scholarly journals Grain Quality and Starch Physicochemical Properties of Chalky Rice Mutant

Agronomy ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 1575
Author(s):  
Chu-Xin Wang ◽  
Cheng-Chao Zhu ◽  
Chen-Ya Lu ◽  
Yong Yang ◽  
Qian-Feng Li ◽  
...  

Rice mutants with altered starch components and properties are important genetic resources for grain quality and starch structure analysis. Accordingly, in the present study, two mutants of the transcription factor OsbZIP09 were generated (osbzip09a and osbzip09b), and the rice grain quality and physicochemical starch properties of the mutant and wild-type lines were compared. The OsbZIP09 mutants exhibit a chalky grain owing to loosely packed, small, spherical starch granules in the ventral region of the endosperm. Furthermore, grain-quality profile analysis showed that OsbZIP09 deficiency leads to increased apparent amylose content but decreased gel consistency. Structural analysis of the mutant starches revealed that the mutant rice lines contain more amylopectin short chains and fewer intermediate chains, leading to lower crystallinity and lower gelatinization properties than those of the wild-type rice. Moreover, the OsbZIP09 mutants rice presented a significantly higher pasting curve and corresponding parameters than the wild-type rice. The results from this work strongly indicate that the transcription factor OsbZIP09 plays an important role in rice grain quality and starch fine structure modification, and extend our understanding of starch biosynthesis in rice endosperm.

1998 ◽  
Vol 6 (A) ◽  
pp. A111-A116 ◽  
Author(s):  
Naoto Shimizu ◽  
Jyunji Katsura ◽  
Takashi Yanagisawa ◽  
Bunji Tezuka ◽  
Yasuyuki Maruyama ◽  
...  

The development of advanced evaluation techniques for rice quality has been a desire of the Japanese rice industry (breeding, distribution and processing). The objective of the present study is to develop novel techniques for evaluating rice grain quality. A reliable determination method for amylose in whole grain rice using near infrared transmission (NIT) is proposed, using Partial Least Squares (PLS) regression analysis. It was suggested from results based on two different validation methods that the PLS models have possibilities for determination of apparent amylose content using NIT spectroscopy. PLS modelling for constituents important in rice quality indicates that reasonably accurate models are attainable for moisture content and protein content in whole grain rice. However our PLS models were not sufficiently accurate for physical rice quality (head rice ratio, apparent density, whiteness) using NIT spectroscopy.


Plants ◽  
2020 ◽  
Vol 9 (3) ◽  
pp. 390
Author(s):  
Muhammad Saad Shoaib Khan ◽  
Rasbin Basnet ◽  
Sulaiman Ahmed ◽  
Jinsong Bao ◽  
Qingyao Shu

Phospholipids belong to a significant class of lipids and comprise ~10% of total lipids in rice grains. Lysophospholipid (LPL) is derived from the hydrolysis of phospholipids and plays an important role in rice grain quality. Our previous study demonstrated that mutations in a phospholipase D gene (OsPLDα1) significantly altered lipid metabolites and reduced phytic acid content. In the present study, the effect of two ospldα1 mutations on LPL and other physicochemical prosperities of brown rice was further investigated, with the aim of assessing the overall importance of ospldα1 mutations in rice grain quality. Metabolite profiling revealed a ~15% increase in LPL level in both ospldα1 mutants as compared with their wild-type (WT) parent. Both ospldα1 mutations significantly lowered the apparent amylose content in brown rice flour (~1.9%) and altered viscosity profiles with significantly increased breakdown (+12.4%) and significantly reduced setback viscosity (−6.2%). Moreover, both ospldα1 mutations significantly lowered the gelatinization onset, peak temperature and retrogradation percentage of brown rice flour. This study demonstrated that OsPLDα1 plays a crucial role in rice grain quality and its mutation could, in general, improve the cooking and eating quality and nourishment of brown rice.


Agronomy ◽  
2018 ◽  
Vol 8 (11) ◽  
pp. 246 ◽  
Author(s):  
Chanchan Zhou ◽  
Yuancai Huang ◽  
Baoyan Jia ◽  
Yan Wang ◽  
Yun Wang ◽  
...  

To achieve superior rice-grain quality, more emphasis has been placed on the genetic diversity of breeding programs, although this improvement could be seriously restricted in the absence of comparable agricultural management practices. Nitrogen (N) application and planting density are two important agronomic practices influencing rice growth, yield, and grain quality. This study investigated the four main aspects of rice-grain quality, namely, milling (brown-rice, milled-rice, and head-rice percentage), appearance (length/width ratio, chalky-kernel percentage, and chalkiness), nutrition (protein content), and cooking and eating quality (apparent amylose content, gel consistency, and pasting viscosities) of two rice cultivars (Shendao 47 and Jingyou 586) under four N rates (0, 140, 180, and 220 kg ha−1), and three planting densities (25 × 104, 16.7 × 104, and 12.5 × 104 hills ha−1) in a field trial from 2015 to 2016. The four main aspects of rice-grain quality were significantly influenced by cultivar. Several aspects were affected by the interactions of N rate and cultivar. No significant interaction between N rate and plating density was detected for all grain-quality parameters. A higher N rate increased the percentages of brown rice and head rice, chalky-kernel percentage, and setback and peak time values, but reduced the length/width ratio, chalkiness, apparent amylose content, gel consistency, and peak-, trough-, and final-viscosity values. These results indicate that the N rate has a beneficial effect on milling and nutritional quality, but a detrimental effect on appearance and cooking and eating quality. Jingyou 586 and Shendao 47 had different responses to planting density in terms of grain quality. Our study indicates that low planting density for Jingyou 586, but a medium one for Shendao 47, is favorable for grain quality.


Agriculture ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 325
Author(s):  
Ramin Rayee ◽  
Tran Dang Xuan ◽  
Tran Dang Khanh ◽  
Hoang-Dung Tran ◽  
Kifayatullah Kakar

The management of amylose and protein contents and cooking quality are the main challenges in rice macronutrients and quality improvement. This experiment was conducted to examine the rice grain quality, alkali digestion, and gel consistency responses to irrigation interval after anthesis. Three rice varieties (K1, K3, and K4) were subjected to different irrigation intervals (1, 2, and 3 d) after anthesis. The findings of this study showed that the protein content was markedly increased from 6.53–6.63% to 9.93–10.16%, whilst the amylose content was decreased significantly from 22.00–22.43% to 16.33–17.56% under stressed treatments at irrigation intervals, whilst the quantity of fatty acids was not affected. The 3-d irrigation interval recorded the highest protein content but the lowest amylose value. In addition, this treatment shows lower gelatinization temperature, but it is negatively associated with hard gel consistency under irrigation interval. This study highlights that the water management following a 3-d irrigation interval from anthesis is a useful and simple treatment to improve rice nutrients and grain cooking quality.


2018 ◽  
Vol 2018 ◽  
pp. 1-11
Author(s):  
María D. Torres ◽  
Francisco Chenlo ◽  
Ramón Moreira

The influence of roasting conditions on the potato starch (PS) composition, solubility, crystallinity, gel-forming thermal profiles, and texture of the corresponding gels was studied. Thermorheological testing of roasted starches with (RPS) and without (RPSI) the soluble fraction was conducted on a stress-controlled rheometer. Texture profile analysis (TPA) was used to determine the RPS final gel texture. Solubility tests showed equivalent effects of starch roasting for samples treated at 190°C for 8 h (RPS190-8), 210°C for 6 h (RPS210-6), and 230°C for 4 h (RPS230-4). The apparent amylose content of RPS linearly increased with the decreasing degree of crystallinity. Elastic (G′) and viscous (G″) properties of RPS depended markedly on apparent amylose content and crystallinity. G′gel values of roasted starches linearly increased with the amylose content suggesting a promotion of the amylose breakdown with roasting temperature. Gels prepared with RPS roasted between 120 and 170°C exhibited intermediate strength and fully thermal reversible features. Roasting between 190 and 210°C favoured strong and fully thermal reversible gels. Although RPS230-4 gels exhibited similar strength to RPS190-8 and RPS210-4, no fully thermal reversible gels were obtained. The soluble fraction removal led to a drop the RPSI gels strength with increasing roasting temperature. No water syneresis was identified for RPS gels during one-week ageing, except for RPS230 gels. Relationships between textural parameters from TPA and viscoelastic gel properties determined by rheology were established.


2019 ◽  
Vol 20 (3) ◽  
pp. 483 ◽  
Author(s):  
Kangyong Zha ◽  
Haoxun Xie ◽  
Min Ge ◽  
Zimeng Wang ◽  
Yu Wang ◽  
...  

As major component in cereals grains, starch has been one of the most important carbohydrate consumed by a majority of world’s population. However, the molecular mechanism for regulation of biosynthesis of starch remains elusive. In the present study, ZmES22, encoding a MADS-type transcription factor, was modestly characterized from maize inbred line B73. ZmES22 exhibited high expression level in endosperm at 10 days after pollination (DAP) and peaked in endosperm at 20 DAP, indicating that ZmES22 was preferentially expressed in maize endosperm during active starch synthesis. Transient expression of ZmES22 in tobacco leaf revealed that ZmES22 protein located in nucleus. No transactivation activity could be detected for ZmES22 protein via yeast one-hybrid assay. Transformation of overexpressing plasmid 35S::ZmES22 into rice remarkedly reduced 1000-grain weight as well as the total starch content, while the soluble sugar was significantly higher in transgenic rice lines. Moreover, overexpressing ZmES22 reduced fractions of long branched starch. Scanning electron microscopy images of transverse sections of rice grains revealed that altered expression of ZmES22 also changed the morphology of starch granule from densely packed, polyhedral starch granules into loosely packed, spherical granules with larger spaces. Furthermore, RNA-seq results indicated that overexpressing ZmES22 could significantly influence mRNA expression levels of numerous key regulatory genes in starch synthesis pathway. Y1H assay illustrated that ZmES22 protein could bind to the promoter region of OsGIF1 and downregulate its mRNA expression during rice grain filling stages. These findings suggest that ZmES22 was a novel regulator during starch synthesis process in rice endosperm.


2019 ◽  
Vol 70 (6) ◽  
pp. 486 ◽  
Author(s):  
Fengxian Zhen ◽  
Wei Wang ◽  
Haoyu Wang ◽  
Junjie Zhou ◽  
Bing Liu ◽  
...  

Extreme heat-stress events are becoming more frequent under anticipated global warming, which is having devastating effect on grain yield, as well as quality, of rice (Oryza sativa L.). The effects of heat stress at booting stage on grain quality of two japonica varieties, Nanjing41 and Wuyunjing24, were investigated in phytotrons during 2014 and 2015. Rice plants were subjected to four mean temperature regimes 27°C, 31°C, 35°C and 39°C of 2, 4 and 6 days’ duration. The results showed that high temperatures of 35°C and 39°C for 4 and 6 days significantly reduced panicle size, seed-setting rate, grain size, chalky grain rate, milling characteristics and amylose content, but increased protein content. Severe heat stress decreased values of peak viscosity and breakdown, and increased pasting temperature. An increase in heat degree-days decreased the percentage of chalky grains exponentially, and decreased amylose content and increased protein content linearly. Sensitivity of grain quality to heat stress in the two varieties differed among quality traits and with heat stress intensity. This study indicates that rice-grain quality had some resistance to mild heat stress, but it could not withstand severe heat stress at booting. Short-term heat stress at booting stage deteriorates most grain-quality traits, posing a potential risk to rice quality. The impacts on grain quality could be well quantified by the combined effects of the intensity and duration of heat stress at booting stage.


2021 ◽  
Vol 58 (Special) ◽  
pp. 208-220
Author(s):  
Torit Baran Bagchi ◽  
Sarangadhar Nayak ◽  
Monalisha Biswal ◽  
Soumya Kumar Sahoo ◽  
Awadhesh Kumar

Rice grain quality is the most important factor for evaluation of a variety as well as millers, consumers and farmer's point of view. It includes physico-chemical, nutritional and sensory qualities. The consumers of India and other south east Asian countries prefer medium to high amylose content (AC) rice due to their non-stickiness properties of boiled rice but in many Asian countries, waxy rice (having low AC) mainly preferred. The colour of rice grain may be white, purple, red and black; which are mainly associated with pericarp or bran layers of the whole grain. The bran contains most of the phytochemicals like oils, antioxidants, minerals, proteins, vitamins and crude fibers in higher concentration than white endosperm. Pigmented rice is generally rich in nutritional compounds as compared to white one but those are unpopular among the farmers because of many undesirable physiological and agronomic characteristics. Sensory qualities like colour, texture, pasting properties, aroma are essential for consumers as per their preference and acceptance. As rice grain is mainly composed by starch, hydrolyzed by digestive enzymes and converted into glucose which is the major energy source for various metabolic functions. After fulfilling the body energy requirement, extra calories from starch are stored as fats or glycogen for later use. Therefore, overeating food containing rice with sedentary lifestyle potentially leads to some health issues, such as type-II diabetes, obesity and colon diseases in long term particularly in Asian countries. Various biochemical factors affect the starch digestibility and Glycemic index (GI) of a food or its products. These factors are resistant starch, AC and phytic acid which lowers the starch digestibility by various ways and have been negatively correlated with GI value. Now-a-days quality assessment of rice grain in terms of its nutritional as well as physico-chemical parameters is gaining prime importance gradually.


2021 ◽  
Author(s):  
Xingdan Liu ◽  
Qi Ding ◽  
Wenshu Wang ◽  
Yanling Pan ◽  
Chao Tan ◽  
...  

Abstract Background: Rice Waxy (Wx) gene plays a major role in seed amylose synthesis, and consequently controls grain amylose content. The expression of Wx gene is highly regulated at both transcriptional and post-transcriptional levels. Particularly, the GT/TT poplymorphism at the 5` splicing site of its 1st intron greatly affects this intron’s splicing efficiency and defines two predominant Wx alleles, Wxa and Wxb. Wxa rice often has intermediate to high amylose content, whereas Wxb rice has low to intermediate amylose content. A previous study indicates that rice Wx 1st intron significantly enhances gene expression when it is inserted into the 5` UTR (untranslated region) of a foreign gene. By deleting Wx 1st intron with the CRISPR/Cas9 technology, we intended to create a totally noval Wx allele, and further to investigate how the intron removal affects Wx gene expression and rice grain amylose content.Results: CRISPR/Cas9-mediated targeted deletion of Wx 1st intron was performed on 4 rice inbreds, KY131(Wxb), X32(Wxb), X35(Wxa) and X55(Wxlv). Complete deletion of the 1st intron occurred in 8.6%-11.8% of the primary transformants of these 4 inbreds. Transgene-free, homozygous mutants were obtained. Their grain amylose content and Wx gene expression were analyzed. Compared to the amylose content of wild type plants, mutants’ amylose content was significantly increased from 13.0% to about 24% in KY131 and X32 which both carried the Wxb allele. However, no significant differenece in aylose content was observed between wild type plants and mutants of X35 and X55 which carried the Wxa and Wxlv allele, respectively. Results of Wx gene expression analysis on wild type plants and mutants showed a high consistence with their amylose content results. Mutants of KY131 and X32 accumulated much more steady mRNA transcripts than their wild type plants, while steady mRNA level remained somehow unchanged between wild type plants and mutants of X35 and X55. Grain quality including appearance quality and ECQ(eating and cooking quality) that are tightly linked to amylose content was also evalued on wild type plants and mutants, and data were presented and analyzed. Conclusions:This study presents a novel and fast strategy to increase amylose content for rice inbreds carrying a Wxb allele. Our data strongly suggest that rice Wx 1st intron regulates Wx gene expression mainly at the post-transcriptinal level, not as previously thought that it influences Wx gene transcription as well. In addition, removal of the first intron creates a completely noval Wx allele. Further studies on this new Wx allele would provide invaluable insights into the regulation of Wx gene expression, which will help researchers to engineer more new alleles that leads to the breeding of rice cultivars with better eating and cooking quality.


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