Comparison of sudden heat stress with gradual exposure to high temperature during grain filling in two wheat varieties differing in heat tolerance. II. Fractional protein accumulation

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

Two varieties of wheat differing in heat tolerance (cvv. Egret and Oxley, tolerant and sensitive, respectively) were exposed to either a sudden or gradual (6°C h-1) increase from 20 to 40°C to determine if the rate of temperature increase used in controlled-environment studies (1) alters the accumulation of functionally important proteins during grain-filling, and (2) affects the ability to discriminate between heat tolerant and sensitive varieties of wheat. After heat treatment, grain samples were taken throughout grain growth and analysed for protein content and composition. Wheat proteins were separated and quantified as albumin/globulin, monomer, SDS-soluble polymer and SDS-insoluble polymer using size-exclusion high-performance liquid chromatography. The rate of temperature increase exerted a significant influence on the accumulation of total wheat protein and its fractions, and protein fractions differed in their responses to the suddenness of heat stress. The acclimation to heat stress afforded by a gradual increase to high temperature can mitigate the effects of heat stress on fractional protein accumulation, and consequently grain protein composition at maturity. Furthermore, the ability of wheat to acclimate to high temperature varies between genotypes, and this needs to be taken into account when selecting for heat tolerance.

1996 ◽  
Vol 23 (6) ◽  
pp. 739 ◽  
Author(s):  
PJ Stone ◽  
ME Nicolas

Short periods of very high temperature (> 35�C) are common during the grain filling period of wheat, and can significantly alter mature protein composition and consequently grain quality. This study was designed to determine the stage of grain growth at which fractional protein accumulation is most sensitive to a short heat stress, and to examine whether varietal differences in heat tolerance are expressed consistently throughout the grain filling period. Two varieties of wheat differing in heat tolerance (cvv. Egret and Oxley, tolerant and sensitive, respectively) were exposed to a short (5 day) period of very high temperature (40�C max, for 6 h each day) at 5-day intervals throughout grain filling, from 15 to 50 days after anthesis. Grain samples were taken throughout grain growth and analysed for protein content and composition (albumin/globulin, monomer, SDS-soluble polymer and SDS-insoluble polymer) using size-exclusion high-performance liquid chromatography. The timing of heat stress exerted a significant influence on the accumulation of total wheat protein and its fractions, and protein fractions differed in their responses to the timing of heat stress. Furthermore, wheat genotype influenced both the sensitivity of fractional protein accumulation to heat stress and the stage during grain filling at which maximum sensitivity to heat stress occurred.


1996 ◽  
Vol 23 (5) ◽  
pp. 605 ◽  
Author(s):  
PJ Stone ◽  
ME Nicolas ◽  
IF Wardlaw

In this study, we have sought to identify the nature of the response to both moderately high (25-32�C) and very high (>32�C) temperatures by examining their interactive effects on the accumulation of functionally important proteins during grain-filling. In particular, we wished to determine if the deleterious effects of very high temperature could be alleviated by subsequently cool conditions. To this end, wheat cv. Oxley was exposed to either 21/16 or 40/16�C (day/night) from 15 to 19 days after anthesis and subsequently grown under one of three temperature regimes until maturity: 21/16 (control), 27/22 or 30/25�C. Grain samples were taken throughout grain growth and analysed for protein content and composition. Wheat proteins were separated and quantified as albumin,globulin, monomer, SDS-soluble polymer and SDS-insoluble polymer using size-exclusion high-performance liquid chromatography. The various protein fractions responded differentially and usually additively to moderately high and very high temperatures during grain-filling. Cool post-shock conditions did not alleviate the effects of very high temperature on grain protein composition. Heat treatments reduced polymer:monomer ratio because the accumulation of monomer was reduced less than that of polymer.


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.


2010 ◽  
Vol 58 (4) ◽  
pp. 343-353 ◽  
Author(s):  
K. Balla ◽  
M. Rakszegi ◽  
S. Bencze ◽  
I. Karsai ◽  
O. Veisz

Finding and improving wheat cultivars with good adaptability to abiotic stress is an important objective in breeding programmes. An experiment was set up in the climate chamber of the Martonvásár phytotron to test the effect of heat and drought stress on two winter wheat varieties and one variety of durum. Wheat plants exposed to 35°C and drought during grain filling exhibited altered agronomic and grain quality characteristics. Drought was found to have a much greater influence on yield and quality than heat stress. Reductions in the unextractable polymeric protein fraction and the glutenin-to-gliadin ratio indicated poorer grain yield quality as a result of drought, despite higher protein content. Quality deterioration was observed after drought, while heat stress had no noticeable influence on the protein quality of the three wheat genotypes, measured using size exclusion high performance liquid chromatography (SE-HPLC). The durum variety had a better ratio of protein components and a significantly higher Zeleny value when exposed to heat stress, although it had the lowest grain yield and grain/straw ratio.The most significant negative correlation was observed between the Zeleny value and the unextractable polymeric protein (UPP%) fraction after heat treatment and between the relative protein content and the albumin+globulin % (AG%) in the case of drought. These correlations testify that these parameters play an important role in determining the baking quality of wheat flour.


1995 ◽  
Vol 22 (6) ◽  
pp. 935 ◽  
Author(s):  
PJ Stone ◽  
ME Nicolas

Two wheat varieties differing in heat tolerance were exposed to four heat treatments in order to determine if a sudden rise from ca 20-40�C caused a greater reduction of individual kernel mass than a gradual (6�C h-1) rise over the same temperature range. For the heat sensitive variety (Oxley), the reduction of individual kernel mass following sudden heat stress (26%) was greater than that resulting from a gradual heat stress of equivalent thermal time (13%) or equal days of treatment (18%). By contrast, for the heat tolerant variety (Egret), the reduction of individual kernel mass following rapid exposure to heat stress (12%) was not significantly greater than that caused by a gradual treatment of equal days duration (10%). Nevertheless, for Egret, sudden heat stress significantly reduced mature kernel mass compared with high temperature treatment of equivalent thermal time (6%). We conclude that heat acclimation may help to mitigate wheat yield losses due to high temperature and that the ability to acclimate to high temperature varies between wheat genotypes. Comparison of wheat varieties for yield tolerance to high temperature should therefore occur under conditions that allow gradual acclimation to elevated temperature.


1996 ◽  
Vol 23 (6) ◽  
pp. 727 ◽  
Author(s):  
PJ Stone ◽  
ME Nicolas

Two varieties of wheat differing in high-molecular-weight glutenin subunit composition (Oxley, 2+12, Glu-D1a and Egret, 5+10, Glu-D1d) and dough properties were examined in order to determine the manner in which differences in mature protein composition were the result of differences in accumulation of proteins during grain filling. To this end, grain samples from each cultivar were taken at 5 day intervals from 10 days after anthesis to maturity, and analysed for protein content and composition. Wheat proteins were separated and quantified as albumin/globulin, monomer, SDS-soluble polymer and SDS-insoluble polymer using size-exclusion high-performance liquid chromatography. For both cultivars, the accumulation of each class of protein was found to be highly asynchronous: synthesis of albumin/globulin was followed by that of monomer, SDS-soluble polymer and finally SDS-insoluble polymer, such that the average molecular size of grain protein increased throughout grain filling. Varietal differences in mature protein composition were almost entirely the result of a greater rate of polymer accumulation in the 2+12 than in the 5+10 genotype.


2015 ◽  
Vol 75 (1) ◽  
pp. 121
Author(s):  
W. F. Song ◽  
L. J. Zhao ◽  
X. M. Zhang ◽  
Y. M. Zhang ◽  
J. L. Li ◽  
...  

1995 ◽  
Vol 22 (6) ◽  
pp. 927 ◽  
Author(s):  
PJ Stone ◽  
ME Nicolas

Short periods of very high temperature (> 35�C) are common in many of the world's wheat growing areas and can be a significant factor in reducing yield and quality of wheat. This study was designed to determine the stage at which grain growth is most sensitive to a short period of high temperature and to examine whether varietal differences in heat tolerance are expressed throughout the whole grain-filling period. Two varieties of wheat differing in heat tolerance (cvv. Egret and Oxley) were exposed to a short (5 days) period of very high temperature (40�C max. for 6 h each day) at 5-day intervals throughout grain filling, starting from 15 days after anthesis (DAA) and concluding at 50 DAA. Responses of grain dry matter accumulation and water content to high temperature were monitored throughout grain filling, and the results compared with controls maintained at 21/16�C day/night. Varietal differences in heat tolerance were expressed throughout the grain-filling period. Mature individual kernel mass was most sensitive to heat stress applied early in grain filling and became progressively less sensitive throughout grain filling, for both varieties. Reductions in mature kernel mass resulted primarily from reductions in duration rather than rate of grain filling.


Plants ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 687
Author(s):  
Chan Seop Ko ◽  
Jin-Baek Kim ◽  
Min Jeong Hong ◽  
Yong Weon Seo

High-temperature stress during the grain filling stage has a deleterious effect on grain yield and end-use quality. Plants undergo various transcriptional events of protein complexity as defensive responses to various stressors. The “Keumgang” wheat cultivar was subjected to high-temperature stress for 6 and 10 days beginning 9 days after anthesis, then two-dimensional gel electrophoresis (2DE) and peptide analyses were performed. Spots showing decreased contents in stressed plants were shown to have strong similarities with a high-molecular glutenin gene, TraesCS1D02G317301 (TaHMW1D). QRT-PCR results confirmed that TaHMW1D was expressed in its full form and in the form of four different transcript variants. These events always occurred between repetitive regions at specific deletion sites (5′-CAA (Glutamine) GG/TG (Glycine) or (Valine)-3′, 5′-GGG (Glycine) CAA (Glutamine) -3′) in an exonic region. Heat stress led to a significant increase in the expression of the transcript variants. This was most evident in the distal parts of the spike. Considering the importance of high-molecular weight glutenin subunits of seed storage proteins, stressed plants might choose shorter polypeptides while retaining glutenin function, thus maintaining the expression of glutenin motifs and conserved sites.


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.


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