How Rice Plants Response to Abiotic Stresses

With the combustion of fossil fuels, unequal and unsustainable energy and land use, and irrational human activities, greenhouse gas emissions remain high, which leads to global warming [...

A New Energy-efficient Multi-target Coverage Control Protocol Using Event-driven-mechanism in Wireless Sensor Networks

The covering problem and node deployment is a fundamental problem in the research into wireless sensor networks. The number of nodes and the coverage of a network can directly affect performance and operating costs. For this reason, we propose Event-driven-mechanism Coverage Control Protocol (ECCP). The algorithm uses the correlation between the nodes and dynamic grouping to adjust the coverage area. Within the coverage area, we use the greedy algorithm to optimize the coverage area. So the target node is uniformly covered by other sensor nodes and the network resource is optimized. To ensure the energy balance in the wireless sensor network and extend its lifetime, we only wake partial nodes to work in a cycle, so that they can work in turn. Experiments show that the algorithm can effectively reduce energy consumption, with better adaptability and effectiveness

Comparative Transcriptome Analysis Reveals <i>OsBGs</i> and <i>OsGSLs</i> Influence Sugar Transport through Callose Metabolism under Heat Stress in Rice

Heat or high temperature stress have caused huge damage to many crops and have become the largest threat in terms of the future. Although a huge amount of research has been conducted to explore the mechanisms of heat tolerance and many achievements were accomplished, the mechanism by which how heat stress (HS) influences the yield is still unclear. In this study, RNA-seq analysis indicated that nine 1,3-β-glucanases (BGs) belonging to the carbohydrate metabolic pathway were expressed differently during heat treatment. Therefore, we identified the BGs and glucan-synthase-likes (GSLs) in three rice ecotypes and processed the analyses of gene gain and loss, phylogenetic relationship, duplication, and syntenic relationship. We found the possibility of an environmental adaption based on BGs and GSLs during evolution. Submicrostructure and dry matter distribution analysis confirmed that HS might block the endoplasmic sugar transport pathway by increasing callose synthesis, which may lead to decreased yield and quality in rice production. This study provides a new clue regarding rice yield and quality under HS and provides guidance to rice cultivation and heat tolerance breeding

Differential responses of CO2 assimilation, carbohydrate allocation and gene expression to NaCl stress in perennial ryegrass with different salt tolerance.

Little is known about the effects of NaCl stress on perennial ryegrass (Lolium perenne L.) photosynthesis and carbohydrate flux. The objective of this study was to understand the carbohydrate metabolism and identify the gene expression affected by salinity stress. Seventy-four days old seedlings of two perennial ryegrass accessions (salt-sensitive 'PI 538976' and salt-tolerant 'Overdrive') were subjected to three levels of salinity stress for 5 days. Turf quality in all tissues (leaves, stems and roots) of both grass accessions negatively and significantly correlated with GFS (Glu+Fru+Suc) content, except for 'Overdrive' stems. Relative growth rate (RGR) in leaves negatively and significantly correlated with GFS content in 'Overdrive' (P0.05 for turf quality). A greater up-regulation in the expression of SPS, SS, SI, 6-SFT gene was observed in 'Overdrive' than 'PI 538976'. A higher level of SPS and SS expression in leaves was found in 'PI 538976' relative to 'Overdrive'. Accumulation of hexoses in roots, stems and leaves can induce a feedback repression to photosynthesis in salt-stressed perennial ryegrass and the salt tolerance may be changed with the carbohydrate allocation in leaves and stems

Strengthened Assimilate Transport Improves Yield and Quality of Super Rice

Rice varieties with ultra-high yields play an important role in grain production and global food security. However, little information is available on the source&ndash;sink relationships that underpin the grain quality and ultra-high-yield properties. Photosynthesis, carbohydrate accumulation and allocation, vascular bundle morphology, and nutrient uptake and characteristics were, therefore, compared in two &lsquo;super rice&rsquo; varieties: Yongyou9 (control) and Yongyou12 (ultra-high yield) that differ in grain production. Yongyou12 had a significantly higher (18.8&ndash;21.4%) grain yield than Yongyou9, together with a substantial improvement in appearance-related qualities. The total dry weight and the ratio of panicle dry weight to total dry weight were significantly higher in Yongyou12 than Yongyou9, suggesting that the improved seed traits were related to higher assimilate accumulation and allocation in the ultra-high-yield variety. Yongyou12 had larger vascular bundles and greater numbers of vascular bundles in the panicle-neck internode, as well as higher levels of SUT1, SUT2, and CIN2 transcripts in the grains than Yongyou9. The contents of nitrogen, phosphorous, and potassium were similar in Yongyou12 and Yongyou9. We concluded that assimilate transport and nutrient utilization efficiency are the main factors underlying the higher yield and quality traits of the super rice variety Yongyou12

Salicylic acid reverses pollen abortion of rice caused by heat stress

Abstract Background Extremely high temperatures are becoming an increasingly severe threat to crop yields. It is well documented that salicylic acid (SA) can enhance the stress tolerance of plants; however, its effect on the reproductive organs of rice plants has not been described before. To investigate the mechanism underlying the SA-mediated alleviation of the heat stress damage to rice pollen viability, a susceptible cultivar (Changyou1) was treated with SA at the pollen mother cell (PMC) meiosis stage and then subjected to heat stress of 40 °C for 10 d until 1d before flowering. Results Under control conditions, no significant difference was found in pollen viability and seed-setting rate in SA treatments. However, under heat stress conditions, SA decreased the accumulation of reactive oxygen species (ROS) in anthers to prevent tapetum programmed cell death (PCD) and degradation. The genes related to tapetum development, such as EAT1 (Eternal Tapetum 1), MIL2 (Microsporeless 2), and DTM1 (Defective Tapetum and Meiocytese 1), were found to be involved in this process. When rice plants were exogenously sprayed with SA or paclobutrazol (PAC, a SA inhibitor) + H2O2 under heat stress, a significantly higher pollen viability was found compared to plants sprayed with H2O, PAC, or SA + dimethylthiourea (DMTU, an H2O2 and OH· scavenger). Additionally, a sharp increase in H2O2 was observed in the SA or PAC+ H2O2 treatment groups compared to other treatments. Conclusion We suggest that H2O2 may play an important role in mediating SA to prevent pollen abortion caused by heat stress through inhibiting the tapetum PCD

Strengthened Assimilate Transport Improves Yield and Quality of Super Rice

Rice varieties with ultra-high yields play an important role in grain production and global food security. However, little information is available on the source–sink relationships that underpin the grain quality and ultra-high-yield properties. Photosynthesis, carbohydrate accumulation and allocation, vascular bundle morphology, and nutrient uptake and characteristics were, therefore, compared in two ‘super rice’ varieties: Yongyou9 (control) and Yongyou12 (ultra-high yield) that differ in grain production. Yongyou12 had a significantly higher (18.8–21.4%) grain yield than Yongyou9, together with a substantial improvement in appearance-related qualities. The total dry weight and the ratio of panicle dry weight to total dry weight were significantly higher in Yongyou12 than Yongyou9, suggesting that the improved seed traits were related to higher assimilate accumulation and allocation in the ultra-high-yield variety. Yongyou12 had larger vascular bundles and greater numbers of vascular bundles in the panicle-neck internode, as well as higher levels of SUT1, SUT2, and CIN2 transcripts in the grains than Yongyou9. The contents of nitrogen, phosphorous, and potassium were similar in Yongyou12 and Yongyou9. We concluded that assimilate transport and nutrient utilization efficiency are the main factors underlying the higher yield and quality traits of the super rice variety Yongyou12

Abscisic Acid Improves Rice Thermo-Tolerance by Affecting Trehalose Metabolism

Heat stress that occurs during the flowering stage severely decreases the rice (Oryza sativa L.) seed-setting rate. This damage can be reversed by abscisic acid (ABA), through effects on reactive oxygen species, carbohydrate metabolism, and heat shock proteins, but the exact role of trehalose and ATP in this process remains unclear. Two rice genotypes, namely, Zhefu802 (heat-resistant plant, a recurrent parent) and its near-isogenic line (faded green leaf, Fgl, heat-sensitive plant), were subjected to 38 &deg;C heat stress after being sprayed with ABA or its biosynthetic inhibitor, fluridone (Flu), at the flowering stage. The results showed that exogenous ABA significantly increased the seed-setting rate of rice under heat stress, by 14.31 and 22.40% in Zhefu802 and Fgl, respectively, when compared with the H2O treatment. Similarly, exogenous ABA increased trehalose content, key enzyme activities of trehalose metabolism, ATP content, and F1Fo-ATPase activity. Importantly, the opposite results were observed in plants treated with Flu. Therefore, ABA may improve rice thermo-tolerance by affecting trehalose metabolism and ATP consumption