scholarly journals Involvement of Ca2+ in Regulation of Physiological Indices and Heat Shock Factor Expression in Four Iris germanica Cultivars under High-temperature Stress

2014 ◽  
Vol 139 (6) ◽  
pp. 687-698 ◽  
Author(s):  
Jing Mao ◽  
Hongliang Xu ◽  
Caixia Guo ◽  
Jun Tong ◽  
Yanfang Dong ◽  
...  

Although tolerance to high temperature is crucial to the summer survival of Iris germanica cultivars in subtropical areas, few physiological studies have been conducted on this topic previously. To remedy this, this study explored the physiological response and expression of heat shock factor in four I. germanica cultivars with varying levels of thermotolerance. The plants’ respective degrees of high-temperature tolerance were evaluated by measuring the ratio and area of withered leaves under stress. Several physiological responses to high temperatures were investigated, including effects on chlorophyll, antioxidant enzymes, proline, and soluble protein content in the leaves of four cultivars. CaCl2 was sprayed on ‘Gold Boy’ and ‘Royal Crusades’ considered being sensitive to high temperatures to study if Ca2+ could improve the tolerance, and LaCl3 was sprayed on ‘Music Box’ and ‘Galamadrid’ with better high-temperature tolerance to test if calcium ion blocker could decrease their tolerance. Heat shock factor genes were partially cloned according to the conserved region sequence, and expression changes to high-temperature stress with CaCl2 or LaCl3 treatments were thoroughly analyzed. Results showed that high temperature is the primary reason for large areas of leaf withering. The ratio and area of withered leaves on ‘Music Box’ and ‘Galamadrid’ were smaller than ‘Gold Boy’ and ‘Royal Crusades’. CaCl2 slowed the degradation of chlorophyll content and increased proline and soluble protein in ‘Gold Boy’ and ‘Royal Crusades’ but had no significant effect on activating peroxidase or superoxide to improve high-temperature tolerance. Genetic expression of heat shock factor in ‘Gold Boy’ and ‘Royal Crusades’ was upregulated by Ca2+ at later stages of leaf damage under high-temperature stress. LaCl3 down-regulated the physiological parameters and expression level of heat shock factor in ‘Music Box’ and ‘Galamadrid’. These results suggest that different I. germanica cultivars have varying high-temperature tolerance and furthermore that Ca2+ regulates their physiological indicators and expression level of heat shock factor under stress.

Author(s):  
Jing Chang ◽  
Jianzhi Shi ◽  
Jianzhang Lin ◽  
Dehua Ji ◽  
Yan Xu ◽  
...  

AbstractGlobal warming is one of the key limiting factors affecting the cultivation of Pyropia haitanensis which is an economically important macroalgae species grown in southern China. However, the mechanism underlying the high-temperature tolerance of P. haitanensis remains largely unknown. In a previous study, we showed that the expression of the small heat shock protein 22 gene (Hsp22) is upregulated in P. haitanensis in response to high-temperature stress, but the associated regulatory mechanism was not fully elucidated. In this study, a transgenic Chlamydomonas reinhardtii expression system was used to functionally characterize P. haitanensis Hsp22. Our analyses indicated that the C-terminal of PhHsp22 is highly conserved and contains an A-crystal structure domain. A phylogenetic analysis revealed PhHsp22 is not closely related to small heat shock protein genes in other species. Additionally, PhHsp22 expression significantly increased at 3 and 6 h after initiating 33 °C treatment, which improved the survival rate of transgenic C. reinhardtii during the early stage of high-temperature treatment. The further transcriptome analysis revealed that PhHsp22 expression can promote pathways related to energy metabolism, metabolites metabolism, and protein homeostasis in transgenic C. reinhardtii cells exposed to high temperatures. Therefore, PhHsp22 may be crucial for the response of Pyropia species to high-temperature stress. Furthermore, this gene may be useful for breeding new high-temperature algal strains.


2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Yufang Xu ◽  
Li Zhang ◽  
Shujun Ou ◽  
Ruci Wang ◽  
Yueming Wang ◽  
...  

Abstract With global warming and climate change, breeding crop plants tolerant to high-temperature stress is of immense significance. tRNA 2-thiolation is a highly conserved form of tRNA modification among living organisms. Here, we report the identification of SLG1 (Slender Guy 1), which encodes the cytosolic tRNA 2-thiolation protein 2 (RCTU2) in rice. SLG1 plays a key role in the response of rice plants to high-temperature stress at both seedling and reproductive stages. Dysfunction of SLG1 results in plants with thermosensitive phenotype, while overexpression of SLG1 enhances the tolerance of plants to high temperature. SLG1 is differentiated between the two Asian cultivated rice subspecies, indica and japonica, and the variations at both promoter and coding regions lead to an increased level of thiolated tRNA and enhanced thermotolerance of indica rice varieties. Our results demonstrate that the allelic differentiation of SLG1 confers indica rice to high-temperature tolerance, and tRNA thiolation pathway might be a potential target in the next generation rice breeding for the warming globe.


2019 ◽  
Vol 56 (4) ◽  
pp. 341-351
Author(s):  
Veronica N ◽  
Ashoka Rani Y ◽  
Subrahmanyam D ◽  
Narasimha Rao KL ◽  
Lal Ahamad M ◽  
...  

High temperature during the crop growing period is detrimental as it results in reduction of yield. A diverse set of rice germplasm consisting of 60 genotypes was grown at two different sowing times (normal and late) and were exposed naturally to high temperature in the late sown condition (stress). There was a severe reduction in grain yield and spikelet fertility in all the genotypes in the late sown crop. Yield based indices were computed based on grain yield recorded under normal and stress conditions. Indices Stress Susceptibility Index (STI), Geometric Mean Production (GMP), Mean Production (MP), Yield Index (YI), Modified stress tolerance (K1STI and K2STI) were positively correlated with yield recorded under both normal and high temperature stress condition and can be considered as suitable indices for screening of rice genotypes under high temperature conditions. Ranking genotypes based on the indices revealed that Rasi, HKR47, IR64, Khudaridhan, Akshayadhan and N22 exhibited the highest mean rank and hence they can be identified as heat-tolerant genotypes. ADT43, Vandana, IR36, MTU1001, ADT49 and Krishnahamsa had a lower rank and were identified as susceptible genotypes to high-temperature stress.


Author(s):  
Uwimana Marie Ange ◽  
S. Srividhya ◽  
C. Vijayalakshmi ◽  
P. Boominathan

The responses of soybean genotypes to high temperature for intrinsic tolerance was studied using Temperature Induction Response (TIR) technique in order identify the genotypes tolerant to high temperature stress. Seven soybean genotypes subjected to lethal and sub lethal temperatures showed significant variation for acquired thermotolerance. Thermotolerant genotypes ADT 1 and CoSoy1 identified by the TIR technique, demonstrated higher survival percentage, and lower growth reduction. Further the tolerant genotypes identified based on TIR also showed higher antioxidant enzymes activity implying the critical role of antioxidant in cellular thermotolerance. This clearly demonstrated that TIR can be effectively used for screening high temperature tolerance genotypes in soybean. This study also established the fact that the alternations in antioxidants during induction are vital for imparting tolerance to high temperature stress.


Author(s):  
Amjad Farooq ◽  
Amir Shakeel ◽  
Waqas Shafqat Chattha ◽  
Tariq Manzoor Khan ◽  
Muhammad Tehseen Azhar ◽  
...  

Abstract High temperature negatively affects cotton production worldwide. In Pakistan, cotton crop faces high temperature at peak flowering during June–July, which is a major reason for yield losses. The present study was conducted to find some agro-physiological markers for high-temperature tolerance. Fifty cotton genotypes were raised under normal sown (high-temperature stress) and late sown (optimum temperature) conditions for 2 years. Data were recorded for relative cell injury percentage (RCI), chlorophyll content (CC), canopy temperature (CT), boll retention percentage (BR), bolls per plant (BP), boll weight (BW), hundred seed weight (HSW), sympodial branches per plant (SBP), plant height (PH) and seed cotton yield (SCY). A large amount of variability was found among cotton genotypes as proved by descriptive statistics. Stable genotypes were selected based on higher SCY and yield components (BP, BW, HSW, SBP, PH and SCY) performance along with less RCI%, high CC and low CT. The results of heatmap analysis showed that the six cotton genotypes viz., FH-Noor, FH-Lalazar, FH-458, FH-466, NIAB-545 and NIAB-878 performed better under high-temperature stress. These selected genotypes can be a source for breeding high-temperature tolerance. Furthermore, the results from correlation analysis confirmed that the traits such as RCI%, CC and CT can be considered as early selection criteria due to their positive association with SCY. Whilst some other parameters such as BP, BW, BR, SBP and PH might be used as direct selection indices for SCY under high-temperature stress.


Genetika ◽  
2020 ◽  
Vol 52 (3) ◽  
pp. 1107-1125
Author(s):  
Mohamed Barakat ◽  
Abdullah Al-Doss ◽  
Khaled Moustafa ◽  
Mohamed Motawei ◽  
Ibrahim Al-Ashkar ◽  
...  

Stress induced by high temperature represents a major constraint over wheat production in many production areas. Here, the comprehensive coverage of the wheat genome achievable using single nucleotide polymorphism markers was exploited to carry out a genetic analysis targeting yield components in plants exposed to high temperature stress. The mapping population was a set of doubled haploid lines derived from a cross between the cultivars Yecora Rojo and Ksu106. Both of the parental cultivars and their derived population were tested in the field in two locations over two consecutive seasons; at each site, two sowing dates were included, with the later sowing intended to ensure that the plants were exposed to high temperature stress during the grain filling period. Composite interval mapping detected 93 quantitative trait loci influencing grain yield and some related traits, along with 20 loci associated with a ?heat susceptibility index? (HSI). The loci were distributed over all 21 of the wheat chromosomes. Some of these loci were of large enough effect to be considered as candidates for the marker-assisted breeding of high temperature tolerance in wheat.


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