scholarly journals Characterization of physicochemical qualities and starch structures of two indica rice varieties tolerant to high temperature during grain filling

2020 ◽  
Vol 93 ◽  
pp. 102966 ◽  
Author(s):  
Xiaolei Fan ◽  
Yingqiu Li ◽  
Yun Zhu ◽  
Jingdong Wang ◽  
Jie Zhao ◽  
...  
2017 ◽  
Vol 42 (1) ◽  
pp. 53-65
Author(s):  
Mohammed Humayun Kabir ◽  
Qing Liu ◽  
Yi Su ◽  
Zhigang Huang ◽  
Langtao Xiao

A pot experiment on an early indica rice cv. ‘Shenyou9576’ was conducted in the net house of Hunan Agricultural University, Changsha, Hunan, PR China during the early growing season of 2013 to investigate the influence of varying temperatures on chalkiness rate, head rice rate, and phytohormones, namely indole-3-acetic acid (IAA), gibberellins (GA1 and GA4), zeatin (Z), zeatin riboside (ZR) and abscisic acid (ABA) both in flag leaves and grain endosperm during grain filling period. The treatments comprised three temperature regimes which are designated as the high (35/28oC- day/night), low (25/20oC- day/night) and natural condition as the control (35/25oC- day/night). The results showed that the maximum chalkiness rate was 61.11% under high temperature and the minimum (22.59%) under low temperature. The lowest head rice rate was 42.76% under high temperature followed by 49.91% in the control, while the highest (62.33%) under low temperature. The contents of GA1, GA4, Z and ZR were decreased gradually from 7 to 35 days after anthesis (DAA) irrespective of treatments. IAA content began to decrease from 14 DAA and continued up to 35 DAA and ABA was reduced from 28 to 35 DAA under low temperature in comparison to control and high temperature. ABA content was increased from 7 to 21 DAA and then declined at high temperature. The results showed that contents of GA1, GA4, Z, ZR were high at low temperature compared to high temperature and control. IAA content was also high during grain development period at low temperature except 7 DAA. Higher phytohormone contents were observed in endosperm than in flag leaves. Phytohormone content ratio (endosperm: flag leaves) was found highest in IAA and the lowest in GA1. A significant positive correlation was found between ABA and chalkiness rate during early to mid grain filling period, while significant negative correlations were noticed between chalkiness rate and other phytohormones during grain filling period. Correlation results revealed that increased level of ABA during early to mid grain filing period caused by high temperature was more responsible for development of chalkiness.Bangladesh J. Agril. Res. 42(1): 53-65, March 2017


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.


2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Jae-Ryoung Park ◽  
Eun-Gyeong Kim ◽  
Yoon-Hee Jang ◽  
Kyung-Min Kim

Abstract Background Recent temperature increases due to rapid climate change have negatively affected rice yield and grain quality. Particularly, high temperatures during right after the flowering stage reduce spikelet fertility, while interfering with sugar energy transport, and cause severe damage to grain quality by forming chalkiness grains. The effect of high-temperature on spikelet fertility and grain quality during grain filling stage was evaluated using a double haploid line derived from another culture of F1 by crossing Cheongcheong and Nagdong cultivars. Quantitative trait locus (QTL) mapping identifies candidate genes significantly associated with spikelet fertility and grain quality at high temperatures. Results Our analysis screened OsSFq3 that contributes to spikelet fertility and grain quality at high-temperature. OsSFq3 was fine-mapped in the region RM15749-RM15689 on chromosome 3, wherein four candidate genes related to the synthesis and decomposition of amylose, a starch component, were predicted. Four major candidate genes, including OsSFq3, and 10 different genes involved in the synthesis and decomposition of amylose and amylopectin, which are starch constituents, together with relative expression levels were analyzed. OsSFq3 was highly expressed during the initial stage of high-temperature treatment. It exhibited high homology with FLOURY ENDOSPERM 6 in Gramineae plants and is therefore expected to function similarly. Conclusion The QTL, major candidate genes, and OsSFq3 identified herein could be effectively used in breeding rice varieties to improve grain quality, while tolerating high temperatures, to cope with climate changes. Furthermore, linked markers can aid in marker-assisted selection of high-quality and -yield rice varieties tolerant to high temperatures.


2019 ◽  
Vol 44 (2) ◽  
pp. 223-238
Author(s):  
Mohammed Humayun Kabir ◽  
Qing Liu ◽  
Shitou Xia ◽  
Ruozhong Wang ◽  
Langtao Xiao

An experiment on an early indica rice cv. ‘Shenyou9576’ was conducted in the Key Laboratory of Phytohormones and Growth Development of Hunan Agricultural University, Changsha, Hunan, PR China in 2014 to investigate the influence of varying post-anthesis temperatures on chalkiness rate, head rice rate, and on major 6 starch synthesis enzymes i.e., SuSy (EC 1.9.3.1), ADPG-Ppas (EC 2.7.7.27), SSS (EC 2.4.1.21) and GBSS, (EC 2.4.1.21), SBE (EC 2.4.1.18) and SDBE (EC 3.2.1.70). The treatments comprised of three temperature regimes which are designated as the high (35/28oC- day/night), low (25/20oC- day/night) and natural condition (35/25oC-day/night) as the control. Under high temperature maximum chalkiness rate was 61.11% and minimum was 22.59% under low temperature treatment. The lowest head rice rate was 42.76% under high temperature treatment followed by 49.91% in the control, while the highest rate was 62.33% under low temperature treatment. Maximum grain filling rate (Gmax) was found highest (1.69 mg/day) in the high temperature and average grain filling rate (Gavg) was found highest (1.36 mg/day) under the control. The activity of SuSy, ADPG-Ppase, SSS and GBSS were decreased gradually from 14 to 35 days after flowering (DAF). Irrespective of the treatments, an increasing trend of ADPG-Ppase activity was observed from 7 to 14 DAF and then declined. Correlation between the chalkiness and the enzymes activity of SuSy, ADPG-Ppase and SSS were significantly negative at 21, 28 and 35 DAFs, i.e., higher activity of SuSy, ADPG-Ppase and SSS at the mid-late to the late caryopsis development stage mediated by low temperature treatment played an important role for the reduction of chalkiness. The correlation between GBSS activity and chalkiness was significantly negative and stronger at 14, 21 and 28 DAF indicating that GBSS played a cardinal role to reduce chalkiness in the mid to mid-late stage of rice grain development. Significantly negative correlation was found between starch branching enzyme (SBE) and chalkiness at 21, 28 and 35 DAF, i.e., the higher SBE activity under low temperature treatment at the later grain filling stage also had a positive role in reduction of chalkiness. Bangladesh J. Agril. Res. 44(2): 223-238, June 2019


2021 ◽  
Author(s):  
Jae-Ryoung Park ◽  
Eun-Gyeong Kim ◽  
Yoon-Hee Jang ◽  
Kyung-Min Kim

Abstract Background Recent temperature increases due to rapid climate change have negatively affected rice yield and grain quality. Particularly, high temperatures during rice filling stage from the flowering stage reduce spikelet fertility, while interfering with sugar energy transport, and cause severe damage to grain quality by forming chalkiness grains. The effect of high-temperature on spikelet fertility and grain quality during grain filling stage was evaluated using a double haploid line derived from anther culture of F1 by crossing Cheongcheong and Nagdong cultivars. Quantitative trait locus (QTL) mapping identifies candidate genes significantly associated with spikelet fertility and grain quality at high temperatures. Results Our analysis screened OsSFq3 that contributes to spikelet fertility and grain quality at high-temperature. OsSFq3 was fine-mapped in the region RM15749-RM15689 on chromosome 3, wherein four candidate genes related to the synthesis and decomposition of amylose, a starch component, were predicted. Four major candidate genes, including OsSFq3, and 10 different genes involved in the synthesis and decomposition of amylose and amylopectin, which are starch constituents, together with relative expression levels were analyzed. OsSFq3 was highly expressed during the initial stage of high-temperature treatment. It exhibited high homology with FLOURY ENDOSPERM 6 in Gramineae plants and is therefore expected to function similarly. Conclusion The QTL, major candidate genes, and OsSFq3 identified herein could be effectively used in breeding rice varieties to improve grain quality, while tolerating high temperatures, to cope with climate changes. Furthermore, linked markers can aid in marker-assisted selection of high-quality and -yield rice varieties tolerant to high temperatures.


1992 ◽  
Vol 19 (2) ◽  
pp. 185 ◽  
Author(s):  
SK Sahu ◽  
PK Mohapatra

Growth, spikelet number and assimilate contents of the panicle on the mainshoot of 20 indica rice varieties consisting of four duration groups were measured at intervals during the period between 2 weeks prior to anthesis and maturity. Panicle development was of longer duration in the late maturing varieties than in the early, and grain yield of the former was more than that of the latter due to difference in grain number. Shifting the cultivation of an early duration check variety to match the time of reproductive development in the medium duration group did not change its pattern of development. During development, the concentration of soluble carbohydrates, amino acids and phosphates changed significantly with time, and the pattern was the same in all varieties. Initially the concentration was low, but increased sharply a few days before anthesis to a peak level, then declined until anthesis. After anthesis it decreased to a minimum at maturity. Pre-anthesis metabolite concentration of the panicle was higher in the late varieties than in the early varieties, but not much difference was observed post-anthesis. Growth durations of the vegetative, reproductive and grain filling periods collectively influenced grain yield but, on the basis of partial correlation analysis, the vegetative duration was found most important for yield.


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