scholarly journals Development of an in vitro Microtuberization and Temporary Immersion Bioreactor System to Evaluate Heat Stress Tolerance in Potatoes (Solanum tuberosum L.)

2021 ◽  
Vol 12 ◽  
Author(s):  
Sanjeev Gautam ◽  
Nora Solis-Gracia ◽  
Megan K. Teale ◽  
Kranthi Mandadi ◽  
Jorge A. da Silva ◽  
...  

High temperature (heat) stress reduces tuber yield and quality of potatoes. Screening potatoes for heat tolerance is increasingly important, considering the climate change scenario and expansion of potatoes to countries where heat stress is an issue. In vitro screening for tolerance to abiotic stresses offers several advantages, including quick evaluation of numerous genotypes (clones) in reduced space, controlled environmental conditions (temperature and photoperiod), and free from confounding variables inherent to greenhouse and field conditions. In this study, we explored the feasibility of using a temporary immersion bioreactor system for heat tolerance screening of potatoes. We determined the best hormone-free microtuberizing media for this system (MSG with 8% sucrose) to enhance microtuber number and size. Comparisons of microtubers produced at 30°C as heat treatment, with 16°C as normal condition, allowed to identify heat tolerant and susceptible potato clones. The use of bioreactors allowed distinguishing well-formed (non-deformed) from deformed microtubers. Heat stress increased the total biomass of plant tissues in all the clones. However, the effect of heat stress on microtuber number and weight varied among the clones. Incubation at 30°C decreased the weight and number of non-deformed microtubers in all the clones except for Reveille Russet in which the weight of non-deformed microtubers was significantly increased and the count of non-deformed microtubers was not affected. The potato variety Reveille Russet, which was selected under high-temperature field conditions in Texas, had many non-deformed microtubers per explant and the highest microtuber weight among four clones evaluated under heat stress. We described a faster and reliable in vitro microtuberization system for abiotic stress tolerance screening, identified Reveille Russet as a promising heat-tolerant potato variety, and confirmed Russet Burbank and Atlantic as susceptible heat-tolerant checks.

Author(s):  
Sherzod Nigmatullayevich Rajametov ◽  
Eun Young Yang ◽  
Hyo Bong Jeong ◽  
Myeong Cheoul Cho ◽  
Soo-Young Chae ◽  
...  

High temperature seriously effects on plant vegetative and reproductive development and reduces productivity of plants, while to increase crop yield is the main target in most crop heat stress tolerance improvement breeding programs, not just survival, under high temperature. Our aim was to compare temperature stress tolerance in two commercial tomato cultivars “Dafnis” (big fruit size) and “Minichal” (cherry fruit size) to develop early screening methods and find out survival rate and physiological responses of tomato cultivars on high temperature (40°C and within 70% RH, day/night) in 4-5 true leaf seedling stage- (4LS) and identifies the linkage of heat tolerance with fruit set and leaf heat damage rates (LHD) in seedling stage with subsequent vegetative traits at recovery. Results showed that heat stress significantly affected on physiological-chemical and vegetative parameters of seedlings regardless of tomato cultivars. Survival and the threshold level of high temperature tolerance in the seedlings of cv. “Dafnis” and “Minichal” were identified on days 7 and 9, respectively. Our findings revealed that photosynthesis (PN, Gs, Ci, Tr) parameters were increased and CHL content persisted steady value in cv. “Minichal” during heat stress period, however EC and RPL rates were lower than cv. “Dafnis”. Heat stress reduced the SFW in both cultivars in seedling stage, but PH and RFW were significantly decreased in the heat tolerant cv. “Minichal”, whereas this parameters were not significantly ranged in the heat susceptible cv. “Dafnis”. Additionally, there no found linkage between vegetative parameters with decreasing of PN and CHL rates during HT of seedlings. In plants of cv. “Minichal” with LHD-25, 50 and 75% were no found significant differences in PH, whereas in cv. “Dafnis” significant differences were determined in plants with LHD-75%, and the significant differences in rates of SFW and RFW were observed in plants of cv. “Dafnis” having LHD-75% for 28 days of recovery at NT condition. Taken together, we concluded that heat stress affected on physiological parameters regardless of tolerance level, and to identify heat tolerant genotype in tomato breeding program, screening and selection genotypes have to be evaluated at the vegetative and reproductive stages with consideration fruit size types. Since we could not find linkage between heat tolerances in seedling stage with fruit set at the reproductive stage and fruit set cannot be used as a general predictor of heat tolerance.


2020 ◽  
Vol 47 (5) ◽  
pp. 440 ◽  
Author(s):  
Syed Adeel Zafar ◽  
Amjad Hameed ◽  
Muhammad Ashraf ◽  
Abdus Salam Khan ◽  
Zia-ul- Qamar ◽  
...  

Climatic variations have increased the occurrence of heat stress during critical growth stages, which negatively affects grain yield in rice. Plants adapt to harsh environments, and particularly high-temperature stress, by regulating their physiological and biochemical processes, which are key tolerance mechanisms. The identification of heat-tolerant rice genotypes and reliable selection indices are crucial for rice improvement programs. Here, we evaluated the response of a rice mutant population for high-temperature stress at the seedling and reproductive stages based on agronomic, physiological and molecular indices. Estimates of variance components revealed significant differences (P < 0.001) among genotypes, treatments and their interactions for almost all traits. The principal component analysis showed significant diversity among genotypes and traits under high-temperature stress. The mutant HTT-121 was identified as the most heat-tolerant mutant with higher grain yield, panicle fertility, cell membrane thermo-stability (CMTS) and antioxidant enzyme levels under heat stress. Various seedling-based morpho-physiological traits (leaf fresh weight, relative water contents, malondialdehyde, CMTS) and biochemical traits (superoxide dismutase, catalase and hydrogen peroxide) explained variations in grain yield that could be used as selection indices for heat tolerance in rice during early growth. Notably, heat-sensitive mutants accumulated reactive oxygen species, reduced catalase activity and upregulated OsSRFP1 expression under heat stress, suggesting their key roles in regulating heat tolerance in rice. The heat-tolerant mutants identified in this study could be used in breeding programs and to develop mapping populations to unravel the underlying genetic architecture for heat-stress adaptability.


1994 ◽  
Vol 21 (6) ◽  
pp. 857 ◽  
Author(s):  
HT Nguyen ◽  
CP Joshi ◽  
N Klueva ◽  
J Weng ◽  
KL Hendershot ◽  
...  

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.


2007 ◽  
Vol 132 (2) ◽  
pp. 185-192 ◽  
Author(s):  
Yan Xu ◽  
Bingru Huang

Leaf senescence can be induced by many environmental stresses, including supraoptimal temperatures. The objectives of this study were to evaluate leaf senescence induced by heat stress for two Agrostis species contrasting in heat tolerance and to examine whether heat-induced leaf senescence in both species was associated with changes in three major senescence-related hormones: ethylene, abscisic acid (ABA), and cytokinins. Plants of heat-tolerant rough bentgrass (Agrostis scabra Willd.) and heat-sensitive creeping bentgrass (Agrostis stolonifera L.) were exposed to 35/30 °C (day/night) (high temperature) or 20/15 °C (control) for 35 d in growth chambers. Turf quality, photochemical efficiency (Fv/Fm), and the contents of two pigments (chlorophyll and carotenoid) for both species decreased under high temperature; however, heat-tolerant A. scabra exhibited delayed and less severe decline in all parameters compared with heat-sensitive A. stolonifera. Ethylene production rate increased in both species at 35 °C, but the increase was observed 21 days later in A. scabra compared with that in A. stolonifera. ABA content increased at the initiation of heat stress and then declined in both species after prolonged heat stress. However, the timing of the increase was delayed for 7 days and the highest level of ABA content was less in A. scabra (4.0 times that of the control) than that in A. stolonifera (5.9 times that of the control). Decreases in both forms of cytokinins (transzeatin/zeatin riboside and isopentenyl adenosine) were also delayed for 14 days and less pronounced in A. scabra. Correlation analysis revealed that leaf senescence induced by heat stress was negatively correlated to ethylene and ABA accumulation and positively correlated to cytokinin production. Delayed leaf senescence in A. scabra under heat stress could be related to slower and less magnitude of changes in ethylene, ABA, and cytokinins.


2019 ◽  
Vol 85 (16) ◽  
Author(s):  
Andrea J. Etter ◽  
Alyssa M. West ◽  
John L. Burnett ◽  
Sophie Tongyu Wu ◽  
Deklin R. Veenhuizen ◽  
...  

ABSTRACTSalmonella entericaserovar Heidelberg is currently the 12th most common serovar ofSalmonella entericacausing salmonellosis in the United States and results in twice the average incidence of blood infections caused by nontyphoidal salmonellae. Multiple outbreaks of salmonellosis caused bySalmonellaHeidelberg resulted from the same poultry processor, which infected 634 people during 2013 and 2014. The hospitalization and invasive illness rates were 38% and 15%, respectively. We hypothesized that the outbreak strains ofSalmonellaHeidelberg had enhanced stress tolerance and virulence capabilities. We sourced nine food isolates collected during the outbreak investigation and three reference isolates to assess their tolerance to heat and sanitizers, ability to attach to abiotic surfaces, and invasivenessin vitro. We performed RNA sequencing on three isolates (two outbreak-associated isolates and a referenceSalmonellaHeidelberg strain) with various levels of heat tolerance to gain insight into the mechanism behind the isolates’ enhanced heat tolerance. We also performed genomic analyses to determine the genetic relationships among the outbreak isolates. Ultimately, we determined that (i) sixSalmonellaHeidelberg isolates associated with the foodborne outbreak had enhanced heat tolerance, (ii) one outbreak isolate with enhanced heat tolerance also had an enhanced biofilm-forming ability under stressful conditions, (iii) exposure to heat stress increased the expression ofSalmonellaHeidelberg multidrug efflux and virulence genes, and (iv) outbreak-associated isolates were likely transcriptionally primed to better survive processing stresses and, potentially, to cause illness.IMPORTANCEThis study provides a deep analysis of the intrinsic stress tolerance and virulence capabilities ofSalmonellaHeidelberg that may have contributed to the length and severity of a recent salmonellosis outbreak. Additionally, this study provides a comprehensive analysis of the transcriptomic response ofS. entericastrains to heat stress conditions and compares baseline stationary-phase gene expression among outbreak- and non-outbreak-associatedSalmonellaHeidelberg isolates. These data can be used in assay development to screen isolates for stress tolerance and subsequent survival. This study adds to our understanding of the strains associated with the outbreak and informs ongoing regulatory discussions onSalmonellain poultry.


1970 ◽  
Vol 40 (1) ◽  
pp. 17-22 ◽  
Author(s):  
JU Ahmed ◽  
MA Hassan

Seedling of 20 wheat genotypes were grown in Phytotron at about 25 and 35°C for measuring membrane injury in per cent and seedling proline content to investigate seedling proline as screening criterion against heat stress. The wheat genotypes (Bijoy, Sufi, Kanchan, Fang 60, BAW 1059, BL 1883, BL 1022, IVT 7, IVT 8, IVT 9, IVT 10 and BAW 917) showing < 50% membrane injury were grouped as heat tolerant (HT) and the genotypes (Shatabdi, Prodip, BAW 1064, Gourab, Pavon 76, Sonora, Kalyansona and IVT 6) showing ≥ 50% membrane injury were classified as heat sensitive (HS). At high temperature (35°C) the HT genotypes produced more than double (> 200%) proline than that of 25°C but the HS genotypes produced less quantity of proline at 35°C compared to that in HT genotypes. The seedling proline content at 35°C and membrane injury (%) maintained a significant negative correlation (r = – 0.619**) across the 20 wheat genotypes tested. Key words: Membrane thermostability; Seedling proline; Heat tolerance; Wheat DOI: http://dx.doi.org/10.3329/bjb.v40i1.7991 Bangladesh J. Bot. 40(1): 17-22, 2011 (June)


2012 ◽  
Vol 64 (1) ◽  
pp. 135-144 ◽  
Author(s):  
Jelena Savic ◽  
Ivana Dragicevic ◽  
D. Pantelic ◽  
Jasmina Oljaca ◽  
Ivana Momcilovic

We have examined the correlation between heat tolerance and small heat shock protein (sHSP) expression under heat stress conditions in potato (Solanum tuberosum L.). The relative heat tolerance of nine potato cultivars grown under greenhouse conditions was determined using the electrolyte leakage assay (ELA), a standard quantitative assay for heat tolerance. Three cultivars differing in heat tolerance were selected and designated as heat-tolerant (?Laura?), moderately sensitive (?Liseta?) and heat-sensitive (?Agria?) genotypes. The expression of cytosolic HSP18 and chloroplast HSP21 was analyzed at the protein level in the leaves of selected cultivars, both ex vitro- and in vitro-grown, after heat stress or control treatment. Immunoblot analysis revealed heat-induced HSP18 and HSP21 expression in all examined genotypes. A similar pattern of examined sHSP expression was observed ex vitro and in vitro: heat-tolerant ?Laura? accumulated higher levels of both HSP18 and HSP21 compared to heat-sensitive ?Liseta? and ?Agria?. Our results indicate that ELA combined with immunoblot analysis of sHSP accumulation under HS conditions, might be considered as a reliable procedure in screening potato genotypes for heat tolerance. To our knowledge, this is the first study where sHSP expression between ex vitro- and in vitro-grown potato plants was compared.


2021 ◽  
Vol 11 ◽  
Author(s):  
Lei Chen ◽  
Qiang Wang ◽  
Maoyan Tang ◽  
Xiaoli Zhang ◽  
Yinghua Pan ◽  
...  

High-temperature stress can cause serious abiotic damage that limits the yield and quality of rice. Heat tolerance (HT) during the flowering stage of rice is a key trait that can guarantee a high and stable yield under heat stress. HT is a complex trait that is regulated by multiple quantitative trait loci (QTLs); however, few underlying genes have been fine mapped and cloned. In this study, the F2:3 population derived from a cross between Huanghuazhan (HHZ), a heat-tolerant cultivar, and 9311, a heat-sensitive variety, was used to map HT QTLs during the flowering stage in rice. A new major QTL, qHTT8, controlling HT was identified on chromosome 8 using the bulked-segregant analysis (BSA)-seq method. The QTL qHTT8 was mapped into the 3,555,000–4,520,000 bp, which had a size of 0.965 Mb. The candidate region of qHTT8 on chromosome 8 contained 65 predicted genes, and 10 putative predicted genes were found to be associated with abiotic stress tolerance. Furthermore, qRT-PCR was performed to analyze the differential expression of these 10 genes between HHZ and 9311 under high temperature conditions. LOC_Os08g07010 and LOC_Os08g07440 were highly induced in HHZ compared with 9311 under heat stress. Orthologous genes of LOC_Os08g07010 and LOC_Os08g07440 in plants played a role in abiotic stress, suggesting that they may be the candidate genes of qHTT8. Generally, the results of this study will prove useful for future efforts to clone qHTT8 and breed heat-tolerant varieties of rice using marker-assisted selection.


HortScience ◽  
2019 ◽  
Vol 54 (9) ◽  
pp. 1470-1476 ◽  
Author(s):  
Adam Bolton ◽  
Aneela Nijabat ◽  
Muhammad Mahmood-ur-Rehman ◽  
Naima Huma Naveed ◽  
A.T.M. Majharul Mannan ◽  
...  

Carrot production is constrained by high levels of heat stress during the germination stage in many global regions. Few studies have been published evaluating the effect of heat stress on carrot seed germination or screening for genetic heat stress tolerance. The objectives of this study were to evaluate the response of diverse carrot germplasm to heat stress, identify heat-tolerant germplasm that may be used by plant breeders, and define the appropriate temperature for assessing heat tolerance in germinating carrot seed. To identify an appropriate screening temperature, three commercial hybrids and an open pollinated variety were evaluated at five temperatures (24, 32.5, 35, 37.5, and 40 °C). In preliminary studies, 35 °C was identified as the optimal temperature for screening heat tolerance of carrot seed. Cultivated and wild carrot plant introductions (PIs) (n = 270) from the U.S. Department of Agriculture (USDA) National Plant Germplasm System (NPGS) representing 41 countries, inbred lines from the USDA Agricultural Research Service (n = 15), and widely grown commercial hybrids (n = 8) were evaluated for heat tolerance under heat stress and nonstress conditions (35 °C and 24 °C, respectively) by calculating absolute decrease in percent germination (AD), inhibition index (II), relative heat tolerance (RHT), and heat tolerance index (HTI). All measurements of heat tolerance identified significant differences among accessions; AD ranged from −13.0% to 86.7%, II ranged from 35.7% to 100.0%, RHT ranged from 0 to 1.36, and HTI ranged from 0.0 to 1.45. The broad-sense heritability (H2) calculations ranged from 0.64 to 0.86 for different traits, indicating a moderately strong genetic contribution to the phenotypic variation. Several wild carrot accessions and inbred lines displayed low levels of heat tolerance, whereas cultivated accessions PI 643114 (United States), PI 652400 and PI 652403 (Turkey), PI 652208 (China), and PI 652403 (Russia) were most heat tolerant. This is the first evaluation of heritability for heat stress tolerance during carrot seed germination, the first measure of HTI, and the first correlation calculation between heat and salt tolerance during germination in carrot.


1998 ◽  
Vol 25 (1) ◽  
pp. 13 ◽  
Author(s):  
P.J. Stone ◽  
M.E. Nicolas

Two varieties of wheat differing in heat tolerance were exposed to very high temperature (40/19°C day/night) for periods of 1–10 days duration. Responses of grain dry matter, water and fractional protein accumulation to high temperature were monitored throughout grain filling in the heat- sensitive variety, and at maturity only in the heat-tolerant variety. Results are compared with controls maintained at 21/16°C day/night. As little as 1 day of heat treatment reduced kernel mass by 14% in the heat-sensitive variety (Oxley), but by only 5% in the heat-tolerant variety (Egret). In both varieties, the reduction of individual kernel mass due to high temperature increased linearly with increased duration of heat treatment, such that after the first day of heat stress, each additional day of treatment reduced mature individual kernel mass by a further 1.6%. For a given duration of heat treatment, the difference in response of the two varieties was constant (9%), indicating that the varietal difference in heat tolerance was maintained for both brief and extended periods of very high temperature. Responses of grain water content and fractional protein accumulation to duration of heat stress are discussed.


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