Search

Background: Salinity is one of the main abiotic factors that restrict plant growth, physiology, and crop productivity is salt stress. About 33% of the total irrigated land suffers from severe salinity because of intensive underground water extraction and irrigation with brackish water. Thus, it is important to understand the genetic mechanism and identify the novel genes involved in salt tolerance for the development of climate-resilient rice cultivars. Methods and results: In this study, two rice genotypes with varying tolerance to salt stress were used to investigate the differential expressed genes and molecular pathways to adapt under saline soil by comparative RNA sequencing at 42 days of the seedling stage. Salt-susceptible (S3) and -tolerant (S13) genotypes revealed 3982 and 3463 differentially expressed genes in S3 and S13 genotypes. The up-regulated genes in both genotypes were substantially enriched in different metabolic processes and binding activities. Biosynthesis of secondary metabolites, phenylpropanoid biosynthesis, and plant signal transduction mechanisms were highly enriched. Salt-susceptible and -tolerant genotypes shared the same salt adaptability mechanism with no significant quantitative differences at the transcriptome level. Moreover, bHLH, ERF, NAC, WRKY, and MYB transcription factors were substantially up-regulated under salt stress. 391 out of 1806 identified novel genes involved in signal transduction mechanisms. Expression profiling of six novel genes further validated the findings from RNA-seq data. Conclusion: These findings suggest that the differentially expressed genes and molecular mechanisms involved in salt stress adaptation are conserved in both salt-susceptible and salt-tolerant rice genotypes. Further molecular characterization of novel genes will help to understand the genetic mechanism underlying salt tolerance in rice. [ABSTRACT FROM AUTHOR]

The correction notice in the Scientific Reports journal addresses an error in the listing of corresponding authors for an article on rice lines under water deficit stress. Mohamed Abdelrahman was incorrectly listed as a corresponding author, with Areej S. Jalal being the correct corresponding author. The correction has been made to the original article, which can be accessed online. [Extracted from the article]

Rice plants experience various biotic (such as insect and pest attack) and abiotic (such as drought, salt, heat, and cold etc.) stresses during the growing season, resulting in DNA damage and the subsequent losses in rice production. DNA Replication Helicase/Nuclease2 (DNA2) is known to be involved in DNA replication and repair. In animals and yeast DNA2 are well characterized because it has the abilities of both helicase and nuclease, it plays a crucial role in DNA replication in the nucleus and mitochondrial genomes. However; they are not fully examined in plants due to less focused on plants damage repair. To fill this research gap, the current study focused on the genome-wide identification and characterization of OsDNA2 genes, along with analyses of their transcriptional expression, duplication, and phylogeny in rice. Overall, 17 OsDNA2 members were reported to be found on eight different chromosomes (2, 3, 4, 6, 7, 9, 10, and 11). Among these chromosomes (Chr), Chr4 contained a maximum of six OsDNA2 genes. Based on phylogenetic analysis, the OsDNA2 gene members were clustered into three different groups. Furthermore, the conserved domains, gene structures, and cis-regulatory elements were systematically investigated. Gene duplication analysis revealed that OsDNA2_2 had an evolutionary relationship with OsDNA2_14, OsDNA2_5 with OsDNA2_6, and OsDNA2_1 with OsDNA2_8. Moreover, results showed that the conserved domain (AAA_11 superfamily) were present in the OsDNA2 genes, which belongs to the DEAD-like helicase superfamily. In addition, to understand the post-transcriptional modification of OsDNA2 genes, miRNAs were predicted, where 653 miRNAs were reported to target 17 OsDNA2 genes. The results indicated that at the maximum, OsDNA2_1 and OsDNA2_4 were targeted by 74 miRNAs each, and OsDNA2_9 was less targeted (20 miRNAs). The three-dimensional (3D) structures of 17 OsDNA2 proteins were also predicted. Expression of OsDNA2 members was also carried out under drought and salt stresses, and conclusively their induction indicated the possible involvement of OsDNA2 in DNA repair under stress when compared with the control. Further studies are recommended to confirm where this study will offer valuable basic data on the functioning of DNA2 genes in rice and other crop plants. [ABSTRACT FROM AUTHOR]

The widespread impacts of projected global and regional climate change on rice yield have been investigated by different indirect approaches utilizing various simulation models. However, direct approaches to assess the impacts of climatic variabilities on rice growth and development may provide more reliable evidence to evaluate the effects of climate change on rice productivity. Climate change has substantially impacted rice production in the mid-high latitudes of China, especially in Northeast China (NEC). Climatic variabilities occurring in NEC since the 1970s have resulted in an obvious warming trend, which made this region one of the three major rice-growing regions in China. However, the projections of future climate change have indicated the likelihood of more abrupt and irregular climatic changes, posing threats to rice sustainability in this region. Hence, understanding the self-adaptability and identifying adjustive measures to climate variability in high latitudes has practical significance for establishing a sustainable rice system to sustain future food security in China. A well-managed field study under randomized complete block design (RCBD) was conducted in 2017 and 2018 at two study sites in Harbin and Qiqihar, located in Heilongjiang province in NEC. Four different cultivars were evaluated: Longdao-18, Longdao-21 (longer growth duration), Longjing-21, and Suijing-18 (shorter growth duration) to assess the inter-relationships among grain-filling parameters, grain yield and yield components, and grain quality attributes. To better compare the adaptability mechanisms between grain-filling and yield components, the filling phase was divided into three sub-phases (start, middle, and late). The current study evaluated the formation and accumulation of the assimilates in superior and inferior grains during grain-filling, mainly in the middle sub-phase, which accounted for 59.60% of the yield. The grain yields for Suijing-18, Longjing-21, Longdao-21, and Longdao-18 were 8.02%, 12.78%, 17.19%, and 20.53% higher in Harbin than those in Qiqihar, respectively in 2017, with a similar trend observed in 2018. At Harbin, a higher number of productive tillers was noticed in Suijing-18, with averages of 17 and 15 in 2017 and 2018, respectively. The grain-filling parameters of yield analysis showed that the filling duration in Harbin was conducive to increased yield but the low dry weight of inferior grains was a main factor limiting the yield in Qiqihar. The average protein content values in Harbin were significantly higher (8.54% and 9.13%) than those in Qiqihar (8.34% and 9.14%) in 2017 and 2018, respectively. The amylose content was significantly higher in Harbin (20.03% and 22.27%) than those in Qiqihar (14.44% and 14.67%) in 2017 and 2018, respectively. The chalkiness percentage was higher in Qiqihar, indicating that Harbin produced good quality rice. This study provides more direct evidence of the relative changes in rice grain yield due to changes in grain-filling associated with relative changes in environmental components. These self-adaptability mechanisms to climatic variability and the inter-relationships between grain-filling and grain yield underscore the urgent to investigate and explore measures to improve Japonica rice sustainability, with better adaptation to increasing climatic variabilities. These findings may also be a reference for other global rice regions at high latitudes in addressing the impacts of climate change on future rice sustainability. [ABSTRACT FROM AUTHOR]

Rice (Oryza sativa L.) is considered as a staple food for more than half of the global population, and sustaining productivity under a scarcity of resources is challenging to meet the future food demands of the inflating global population. The aerobic rice system can be considered as a transformational replacement for traditional rice, but the widespread adaptation of this innovative approach has been challenged due to higher losses of nitrogen (N) and reduced N-use efficiency (NUE). For normal growth and developmental processes in crop plants, N is required in higher amounts. N is a mineral nutrient and an important constituent of amino acids, nucleic acids, and many photosynthetic metabolites, and hence is essential for normal plant growth and metabolism. Excessive application of N fertilizers improves aerobic rice growth and yield, but compromises economic and environmental sustainability. Irregular and uncontrolled use of N fertilizers have elevated several environmental issues linked to higher N losses in the form of nitrous oxide (N2O), ammonia (NH3), and nitrate (NO3-), thereby threatening environmental sustainability due to higher warming potential, ozone depletion capacities, and abilities to eutrophicate the water resources. Hence, enhancing NUE in aerobic rice has become an urgent need for the development of a sustainable production system. This article was designed to investigate the major challenge of low NUE and evaluate recent advances in pathways of the N cycle under the aerobic rice system, and thereby suggest the agronomic management approaches to improve NUE. The major objective of this review is about optimizing the application of N inputs while sustaining rice productivity and ensuring environmental safety. This review elaborates that different soil conditions significantly shift the N dynamics via changes in major pathways of the N cycle and comprehensively reviews the facts why N losses are high under the aerobic rice system, which factors hinder in attaining high NUE, and how it can become an eco-efficient production system through agronomic managements. Moreover, it explores the interactive mechanisms of how proper management of N cycle pathways can be accomplished via optimized N fertilizer amendments. Meanwhile, this study suggests several agricultural and agronomic approaches, such as site-specific N management, integrated nutrient management (INM), and incorporation of N fertilizers with enhanced use efficiency that may interactively improve the NUE and thereby plant N uptake in the aerobic rice system. Additionally, resource conservation practices, such as plant residue management, green manuring, improved genetic breeding, and precision farming, are essential to enhance NUE. Deep insights into the recent advances in the pathways of the N cycle under the aerobic rice system necessarily suggest the incorporation of the suggested agronomic adjustments to reduce N losses and enhance NUE while sustaining rice productivity and environmental safety. Future research on N dynamics is encouraged under the aerobic rice system focusing on the interactive evaluation of shifts among activities and diversity in microbial communities, NUE, and plant demands while applying N management measures, which is necessary for its widespread adaptation in face of the projected climate change and scarcity of resources. [ABSTRACT FROM AUTHOR]

Grain appearance is one of the most important attributes of rice. It is determined by grain size, shape, and weight, which in turn influences the rice yield and market value. In this study, QTLs for grain length, grain width, grain length/width ratio, and grain weight were mapped using the high-throughput indica/indica SNP platforms. The population of the mega indica variety IR64 and the highquality aromatic variety Sadri from Iran was phenotyped. Based on this phenotypic data, plants of 94 F2:3 families including both parents were selected. A linkage map analysis of 210 SNP markers identified 14 QTLs controlling the grain length, grain width, length/width ratio, and 1,000 grain weight. Among these 14, one important region containing the QTLs for all the four studies' traits was mapped on chromosome 8. It was derived from Sadri for the decreased length/width ratio and increased grain weight. This study demonstrated the speed and efficiency in using multiplex SNP genotyping for QTL analysis. Moreover, this study identified four novel QTLs (qGL8, qTGW8, qLWR8, and qGW8) sharing the same position on chromosome 8 which were linked with grain quality characteristics between one indica and one aromatic variety. It will enable more precise marker-assisted selection for grain weight, shape, and size. Further in-depth studies are required to dissect this region of interest and identify the related gene(s). [ABSTRACT FROM AUTHOR]

Nanotechnology is an emerging technique that helps in solving the biotic and abiotic agricultural issues leading to enhance crop productivity. Therefore, it was hypothesized to check the effect of Qiangdi 863 nano synergids biological-assisted growth apparatus and nitrogen, phosphorous, and potassium (NPK) fertilizers improving rice germination, early growth, physiology, and yield. An experiment was performed on five rice varieties for three consecutive years (2017-2019). The nanosynergids-treated water (NTW) significantly improved the speed of germination (25.3, 35.6, and 32.3%), final emergence percentage (100%) and seed emergence energy percentage (80, 95, and 90%), radical (1.25, 1.7, and 2.35 cm) and plumule growth (1.29, 1.24, and 1.66 cm), soil plant analysis development (46, 45, and 47), antioxidant enzymatic activities, such as catalase activity (34,376 mg1FW h1, 33,264 mg1FW h1, and 34,453 mg1F W h1), superoxide dismutase (18,456 m1F W h1, 19,445 mg1F W h1, and 19,954 mg1F W h1), peroxide (745 Ug1F W, 734 Ug1F W, and 752 Ug1F W), production and declined malondialdehyde (4.5 mmolg1F W, 5.1 mmolg1F W, and 4.2 mmolg1F W) for all years respectively in KSK 133. The application of nano-treated irrigated water enriched the biomass of rice seedlings. The overall nano synergid treatments successfully enhanced the endogenous hormones as salicylic acid (6,016.27 p mol/L, 5823.22 p mol/L, and 5922.12 p mol/L), jasmonates (JA) (5,175.6 p mol/L, 4231 p mol/L, and 5014.21 p mol/L) brassinosteroids (BR) (618.2 p mol/L, 546.83 p mol/L, and 582.1 p mol/L) quantification and yield 1000 grain weight (22.3, 22, and 23.2 g) of KSK 133. Hence, the overall results proved that NTW could effectively enhance the early growth and yield of rice varieties. [ABSTRACT FROM AUTHOR]

The abundance and structural composition of nitrogen (N) transformation-related microbial communities under certain environmental conditions provide sufficient information about N cycle under different soil conditions. This study aims to explore the major challenge of low N use efficiency (NUE) and N dynamics in aerobic rice systems and reveal the agronomic-adjustive measures to increase NUE through insights into the ecophysiology of ammonia oxidizers. Water-saving practices, like alternate wetting and drying (AWD), dry direct seeded rice (DDSR), wet direct seeding, and saturated soil culture (SSC), have been evaluated in lowland rice; however, only few studies have been conducted on N dynamics in aerobic rice systems. Biological ammonia oxidation is majorly conducted by two types of microorganisms, ammonia-oxidizing archaea (AOA) and ammonia-oxidizing bacteria (AOB). This review focuses on how diversified are ammonia oxidizers (AOA and AOB), whose factors affect their activities and abundance under different soil conditions. It summarizes findings on pathways of N cycle, rationalize recent research on ammonia oxidizers in N-cycle, and thereby suggests adjustive agronomic measures to reduce N losses. This review also suggests that variations in soil properties significantly impact the structural composition and abundance of ammonia oxidizers. Nitrification inhibitors (NIs) especially nitrapyrin, reduce the nitrification rate and inhibit the abundance of bacterial amoA without impacting archaeal amoA. In contrast, some NIs confine the hydrolysis of synthetic N and, therefore, keep low NH4+-N concentrations that exhibit no or very slight impact on ammonia oxidizers. Variations in soil properties are more influential in the community structure and abundance of ammonia oxidizers than application of synthetic N fertilizers and NIs. Biological nitrification inhibitors (BNIs) are natural bioactive compounds released from roots of certain plant species, such as sorghum, and could be commercialized to suppress the capacity of nitrifying soil microbes. Mixed application of synthetic and organic N fertilizers enhances NUE and plant N-uptake by reducing ammonia N losses. High salt concentration promotes community abundance while limiting the diversity of AOB and vice versa for AOA, whereas AOA have lower rate for potential nitrification than AOB, and denitrification accounts for higher N2 production. Archaeal abundance, diversity, and structural composition change along an elevation gradient and mainly depend on various soil factors, such as soil saturation, availability of NH4+, and organic matter contents. Microbial abundance and structural analyses revealed that the structural composition of AOA was not highly responsive to changes in soil conditions or N amendment. Further studies are suggested to cultivate AOA and AOB in controlled-environment experiments to understand the mechanisms of AOA and AOB under different conditions. Together, this evaluation will better facilitate the projections and interpretations of ammonia oxidizer community structural composition with provision of a strong basis to establish robust testable hypotheses on the competitiveness between AOB and AOA. Moreover, after this evaluation, managing soils agronomically for potential utilization of metabolic functions of ammonia oxidizers would be easier. [ABSTRACT FROM AUTHOR]

Transcription factors (TFs) regulate gene expression to control certain genetic programs, such as growth and development, phytohormone regulation, and environmental stresses. 2‐acetyl‐1‐pyrroline (2‐AP) is the key element involved in aroma biosynthesis pathway, and the application of micronutrients can increase the 2‐AP levels. However, little is known about the micronutrient‐induced TFs involved in 2‐AP biosynthesis. Here, we identify a number of TF families in two fragrant rice varieties, "Meixiangzhan‐2" (M) and "Xiangyaxiangzhan" (X), in response to Zinc (Zn) application through transcriptomic analysis. A total of ~678 TFs were identified and grouped into 26 TF families, each of which was found to be involved in numerous signaling pathways. The WRKY TF family was found to be the most abundant, followed by bHLH and MYB. Furthermore, members of the WRKY, bHLH, MYB, ERF, HSF, MADS‐box, NFY, and AP2 TF families were significantly upregulated and may be involved in the transcriptional regulation of aroma biosynthesis. In brief, this study enhances our understanding of the molecular mechanism of 2‐AP biosynthesis and highlights the key TFs potentially involved in the production of aroma in fragrant rice. [ABSTRACT FROM AUTHOR]

Globally, rice is being consumed as a main staple food and faces different kinds of biotic and abiotic stresses such drought, salinity, and pest attacks. Through the cytokinin signaling, Type‐B authentic response regulators (ARR‐Bs) respond positively towards the environmental stimuli. ARR‐Bs are involved in abiotic stress tolerance and plant development but their molecular mechanisms in fragrant rice are still not fully explored. The current study showed the genome‐wide characterization of OsARR‐B genes under alkaline salt stress. Results showed that in total, 24 OsARR‐B genes were found and divided into four subgroups on the basis of a phylogenetic analysis. These genes were located on all rice chromosomes except 8 and 10. Analysis of gene duplications, gene structure, cis‐elements, protein–protein interactions, and miRNA were performed. Gene ontology analysis showed that OsARR‐B genes are involved in plant development through the regulation of molecular functions, biological processes, and cellular components. Furthermore, 117 and 192 RNA editing sites were detected in chloroplast and mitochondrial genes, respectively, encoding proteins of OsARR‐B. In chloroplast and mitochondrial genes, six and nine types of amino acid changes, respectively, were caused by RNA editing, showing that RNA editing has a role in the alkaline salt stress tolerance in fragrant rice. We also used a comparative transcriptome approach to study the gene expression changes in alkaline tolerant and susceptible genotypes. Under alkaline salt stress, OsARR‐B5, OsARR‐B7, OsARR‐B9, OsARR‐B10, OsARR‐B16, OsARR‐B22, and OsARR‐B23 showed higher transcript levels in alkaline salt tolerant genotypes as compared to susceptible ones. Quantitative RT‐PCR showed upregulation of gene expression in the alkaline tolerant genotypes under alkaline stress. Our study explored the gene expression profiling and RESs of two rice contrasting genotypes, which will help to understand the molecular mechanisms of alkaline salt tolerance in fragrant rice. [ABSTRACT FROM AUTHOR]

Rice cultivation in Egypt is limited by the scarcity of water resources. The main strategy of rice breeders to overcome this problem is to develop new high-yielding varieties that are tolerant to drought stress. In this study, an drought-tolerant (IR60080-46A) variety was crossed with commercial Egyptian varieties using the back-cross method and marker-assisted selection (MAS) approach. The advanced lines of these crosses were selected under drought stress conditions. The best-performing candidate line, RBL-112, and its parental genotypes, were evaluated under drought stress and control conditions. The RBL-112 line showed superior its root system, which in turn produced higher grain yield under drought-stress conditions than its parental and check genotypes. Furthermore, physiological and biochemical studies showed that the RBL-112 line maintained higher relative water content (RWC), maximum quantum efficiency of photosystem II (Fv/Fm) values, proline content, superoxide dismutase (SOD) activity, and lower malondialdehyde (MDA) content compared to its parents and the check. The functional expression profiles of 22 drought tolerance-related genes were studied, out of which the genes OsAHL1, OsLEA3, OsCATA, OsP5CS, OsSNAC1, Os1g64660, OsRab21, OsAPX2, OsDREB2A, OsSKIPa, and OsLG3 were strongly induced in the newly developed RBL-112 line under drought-stress conditions. It could be concluded that the new line has a higher capacity to modulate physiological activities and expression levels of several drought-induced genes to withstand drought stress with high yielding ability. This finding suggests that the RBL-112 line presents a promising new addition to enable sustainable rice cultivation under water-limited conditions, and confirms the efficiency of the approach implemented in the current study. [ABSTRACT FROM AUTHOR]

Multiple stress tolerance at the seed germination stage is crucial for better crop establishment in the direct-seeded rice ecosystem. Therefore, identifying rice genes/quantitative trait loci (QTLs) associated with salinity and anaerobic tolerance at the germination stage is a prerequisite for adaptive breeding. Here, we studied 498 highly diverse rice accessions Xian (Indica) and Geng (Japonica), and six traits that are highly associated with salinity and anaerobic tolerance at germination stage were measured. A high-density 2.8M Single Nucleotide Polymorphisms (SNP) genotype map generated from the 3,000 Rice Genomes Project (3KRGP) was used for mapping through a genome-wide association study. In total, 99 loci harboring 117 QTLs were detected in different populations, 54, 21, and 42 of which were associated with anaerobic, salinity, and combined (anaerobic and salinity) stress tolerance. Nineteen QTLs were close to the reported loci for abiotic stress tolerance, whereas two regions on chromosome 4 (qSGr4a / qCL4c / qRI4d and qAGr4 / qSGr4b) and one region on chromosome 10 (qRI10/qCL10/ qSGr10b/qBM10) were associated with anaerobic and salinity related traits. Further haplotype analysis detected 25 promising candidates genes significantly associated with the target traits. Two known genes (OsMT2B and OsTPP7) significantly associated with grain yield and its related traits under saline and anaerobic stress conditions were identified. In this study, we identified the genes involved in auxin efflux (Os09g0491740) and transportation (Os01g0976100), whereas we identified multistress responses gene OsMT2B (Os01g0974200) and a major gene OsTPP7 (Os09g0369400) involved in anaerobic germination and coleoptile elongation on chromosome 9. These promising candidates provide valuable resources for validating potential salt and anaerobic tolerance genes and will facilitate direct-seeded rice breeding for salt and anaerobic tolerance through marker-assisted selection or gene editing. [ABSTRACT FROM AUTHOR]

Transcription factors are regulatory proteins known to modulate gene expression. These are the critical component of signaling pathways and help in mitigating various developmental and stress responses. Among them, bZIP, BBR, and BZR transcription factor families are well known to play a crucial role in regulating growth, development, and defense responses. However, limited data is available on these transcription factors in Triticum aestivum. In this study, bZIP, BBR, and BZR sequences from Brachypodium distachyon, Oryza sativa, Oryza barthii, Oryza brachyantha, T. aestivum, Triticum urartu, Sorghum bicolor, Zea mays were retrieved, and dendrograms were constructed to analyze the evolutionary relatedness among them. The sequences clustered into one group indicated a degree of evolutionary correlation highlighting the common lineage of cereal grains. This analysis also exhibited that these genes were highly conserved among studied monocots emphasizing their common ancestry. Furthermore, these transcription factor genes were evaluated for envisaging conserved motifs, gene structure, and subcellular localization in T. aestivum. This comprehensive computational analysis has provided an insight into transcription factor evolution that can also be useful in developing approaches for future functional characterization of these genes in T. aestivum. Furthermore, the data generated can be beneficial in future for genetic manipulation of economically important plants. [ABSTRACT FROM AUTHOR]

Fourteen rice lines and one cultivar were investigated for morphological traits and genetic diversity under normal and drought stress condition. Mean squares of years, environment and lines × environments were significant for all traits under observation, except for days to heading and grain yield/plant in years, days to heading in environment and days to heading and harvest index in lines × environments, respectively. The 10 SSR markers, covering seven chromosomes (1, 2, 4, 5, 6, 8 and 9) generated polymorphic alleles with sum of 72 alleles on seven chromosomes with 9 markers across the fifteen rice lines. Furthermore, genetic diversity values for all SSR markers varied from 0.94 to 1.00 with an average of 0.98. In addition, the PIC values ranged from 0.83 to 0.99 with an average value of 0.94. The promising lines of present investigation can be utilized in future plant breeding programs. [ABSTRACT FROM AUTHOR]

The growth, development, and quality of rice are inhibited by the presence of cadmium (Cd) in the soil, the uptake of which depends strongly on the pH of the growth medium. Here, a hydroponics-based experiment was conducted to characterize the relationship between Cd accumulation and the pH of the medium in seedlings of the two cultivars, Zhonjiazao17 (ZJZ17) and Xiangzhengyu (XZY). The uptakes of Cd by the roots of both cultivars and its translocation to the shoots were the highest from a medium of pH 6.0. XZY plants accumulated more Cd than ZJZ17 ones. Transcription profiling indicated that the genes, OsNRAMP1 and OsHMA2, were actively involved in Cd uptake and transport, as they were both strongly upregulated at pH 6.0. Both the Cd concentration of the medium and its pH exerted significant effects on the seedling growth. At pH 6.0, zinc was efficiently transported, but the translocation of iron was suppressed in shoot. The genes, OsZIP5 and OsYSL15, are the most likely responsible for the uptake and translocation of both these elements in rice seedlings. [ABSTRACT FROM AUTHOR]

• Rice is one of the important cereals and staple food for more than half of the world. Climate change and diminishing resources are the major challenges in the sustainable rice production. • Aerobic rice system can be a transformational approach to replace conventional rice in face of climate change and scarcity of resources due to its high input-use efficiency. • Aerobic rice crop failure can be reduced if availability of suitable and stress resistant cultivars with early improved vigour, and short-duration characteristics is ensured for maintaining the reproductive capability under resource stressed environment. • Several constraints are associated with the shift from flooded to aerobic rice brings changes in crop water demand, organic matter (OM) turnover, N dynamics, weed flora, and greenhouse gases (GHGs) emissions. Along with N-losses, continuous monocropping, higher weed infestation, weedy rice emergence, nitrous oxide (N 2 O) emissions, nutrient disorders, higher prevalence of pathogens and diseases, increased panicle sterility, and an increase in soilborne pathogens lodging are other major constraints negatively impacting the widespread adaptation of aerobic rice. • This article reviews the climate change status, its associated impacts on the sustainability of traditional rice system, and the rationale for transforming from traditional to aerobic rice system. • Furthermore, it described the major constraints and challenges associated in the wider adaptation of the new approach for sustainable rice production under in face of projected climate change and scarcity of resources. • Lastly, this article highlights the potential management measures to reduce the associated risks in aerobic rice system. Climate change and diminishing resources are the major challenges in sustainable rice production. The aerobic rice system can be a transformational approach to replace conventional rice in the face of climate change and scarcity of resources due to its high input-use efficiency. However, it could not be adapted widely yet due to several challenges like higher weed infestation and low nitrogen (N) use efficiencies. This transformed system can only be adapted at a wider scale through investigation of associated constraints and risks and provision of potential adjustive measures. Aerobic rice crop failure can be reduced if the availability of suitable and stress-resistant cultivars with early improved vigour, and short-duration characteristics are ensured for maintaining the reproductive capability under resource stressed environment. This transformed rice system exhibits limited response to applied N because of increased losses due to higher volatilization and rapid coupled nitrification-denitrification processes under alternate wetting and drying systems. Shifting from the flooded to aerobic rice system bringing changes in crop water demand, organic matter (OM) turnover, N dynamics, weed flora, and greenhouse gases (GHGs) emissions. Along with N-losses, continuous monocropping, higher weed infestation, weedy rice emergence, nitrous oxide (N 2 O) emissions, nutrient disorders, higher prevalence of pathogens and diseases, increased panicle sterility, and an increase in soilborne pathogens lodging are other major constraints negatively impacting the widespread adaptation of aerobic rice. This article reviews the climate change status, its associated impacts on the sustainability of traditional rice systems, and the rationale for transforming from traditional to aerobic rice systems. Furthermore, it describes the major challenges associated with the aerobic rice system, thereby presenting management strategies ensuring its wider adaptation for sustainable rice production in the face of projected climate change and scarcity of resources. [ABSTRACT FROM AUTHOR]

The salt stress affects plant growth and physiological characteristics during early growth stages in rice (Oryza sativa L.) The objective of this study was to examine the influence of salt stress on rice growth during early stages and to find out their salt tolerance levels. A pot culture experiment was conducted in rice cropping season 2016, with completely randomized design (CRD) and three replicates. The treatments were two rice cultivars, 'Liangyoupeijiu' (LYP9) and 'Nipponbare' (NPBA) with four salt stress levels 0 (control, CK), 1.5 (low salt stress, LS), 4.5 (medium salt stress, MS), and 7.5 g (heavy salt stress, HS) NaCl kg-1 soil at different growth stages with six seedlings per pot. About 15 parameters were recorded and most of the treatments were significantly different (P ≤ 0.05) from each other. The results showed that salt stress reduced seed emergence characteristics of the rice. It also decreased photosynthetic parameters, growth characteristics including DM, and seedling height reduction increased at early seedling and maximum tillering stage in both rice cultivars but this disaster is less in 'LYP9' than 'NPBA'. On the basis of DM reduction, 'LYP9' was categorized as moderately susceptible (MS) and susceptible (S) at HS during early growth stage, and 'NPBA' was categorized as sensitive to the HS stress level. The result suggested that 'LYP9' showed somehow resistance under salt stress than 'NPBA'. This study will help us to provide new ideas for improving the high yielding rice cultivar (LYP9) to salt tolerance by genetic modification and cultivation techniques. [ABSTRACT FROM AUTHOR]