The concept that heat stress (HS) causes a large accumulation of reactive oxygen species (ROS) is widely accepted. However, the intracellular compartmentation of ROS accumulation has been poorly characterized. We therefore used redox-sensitive green fluorescent protein (roGFP2) to provide compartment-specific information on heat-induced redox changes of the nuclei and cytosol of Arabidopsis leaf epidermal and stomatal guard cells.

AtHsc70-1 negatively regulates the basal heat tolerance in Arabidopsis thaliana through affecting the activity of HsfAs and Hsp101.

Heat shock protein 70 (Hsp70) chaperones are highly conserved and essential proteins with diverse cellular functions, including plant abiotic stress tolerance. Hsp70 proteins have been linked with basal heat tolerance in plants. Hsp101 likewise is an important chaperone protein that plays a critical role in heat tolerance in plants.

Silencing of class I small heat shock proteins affects seed-related attributes and thermotolerance in rice seedlings.

Silencing of CI-sHsps by RNAi negatively affected the seed germination process and heat stress response of rice seedlings. Seed size of RNAi was reduced as compared to wild-type plants. Small heat shock proteins (sHsps) are the ATP-independent chaperones ubiquitously expressed in response to diverse environmental and developmental cues.

Cpn60β4 protein regulates growth and developmental cycling and has bearing on flowering time in Arabidopsis thaliana plants.

Chloroplastic Cpn60 proteins are type I chaperonins comprising of Cpn60α and Cpn60β subunits. Arabidopsis genome contains six entries in Cpn60 family, out of which two are for Cpn60α subunit and four for Cpn60β subunit. We noted that the cpn60β4 knockout mutant plants (T-DNA insertion salk_064887 line) differed from the wild type Col-0 plants in the developmental programming.

In vivo promoter engineering in plants: Are we ready?

Engineering plant promoter sequence for optimal expression of a gene has been a long standing goal for plant scientists. In recent times, Sequence Specific Nucleases (SSNs) like CRISPR/Cas9 are enabling researchers to achieve this goal, in vivo in the genome. It is well known that SSNs have met with unprecedented success in rapid transgene free crop improvement largely by targeting the coding sequence.

Mapping of domains of heat stress transcription factor OsHsfA6a responsible for its transactivation activity.

Elevated temperatures affect the growth and reproduction of crop plants and thus have become concern worldwide. Hsp101/ClpB protein is a major molecular chaperone, performing dis-aggregation of protein aggregates formed during heat stress. In rice, OsHsfA6a binds to the promoter of OsHsp101/ClpB-C and regulates its expression.

Analysis of transactivation potential of rice (Oryza sativa L.) heat shock factors.

Based on yeast one-hybrid assays, we show that the presence of C-terminal AHA motifs is not a prerequisite for transactivation potential in rice heat shock factors. Transcriptional activation or transactivation (TA) of heat stress responsive genes takes place by binding of heat shock factors (Hsfs) to heat shock elements. Analysis of TA potential of thirteen rice (Oryza sativa L.

Constitutive over-expression of rice ClpD1 protein enhances tolerance to salt and desiccation stresses in transgenic Arabidopsis plants.

Caseinolytic proteases (Clps) perform the important role of removing protein aggregates from cells, which can otherwise prove to be highly toxic. ClpD system is a two-component protease complex composed of a regulatory ATPase module ClpD and a proteolytic component ClpP. Under desiccation stress condition, rice ClpD1 (OsClpD1) gene encoding for the regulatory subunit, was represented by four variant transcripts differing mainly in the expanse of their N-terminal amino acids.

Expression analysis of ClpB/Hsp100 gene in faba bean (Vicia faba L.) plants in response to heat stress.

Heat stress adversely affects the growth and yield of faba bean crop. Accumulation of ClpB/Hsp100 class of proteins is a critical parameter in induction of acquired heat stress tolerance in plants. Heat-induced expression of ClpB/Hsp100 genes has been noted in diverse plant species.

Characterization of 5'UTR of rice ClpB-C/Hsp100 gene: evidence of its involvement in post-transcriptional regulation.

Rice (Oryza sativa) ClpB-C (OsClpB-C) protein is expressed upon heat stress in vegetative tissues and constitutively in seeds. We produced stably transformed Arabidopsis plants carrying β-glucuronidase (Gus) reporter gene downstream to 1-kb OsClpB-C promoter (1kbPro plants). In the 1kbPro plants, expression of Gus transcript and protein followed the expression pattern of OsClpB-C gene in rice plants, i.

Morphological and physiological characterization of different genotypes of faba bean under heat stress.

Heat stress (HS) is the major constraint to crop productivity worldwide. The objective of the present experiment was to select the tolerant and sensitive genotype(s) on the basis of morpho-physiological and biochemical characteristics of ten Vicia faba genotypes. These genotypes were as follows: Zafar 1, Zafar 2, Shebam 1, Makamora, Espan, Giza Blanka, Giza 3, C4, C5 and G853.

ClpB/Hsp100 proteins and heat stress tolerance in plants.

High-temperature stress can disrupt cellular proteostasis, resulting in the accumulation of insoluble protein aggregates. For survival under stressful conditions, it is important for cells to maintain a pool of native soluble proteins by preventing and/or dissociating these aggregates. Chaperones such as GroEL/GroES (Hsp60/Hsp10) and DnaK/DnaJ/GrpE (Hsp70/Hsp40/nucleotide exchange factor) help cells minimize protein aggregation.

Response of different genotypes of faba bean plant to drought stress.

Drought stress is one of the major abiotic stresses that are a threat to crop production worldwide. Drought stress impairs the plants growth and yield. Therefore, the aim of the present experiment was to select the tolerant genotype/s on the basis of moprpho-physiological and biochemical characteristics of 10 Vicia faba genotypes (Zafar 1, Zafar 2, Shebam, Makamora, Espan, Giza Blanka, Giza 3, C4, C5 and G853) under drought stress.

Constitutive over-expression of rice chymotrypsin protease inhibitor gene OCPI2 results in enhanced growth, salinity and osmotic stress tolerance of the transgenic Arabidopsis plants.

Protease inhibitors are involved primarily in defense against pathogens. In recent years, these proteins have also been widely implicated in response of plants to diverse abiotic stresses. Rice chymotrypsin protease inhibitor gene OCPI2 is highly induced under salt and osmotic stresses.

Current status of the production of high temperature tolerant transgenic crops for cultivation in warmer climates.

Climate change is resulting in heightened incidences of plant heat stress episodes. Production of transgenic crops with enhanced heat stress tolerance is a highly desired agronomic trait for the sustainability of food production in 21st century. We review the current status of our understanding of the high temperature stress response of plants.

Intergenic sequence between Arabidopsis caseinolytic protease B-cytoplasmic/heat shock protein100 and choline kinase genes functions as a heat-inducible bidirectional promoter.

In Arabidopsis (Arabidopsis thaliana), the At1g74310 locus encodes for caseinolytic protease B-cytoplasmic (ClpB-C)/heat shock protein100 protein (AtClpB-C), which is critical for the acquisition of thermotolerance, and At1g74320 encodes for choline kinase (AtCK2) that catalyzes the first reaction in the Kennedy pathway for phosphatidylcholine biosynthesis. Previous work has established that the knockout mutants of these genes display heat-sensitive phenotypes. While analyzing the AtClpB-C promoter and upstream genomic regions in this study, we noted that AtClpB-C and AtCK2 genes are head-to-head oriented on chromosome 1 of the Arabidopsis genome.

Coexpression network analysis associated with call of rice seedlings for encountering heat stress.

Coexpression network analysis is useful tool for identification of functional association of coexpressed genes. We developed a coexpression network of rice from heat stress transcriptome data. Global transcriptome of rice leaf tissues was performed by microarray at three time points--post 10 and 60 min heat stress at 42 °C and 30 min recovery at 26 °C following 60 min 42 °C heat stress to investigate specifically the early events in the heat stress and recovery response.

Generating high temperature tolerant transgenic plants: Achievements and challenges.

Production of plants tolerant to high temperature stress is of immense significance in the light of global warming and climate change. Plant cells respond to high temperature stress by re-programming their genetic machinery for survival and reproduction. High temperature tolerance in transgenic plants has largely been achieved either by over-expressing heat shock protein genes or by altering levels of heat shock factors that regulate expression of heat shock and non-heat shock genes.