Amylose Content In Rice Research Articles

Enhancing the nutritional profile of rice by targeting starch branching enzymes using CRISPR/Cas9

Rice is a fundamental staple in many Asian countries; however, excessive consumption can lead to significant health concerns, including diabetes. One effective strategy to mitigate these concerns is to increase the amylose content in rice, which enhances its resistant starch (RS) levels. Higher RS not only improves the nutritional profile of rice but also positively impacts its cooking qualities, offering various health benefits. Recent research highlights the role of dietary fibers like RS in modulating gut microbiota composition, presenting a promising approach for addressing non-communicable diseases. RS enhances the fermentation activity of gut microbiota, leading to production of beneficial metabolites that support gut barrier function, exhibit anti-inflammatory properties and influence metabolic pathways related to obesity and diabetes. This multifaceted impact on chronic disease outcomes emphasizes the need for rice varieties with increased amylose and consequently higher RS levels, to meet consumer nutritional demands. CRISPR/Cas9, a powerful genome editing tool, allows precise modifications of the targeted genes. This technology can effectively edit starch synthesis-related genes in rice to enhance starch content. This review focuses on the application of CRISPR/Cas9 in increasing RS content in rice and the potential health benefits it could provide to populations that rely on rice as a dietary staple. By integrating genetic innovation with nutritional science, healthier rice varieties can be developed, that align with the dietary needs of consumers.

Evaluation of glycemic index, glycemic load and biochemical traits of rice associated with anti-diabetic properties

Diabetes mellitus, a modern lifestyle disease and metabolic disorder, is closely associated with an increased risk of cardiovascular disease. Research on carbohydrates, particularly white rice with a high glycemic index, has been linked to an increased risk of type II diabetes, heart disease, and cancer. In this study, we aimed to understand the nutritional composition, estimated glycemic index, and glycemic load of twenty-eight rice accessions, particularly focusing on those with low starch digestibility associated with low GI levels. The proximate composition analysis revealed that tested rice accessions exhibited higher levels of genetic variation for amylose (18.45 - 25.97%), phenolic content (5.00-34.08%), protein (5.52-14.54%), and crude fibre (1.64-3.91%) content in brown rice. Huge variability for estimat?ed glycemic index, ranging from low to high GI was observed among all the varieties (49.37 - 78.58%). Traditional varieties viz., Thavalakannan and Kavuni depicted low estimated glycemic index (49.37 % and 54.55 %) and moderate glycemic load (14.60 and 15.80), respectively. The estimated glycemic index exhibited significant and negative association with amylose (r = -0.57**), phenolic (r = -0.67**), and crude fibre (r = -0.52**) content. In contrast, glycemic load showed a significant positive correlation with the amount of carbohydrate content. Principal component analysis revealed considerable variability among rice accessions' biochemical traits with the first two principal components accounting for 68.57% of the total variance. The hierarchical clustering based on Darwin software identified two major clusters. Cluster I comprise popular varieties and Cluster II contains traditional varieties with low to moderate glycemic index. Moreover, identifying rice varieties with lower glycemic index can facilitate the development and enhancement of breeding lines for the diabetic population.

A study on the changes in rice composition under reduced fertilization conditions using Raman spectroscopy technology

The substitution of microbial fertilizer for chemical fertilizer can not only improve soil fertility but also effectively enhance rice quality. To investigate the effect of different amounts of combined application of chemical fertilizer and microbial fertilizer on the amylose content of rice, this study adopts theoretical calculations to compare the preprocessed Raman spectroscopy information of rice with reduced fertilization and establishes a recognition model for the amylose content of rice, which is used to detect the amylose content in rice. Based on the amylose spectral values measured by Raman spectroscopy and the known starch structure and functional groups, the Raman peaks are mainly distributed in the range of 400 cm− 1 to 1400 cm− 1. The Raman characteristic peaks at 483 cm− 1, 869 cm− 1, 933 cm− 1, 1082 cm− 1, 1126 cm− 1, 1335 cm− 1, 1385 cm− 1, and 1455 cm− 1 exhibit strong vibration modes, which are consistent with its main nutrient component of amylose. By comparing the measured amylose content in the regions treated with microbial fertilizer combined with different amounts of reduced fertilization and the spectral intensity values of amylose measured by Raman spectroscopy, the results show that the treatment of combining conventional amounts of microbial fertilizer with different amounts of reduced chemical fertilizer exhibits a decreasing trend in the amylose content of rice.

A mutant allele of the Wx gene encoding granule-bound starch synthase I results in extremely low amylose content in rice.

An amino acid substitution (T506I) in the GT1 domain of granule-bound starch synthase I dramatically reduces amylose content in rice.

Comprehensive modeling of far-infrared drying process for rough rice in a combined FIR dryer

This study introduces a novel single-parameter model for the far-infrared (FIR) drying process of rough rice in a combined FIR dryer, aiming to streamline the prediction process and enhance its efficiency. The experiments involved three levels of FIR intensity (0, 500, and 1000 W m−2) and three levels of inlet air temperature (30, 40, and 50 °C), with a comprehensive examination of various mathematical thin-layer models to predict the drying process. The study developed a comprehensive single-parameter model by investigating the interrelationship of the models’ coefficients under distinct drying conditions, demonstrating its capability to faithfully depict the drying characteristics of rough rice within the combined FIR dryer with an R2 exceeding 0.99. The findings also provide valuable insights into the impact of drying conditions on the drying time, percentage of cracked kernels (PCK), and amylose content of rough rice, revealing increasing trends in PCK and amylose content with higher drying temperature and FIR intensity, offering practical and efficient tools for optimizing the drying process and enhancing the quality of dried rice products. Overall, this research significantly advances rice drying technology and offers practical solutions for improving the efficiency and quality of rice drying processes.

Non-destructive measurement of rice amylose content using near-infrared spectroscopy for application at grain elevators and milling plants

Non-destructive measurement of rice amylose content using near-infrared spectroscopy for application at grain elevators and milling plants

Triple gene mutations boost amylose and resistant starch content in rice: insights from sbe2b/sbe1/OE-Wxa mutants.

Previous studies have modified rice's resistant starch (RS) content by mutating single and double genes. These mutations include knocking out or reducing the expression of sbe1 or sbe2b genes, as well as overexpressing Wxa . However, the impact of triple mutant sbe2b/sbe1/OE-Wxa on RS contents remained unknown. Here, we constructed a double mutant with sbe2b/RNAi-sbe1, based on IR36ae with sbe2b, and a triple mutant with sbe2b/RNAi-sbe1/OE-Wxa , based on the double mutant. The results showed that the amylose and RS contents gradually increased with an increase in the number of mutated genes. The triple mutant exhibited the highest amylose and RS contents, with 41.92% and 4.63%, respectively, which were 2- and 5-fold higher than those of the wild type, which had 22.19% and 0.86%, respectively. All three mutants altered chain length and starch composition compared to the wild type. However, there was minimal difference observed among the mutants. The Wxa gene contributed to the improvement of 1000-grain weight and seed-setting rate, in addition to the highest amylose and RS contents. Thus, our study offers valuable insight for breeding rice cultivars with a higher RS content and yields.

Adjusting the amylose content of semi-glutinous japonica rice by genome editing of uORF6 in the Wx gene

Amylose content, the key determinant of rice eating and cooking quality, is regulated primarily by the Waxy (Wx) gene. We adjusted the amylose content and transparency of semi-glutinous japonica rice carrying the Wxmp allele by genome editing of upstream open reading frame 6 (uORF6) of Wx.

GWAS and Transcriptomic Analysis Identify OsRING315 as a New Candidate Gene Controlling Amylose Content and Gel Consistency in Rice

Cooking quality is the main factor determining the market value of rice. Although several major genes and a certain number of QTLs controlling cooking quality have been identified, the genetic complexity and environmental susceptibility limit the further improvement for cooking quality by molecular breeding. This research conducted a genome-wide association study to elucidate the QTLs related to cooking quality including amylose content (AC), gel consistency (GC) and alkali spreading value (ASV) by using 450 rice accessions consisting of 300 indica and 150 japonica accessions in two distinct environments. A total of 54 QTLs were identified, including 25 QTLs for AC, 12 QTLs for GC and 17 QTLs for ASV. Among them, 10 QTLs were consistently observed by the same population in both environments. Six QTLs were co-localized with the reported QTLs or cloned genes. The Wx gene for AC and GC, and the ALK gene for ASV were identified in every population across the two environments. The qAC9-2 for AC and the qGC9-2 for GC were defined to the same interval. The OsRING315 gene, encoding an E3 ubiquitin ligase, was considered as the candidate gene for both qAC9-2 and qGC9-2. The higher expression of OsRING315 corresponded to the lower AC and higher GC. Three haplotypes of OsRING315 were identified. The Hap 1 mainly existed in the japonica accessions and had lower AC. The Hap 2 and Hap 3 were predominantly present in the indica accessions, associated with higher AC. Meanwhile, the GC of accessions harboring Hap 1 was higher than that of accessions harboring Hap 3. In addition, the distribution of the three haplotypes in several rice-growing regions was unbalanced. The three traits of cooking quality are controlled by both major and minor genes and susceptible to environmental factors. The expression level of OsRING315 is related to both AC and GC, and this gene can be a promising target in quality improvement by using the gene editing method. Moreover, the haplotypes of OsRING315 differentiate between indica and japonica, and reveal the differences in GC and AC between indica and japonica rice.

ABA-mediated regulation of rice grain quality and seed dormancy via the NF-YB1-SLRL2-bHLH144 Module.

Abscisic acid (ABA) plays a crucial role in promoting plant stress resistance and seed dormancy. However, how ABA regulates rice quality remains unclear. This study identifies a key transcription factor SLR1-like2 (SLRL2), which mediates the ABA-regulated amylose content (AC) of rice. Mechanistically, SLRL2 interacts with NF-YB1 to co-regulate Wx, a determinant of AC and rice quality. In contrast to SLR1, SLRL2 is ABA inducible but insensitive to GA. In addition, SLRL2 exhibits DNA-binding activity and directly regulates the expression of Wx, bHLH144 and MFT2. SLRL2 competes with NF-YC12 for interaction with NF-YB1. NF-YB1 also directly represses SLRL2 transcription. Genetic validation supports that SLRL2 functions downstream of NF-YB1 and bHLH144 in regulating rice AC. Thus, an NF-YB1-SLRL2-bHLH144 regulatory module is successfully revealed. Furthermore, SLRL2 regulates rice dormancy by modulating the expression of MFT2. In conclusion, this study revealed an ABA-responsive regulatory cascade that functions in both rice quality and seed dormancy.

Agronomic biofortification of basmati rice (Oryza sativa L.) through iron and boron under varying seedling densities

At present, we have adequate production of rice to fulfill the needs of humans. Now it is time to produce biofortified rice, whose grains contain enough amounts of nutrients like iron and boron. Two field experiments were carried out in Kharif 2019 and 2020 at Meerut (Uttar Pradesh), India, to find the effect of iron and boron nutrition on rice with different planting densities. The main plot treatment consists of three planting densities, and the subplot treatment consists of five foliar applications of micronutrients. They were tested in a split-plot design (SPD) with three replications. The results revealed that the rice transplanted with one seedling/hill gave the highest iron and boron content in grains and/or the crop fortified with iron and boron at 0.1 and 0.04% applied at the maximum tillering (MT) and panicle initiation (PI) stages of rice, respectively. The higher values of yield-contributing characters such as effective tillers/m2, panicle length (cm), grain weight/panicle (g), and test weight (g), as well as quality parameters such as nutrient content in grain (mg/kg), volume expansion ratio, protein content in grains (%), and amylose content (%) of rice were noticed in one seedling/hill except effective tillers/m2 during the first and second years. Application of Fe and B at the MT and PI stages of rice improved almost all the yield attributes and quality parameters. Planting density of two and three seedlings/hill was recorded at par values of grain yield, followed by one seedling/hill. Rice transplanted with three seedlings/hill obtained an average of 10.1 and 10.6% more grain yield than one seedling/hill during the first and second years, respectively. However, the application of Fe at 0.1% and B at 0.04% during both stages through foliar spray resulted in the highest seed yield and showed parity with the application of iron at 0.1% at the MT stage and boron at 0.04% at the PI stage. Economics revealed that the planting density of three seedlings/hill gave the maximum net returns of 61,585 and 66,752 ₹/ha with a benefit–cost ratio of 2.12 and 2.19 during 2019 and 2020, respectively. Furthermore, the highest net returns (62,188 and 67,938 ₹/ha) and benefit–cost ratio (2.15 and 2.23) were observed from the treatment of iron at 0.1% and boron at 0.04% at the MT and PI stages during the first and second years, respectively.

Biofortified Rice Provides Rich Sakuranetin in Endosperm

Sakuranetin plays a key role as a phytoalexin in plant resistance to biotic and abiotic stresses, and possesses diverse health-promoting benefits. However, mature rice seeds do not contain detectable levels of sakuranetin. In the present study, a transgenic rice plant was developed in which the promoter of an endosperm-specific glutelin gene OsGluD-1 drives the expression of a specific enzyme naringenin 7-O-methyltransferase (NOMT) for sakuranetin biosynthesis. The presence of naringenin, which serves as the biosynthetic precursor of sakuranetin made this modification feasible in theory. Liquid chromatography tandem mass spectrometry (LC–MS/MS) validated that the seeds of transgenic rice accumulated remarkable sakuranetin at the mature stage, and higher at the filling stage. In addition, the panicle blast resistance of transgenic rice was significantly higher than that of the wild type. Specially, the matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) imaging was performed to detect the content and spatial distribution of sakuranetin and other nutritional metabolites in transgenic rice seeds. Notably, this genetic modification also did not change the nutritional and quality indicators such as soluble sugars, total amino acids, total flavonoids, amylose, total protein, and free amino acid content in rice. Meanwhile, the phenotypes of the transgenic plant during the whole growth and developmental periods and agricultural traits such as grain width, grain length, and 1000-grain weight exhibited no significant differences from the wild type. Collectively, the study provides a conceptual advance on cultivating sakuranetin-rich biofortified rice by metabolic engineering. This new breeding idea may not only enhance the disease resistance of cereal crop seeds but also improve the nutritional value of grains for human health benefits.

Mapping of QTL associated with rice cooking quality and candidate gene analysis

Excavating the quantitative trait locus (QTL) associated with rice cooking quality, analyzing candidate genes, and improving cooking quality-associated traits of rice varieties by genetic breeding can effectively improve the taste of rice. In this study, we used the indica rice HZ, the japonica rice Nekken2 and 120 recombinant inbred lines (RILs) populations constructed from them as experimental materials to measure the gelatinization temperature (GT), gel consistency (GC) and amylose content (AC) of rice at the maturity stage. We combined the high-density genetic map for QTL mapping. A total of 26 QTLs associated with rice cooking quality (1 QTL associated with GT, 13 QTLs associated with GC, and 12 QTLs associated with AC) were detected, among which the highest likelihood of odd (LOD) value reached 30.24. The expression levels of candidate genes in the localization interval were analyzed by quantitative real-time polymerase chain reaction (qRT-PCR), and it was found that the expression levels of six genes were significantly different from that in parents. It was speculated that the high expression of LOC_Os04g20270 and LOC_Os11g40100 may greatly increase the GC of rice, while the high expression of LOC_Os01g04920 and LOC_Os02g17500 and the low expression of LOC_Os03g02650 and LOC_Os05g25840 may reduce the AC. The results lay a molecular foundation for the cultivation of new high-quality rice varieties, and provide important genetic resources for revealing the molecular regulation mechanism of rice cooking quality.

Physicochemical properties and molecular mechanisms of different resistant starch subtypes in rice.

Resistant starch (RS) can help prevent diabetes and decrease calorie intake and that from plants are the main source of mankind consumption. Rice is many people's staple food and that with higher RS will help health management. A significantly positive correlation exists between apparent amylose content (AAC) of rice and its RS content. In this study, 72 accessions with moderate or high AAC were selected to explore the regulatory mechanisms and physicochemical properties on different proceeding types of rice RS. RS in raw milled rice (RSm), hot cooked rice (RSc), and retrogradation rice (RSr) showed a wide variation and distinct controlling mechanisms. They were co-regulated by Waxy (Wx), soluble starch synthase (SS) IIb and SSI. Besides that, RSm was also regulated by SSIIa and SSIVb, RSc by granule-bound starch synthase (GBSS) II and RSr by GBSSII and Pullulanase (PUL). Moreover, Wx had significant interactions with SSIIa, SSI, SSIIb and SSIVb on RSm, but only the dominant interactions with SSIIb and SSI on RSc and RSr. Wx was the key factor for the formation of RS, especially the RSc and RSr. The genes had the highest expression at 17 days after flowering and were beneficial for RS formation. The longer the chain length of starch, the higher the RS3 content. RSc and RSr were likely to be contained in medium-size starch granules. The findings favor understanding the biosynthesis of different subtypes of RS.

Determination of amylose content of traditional rice varieties of Kerala using PCR-based molecular markers

The present study uses molecular approach to assess the amount of amylose in collected rice genotypes using PCR based markers. The polymorphism of Waxy allele which encodes the major enzyme catalyzing amylose synthesis was analyzed in the collected rice samples to determine the amylose content in the samples. All the rice varieties under study expressed Wxa allele corresponding to intermediate to high amylose content. This study proves that simple PCR technique can be used to detect Single nucleotide polymorphism mutation at Wx locus and provides a cost-effective alternative to predict amylose content in rice.

Effects of Different Cooking Methods on Glycemic Index, Physicochemical Indexes, and Digestive Characteristics of Two Kinds of Rice

Diets including rice and rice-cooking methods influence digestive processes and blood glucose control. In this research, the effects of three different treatments (high-temperature and low-pressure plasma cooking, high-temperature cooking at atmospheric pressure (traditional method), and high-temperature cooking at high pressure) on the texture, color, molecular structure, infrared spectrum, microstructure, debranching enzyme activity, amylopectin content, glycemic index (GI), and in vitro starch digestibility of two rice varieties were studied. The results showed that the hardness, elasticity, viscosity, and chewability of rice after the high-temperature and low-pressure plasma treatment had no obvious changes compared with the traditional cooking method. A SEM analysis showed that the physical properties of the hydrophilicity on the surface of the rice increased after the high-temperature and low-pressure plasma treatment; the debranching enzyme activity reached 3.88 U/g (Xiantao rice) and 3.81 U/g (Heyuan rice), respectively, the amylose content of raw rice reached 68.77 mg/mL (Xiantao rice) and 64.92 mg/mL (Heyuan rice), which increased by 43.31 mg/mL and 39.46 mg/mL, respectively, and the GI was within the medium glycemic index of 56–69. The resistant starch in the Heyuan and Xiantao rice varieties amounted to 88.60 ± 3.10% and 89.40 ± 3.58%, respectively, after the high-temperature and low-pressure plasma processing method. The results showed positive effects and application potential for the cooking method in respect of diabetic consumers.

Performance of Advanced Machine Learning Models in the Prediction of Amylose Content in Rice Using Internet of Things-Based Colorimetric Sensor

Performance of Advanced Machine Learning Models in the Prediction of Amylose Content in Rice Using Internet of Things-Based Colorimetric Sensor

Association Mapping of Amylose Content in Maize RIL Population Using SSR and SNP Markers.

The ratio of amylose to amylopectin in maize kernel starch is important for the appearance, structure, and quality of food products and processing. This study aimed to identify quantitative trait loci (QTLs) controlling amylose content in maize through association mapping with simple sequence repeat (SSR) and single-nucleotide polymorphism (SNP) markers. The average value of amylose content for an 80-recombinant-inbred-line (RIL) population was 8.8 ± 0.7%, ranging from 2.1 to 15.9%. We used two different analyses-Q + K and PCA + K mixed linear models (MLMs)-and found 38 (35 SNP and 3 SSR) and 32 (29 SNP and 3 SSR) marker-trait associations (MTAs) associated with amylose content. A total of 34 (31 SNP and 3 SSR) and 28 (25 SNP and 3 SSR) MTAs were confirmed in the Q + K and PCA + K MLMs, respectively. This study detected some candidate genes for amylose content, such as GRMZM2G118690-encoding BBR/BPC transcription factor, which is used for the control of seed development and is associated with the amylose content of rice. GRMZM5G830776-encoding SNARE-interacting protein (KEULE) and the uncharacterized marker PUT-163a-18172151-1376 were significant with higher R2 value in two difference methods. GRMZM2G092296 were also significantly associated with amylose content in this study. This study focused on amylose content using a RIL population derived from dent and waxy inbred lines using molecular markers. Future studies would be of benefit for investigating the physical linkage between starch synthesis genes using SNP and SSR markers, which would help to build a more detailed genetic map and provide new insights into gene regulation of agriculturally important traits.

Effect of Rural Sewage Irrigation Regime on Water-Nitrogen Utilization and Crop Growth of Paddy Rice in Southern China

Reclaimed water irrigation has become an effective mean to alleviate the contradiction between water availability and its consumption worldwide. In this study, three types of irrigation water sources (rural sewage’s primary treated water R1 and secondary treated water R2, and river water R3) meeting the requirements of water quality for farmland irrigation were selected, and three types of irrigation water levels (low water level W1 of 0–80 mm, medium water level W2 of 0–100 mm, and high water level W3 of 0–150 mm) were adopted to carry out research on the influence mechanismS of different irrigation water sources and water levels on water and nitrogen use and crop growth in paddy field. The water quantity indicators (irrigation times and irrigation volume), soil ammonium nitrogen (NH4+-N) and nitrate nitrogen (NO3−-N), rice yield indicators (thousand-grain weight, the number of grains per spike, and the number of effective spikes), and quality indicators (the amount of protein, amylose, vitamin C, nitrate and nitrite content) of rice were measured. The results showed that, the average irrigation volume under W3 was 2.4 and 1.9 times of that under W1 and W2, respectively. Compared with R3, the peak consumption of rice was lagged behind under R1 and R2, and the nitrogen form in 0–40 cm soil layers under rural sewage irrigation was mainly NH4+-N. The changes of NO3−-N and NH4+-N in the 0–40 cm soil layer showed the trend of declining and then increasing. The water level control only had a significant effect on the change of NO3−-N in the 60–80 cm soil layer. Both irrigation water use efficiency and crop water use efficiency were gradually reduced with the increase of field water level control. The nitrogen utilization efficiency under rural sewage irrigation was significantly higher than that under R3. Compared with the R3, rural sewage irrigation could significantly increase the yield of rice, and as the field water level rose, the effect of yield promotion was more obvious. It was noteworthy that the grain of rice under R1 monitored the low nitrate and nitrite content, but no nitrate and nitrite was discovered under R2 and R3. Therefore, reasonable rural sewage irrigation (R2) and medium water level (W2) were beneficial to improve nitrogen utilization efficiency, crop yield and crop quality promotion.

Impact of Drying Techniques on Physicochemical Properties of Dried Rice and Its Influences on Rice Beer Brewing Process

Highlights Implications of microwave drying on rice brewing performance were tested. Microwave-dried rice is most similar to natural air-dried rice in protein and amylose content. Microwave-dried rice is most similar to natural air-dried rice in brewing utilization. Abstract. Rice is used as an adjunct grain by the beer manufacturing industry. Before utilization, the rice has to be dried to the desired moisture content. The drying process employed may have an impact on the rice’s physicochemical properties, which influence the rice’s performance in the brewing process. This study focused on investigating the impact of microwave drying on rice’s physicochemical properties and utilization in the brewing process. Rough rice samples with an initial moisture content of 19.7% wet basis were exposed to a microwave dryer to deliver specific energy at the rate of 525 kJ/Kg of initial grain mass in a single drying pass. The effects of the single-pass continuous drying on the dried rice amylose content, protein content, and specific gravity (°Plato, fermentable sugar content) of the wort were determined. The results were compared with samples dried using natural air at 25°C and 56% relative humidity (RH) and two-pass hot-air drying at 45°C and 60°C with RH set at 20%. There was a statistical difference in measured rice amylose and protein contents (p= 0.042) between microwave-dried samples and the natural air-dried samples. However, these attributes were significantly different from those of samples dried at a higher temperature of 60°C and an RH of 20%. There was a significant difference (p=0.0197) in the initial gravity content of the all-malt samples and the rice adjunct samples, as expected, but there was no significant difference between the rice adjunct samples. Overall, this study analyzed the effect of microwave drying on rice processing and its subsequent use in the brewing process, but no measurable differences were observed among the wort’s initial and final gravity contents, attenuation levels, and alcohol by volume. Microwave drying was most comparable to natural air drying, but it results in a greater head rice yield, which may benefit rice farmers and processors. Keywords: Amylose content, Brewing process, Microwave drying, Rice drying, Specific gravity.