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28 January 2020, Volume 27 Issue 1 Previous Issue    Next Issue
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Cellular Localization of Rice SUMO/SUMO Conjugates and in vitro Sumoylation Using Rice Components Joo Joungsu, Hee Choi Dong, Hyon Kim Sang, Ik Song Sang 2020, 27(1): 1-4.  DOI: 10.1016/j.rsci.2019.02.003 Abstract ( )   HTML ( )   PDF (924KB) ( )

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Drought Stress Impairs Grain Yield and Quality of Rice Genotypes by Impaired Photosynthetic Attributes and K Nutrition Zahid Mumtaz Muhammad, Saqib Muhammad, Abbas Ghulam, Akhtar Javaid, Ul-Qamar Zia 2020, 27(1): 5-9.  DOI: 10.1016/j.rsci.2019.12.001 Abstract ( )   HTML ( )   PDF (489KB) ( )

Research Paper

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Differential Expression of Rice Valine-Qlutamine Gene Family in Response to Nitric Oxide and Regulatory Circuit of OsVQ7 and OsWRKY24 Xixu Peng, Ting Xiao, Jiao Meng, Zong Tao, Dinggang Zhou, Xinke Tang, Haihua Wang 2020, 27(1): 10-20.  DOI: 10.1016/j.rsci.2019.12.002 Abstract ( )   HTML ( )   PDF (857KB) ( )   The functional diversity of plant valine-qlutamine (VQ) proteins is closely associated with their partners WRKY transcription factors, and also with a complex network of signaling pathways that mediated by hormone molecules. We reported genome-wide expression profiles of differentially expressed rice VQ genes under nitric oxide (NO) treatment based on a microarray analysis. Cluster analysis of expression patterns revealed that some VQ genes and WRKY genes shared similar expression trends. Prediction of cis-elements showed that W-box or W-box-like sequences were overrepresented within the promoters of most of NO-responsive VQ genes. In particular, the similarly expressed OsVQ7 and OsWRKY24 showed great induction upon NO triggering. Transient expression assay and chromatin immunoprecipitation analysis demonstrated that OsWRKY24 was specifically bound to the promoter regions of OsVQ7 and OsWRKY24 itself, which contain multiple copies of W-box or W-box-like cis-elements. Yeast-two-hybrid assay indicated that OsWRKY24 can interact physically with OsVQ7 through the C-terminal of WRKY domain. The results suggested that OsVQ7 and OsWRKY24 may form an auto- and cross-regulation circuit that is required for tight regulation and fine-tuning of physiological processes they are involved in. These findings provided a solid foundation for exploring the specific functions of the VQ protein family in NO signaling pathway.

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Systematic Characterization of Long Non-Coding RNAs and Their Responses to Drought Stress in Dongxiang Wild Rice Weidong Qi, Hongping Chen, Zuozhen Yang, Biaolin Hu, Xiangdong Luo, Bing Ai, Yuan Luo, Yu Huang, Jiankun Xie, Fantao Zhang 2020, 27(1): 21-31.  DOI: 10.1016/j.rsci.2019.12.003 Abstract ( )   HTML ( )   PDF (969KB) ( )   Long non-coding RNAs (lncRNAs) play important roles in response to various biotic and abiotic stresses. So far, systematic identification and characterization of lncRNAs have been reported in a few model plant species and major crops, but their roles in abiotic stress response have not yet been reported in common wild rice (Oryza rufipogon). Dongxiang wild rice (DXWR) possesses a high degree of drought resistance and has been well recognized as a precious genetic resource for drought resistant rice breeding. We presented the reference catalog of 1 655 novel lncRNA transcripts in DXWR using strand-specific RNA sequencing and bioinformatics approaches. Meanwhile, a total of 1 092 lncRNAs were determined as differentially expressed lncRNAs under drought stress. Quantitative real-time PCR results exhibited a high concordance with RNA sequencing data, which confirmed that the expression patterns of lncRNAs based on RNA sequencing were highly reliable. Furthermore, 8 711 transcripts were predicted as target genes of the differentially expressed lncRNAs. Functional annotation analysis based on Gene Ontology and Kyoto Encyclopedia of Genes and Genomes databases showed that the target genes were significantly enriched in cellular and metabolic processes, cell part, binding and plant hormone signal transduction, as well as many other terms related to abiotic stress resistance. These results expanded our understanding of lncRNA biology and provided candidate regulators for genetic improvement of drought resistance in rice cultivars.

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Assessment of Variation in Morpho-Physiological Traits and Genetic Diversity in Relation to Submergence Tolerance of Five Indigenous Lowland Rice Landraces Barik Jijnasa, Kumar Vajinder, K. Lenka Sangram, Panda Debabrata 2020, 27(1): 32-43.  DOI: 10.1016/j.rsci.2019.12.004 Abstract ( )   HTML ( )   PDF (988KB) ( )   The present study evaluated submergence responses in 88 lowland indigenous rice (Oryza sativa L.) landraces from Koraput, India, to identify submergence-tolerant rice genotypes. In pot experiments, variations in survival rate, shoot elongation, relative growth index, dry matter, chlorophyll, soluble sugar and starch contents were evaluated in two consecutive years under well-drained and completely submerged conditions. Principal component analysis showed that the first three axes contributed 96.820% of the total variation among the landraces, indicating wide variation between genotypes. Major traits such as survival rate, relative growth index, soluble sugar and starch contents appeared to be important determinants of phenotypic diversity among the landraces. Phenotypic coefficient of variance was higher than genotypic coefficient of variance for all the traits and all showed high heritability (90.38%-99.54%). Five rice landraces (Samudrabali, Basnamundi, Gadaba, Surudaka and Dokarakuji) were the most tolerant to submergence. When submerged for up to 14 d, Samudrabali, Basnamundi and Godoba were notable for having greater survival rates than a standard submergence tolerant variety FR13A, and also notable for elongating more vigorously and accumulating more biomass. These three landraces may therefore be especially useful in lowland rice growing areas that are affected by both moderate stagnant water and flash flooding. Molecular genotyping revealed that the submergence tolerance of Samudrabali, Basnamundi and Godoba is linked to the presence of one or more different Sub1 loci and it may well prove useful for breeding improved submergence tolerant rice varieties, thereby assising to improve yield stability in the rainfed lowland agro-ecosystem.

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Decrement of Sugar Consumption in Rice Young Panicle Under High Temperature Aggravates Spikelet Number Reduction Yaliang Wang, Yikai Zhang, Qinghua Shi, Huizhe Chen, Jing Xiang, Guohui Hu, Yanhua Chen, Xiaodan Wang, Junke Wang, Zihao Yi, Defeng Zhu, Yuping Zhang 2020, 27(1): 44-55.  DOI: 10.1016/j.rsci.2019.12.005 Abstract ( )   HTML ( )   PDF (1463KB) ( )   Two rice genotypes Huanghuazhan (HHZ, heat-resistant) and IR36 (heat-susceptible) were subjected to high-temperature (HT, 40 ºC) and normal-temperature (NT, 32 ºC) treatments at the spikelet differentiation stage. HT treatment inhibited spikelet differentiation, aggravated spikelet degeneration, reduced spikelet size, and disordered carbohydrate allocation. Meanwhile, HT treatment increased nonstructural carbohydrate content in leaves, but decreased that in stems and young panicles, and the same tendencies of sucrose and starch contents were observed in leaves and stem. However, HT treatment significantly increased the sucrose content and sharply decreased the glucose and fructose contents in young panicles. Lower activity levels of soluble acid invertase (EC3.2.1.26) and sucrose synthase (EC2.4.1.13) were observed under HT treatment. Moreover, HT treatment reduced the activities of key enzymes associated with glycolysis and the tricarboxylic acid cycle, which indicated sucrose consumption was inhibited in young panicles under HT treatment. Exogenous glucose and fructose applied under HT treatment increased the spikelet number more than exogenous sucrose. In conclusion, the results demonstrated that the reduction of spikelet number under high temperature was more affected by the decrease in sugar consumption than the blocking of sucrose transport. The impairment of sucrose hydrolysis was the main reason for the inhibition of sugar utilization.

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Adoption and Impact of Modern Rice Varieties on Poverty in Eastern India Kwasi Bannor Richard, Amarnath Krishna Kumar Gupta, Oppong-Kyeremeh Helena, Abawiera Wongnaa Camillus 2020, 27(1): 56-66.  DOI: 10.1016/j.rsci.2019.12.006 Abstract ( )   HTML ( )   PDF (720KB) ( )   The factors affecting the adoption of modern varieties (MVs) of rice and impact on poverty in Odisha, India were discussed. A total of 363 households from Cuttack and Sambalpur districts of Odisha via multistage sampling technique participated in the survey. The Cragg’s Double hurdle model was used to model the determinants of adoption and intensity of adoption of MVs of rice, and the propensity score matching was used to analyze the impact of adoption on poverty. The results showed that age, education, risk aversion, land size, yield, perception of MVs as high yielding, resistant to diseases and availability of MVs positively influenced the decision to adopt. However, variables such as household size, experience of a farmer, off-farm job participation, amount of credit received, cost of seeds, insecticides and fertilizers negatively influenced the adoption of MVs. Intensity of adoption of MVs was negatively influenced by experience of a farmer, cost of fertilizer and marketability of MVs, and positively affected by household size, risk aversion, land size, cost of insecticides, perception of MVs as high yielding and availability of MV seeds. Poverty incidence, gap and severity were high among non-adopters to adopters of MVs. After matching adopters and non-adopters of MV groups using four different algorithms of nearest neighbour matching, stratification matching, radius matching and kernel matching, the impact of MV adoption resulted in higher per capita monthly household expenditure by about US$ 52.82 to US$ 63.17.

Short Communication

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Morpho-Physiological Response of Oryza glaberrima to Gradual Soil Drying Kartika Kartika, Sakagami Jun-Ichi, Lakitan Benyamin, Yabuta Shin, Wijaya Andi, Kadir Sabaruddin, Ilman Widuri Laily, Siaga Erna, Nakao Yoshihiro 2020, 27(1): 67-74.  DOI: 10.1016/j.rsci.2019.12.007 Abstract ( )   HTML ( )   PDF (800KB) ( )   Soil drought occurrence during dry season has been the main constraint, besides prolonged flooding during rainy season, in increasing cropping intensity and rice productivity in tropical riparian wetland. Use of drought tolerant rice genotype might be a suitable option for overcoming such problem. This study focused on the effects of gradual soil drying during early vegetative growth stage on morphological and physiological traits of five Oryza glaberrima genotypes, namely RAM12, RAM14, RAM59, RAM97 and RAM101, and two Oryza sativa subsp japonica genotypes, i.e. Koshihikari and Minamihatamochi. The plants were subjected to 6 d of gradual soil drying condition from 15 days after transplanting (DAT) to 20 DAT, and were allowed to recover until 22 DAT. Gradual soil drying reduced plant growth as indicated by dry mass accumulation. Drought reduced stomatal conductance and increased leaf rolling score of all the genotypes. All the genotypes showed comparable response on stomatal conductance, but O. glaberrima genotypes performed higher in leaf rolling recovery. Meanwhile, O. sativa genotypes decreased total leaf area and specific leaf area, but increased specific leaf weight in order to avoid further damages due to drought stress. Drought tolerance mechanisms in RAM101, RAM12, RAM59 and RAM14 were associated with leaf morpho-physiological responses, root traits and dry biomass accumulation.

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Optimization of High-Protein Glutinous Rice Flour Production Using Response Surface Method Eakkanaluksamee Kanjanapa, Anuntagool Jirarat 2020, 27(1): 75-80.  DOI: 10.1016/j.rsci.2019.12.008 Abstract ( )   HTML ( )   PDF (1245KB) ( )   A response surface method was employed to study the effect of α-amylase concentration, hydrolysis temperature and time on the production of high protein glutinous rice flour (HPGRF). The suspension of glutinous rice flour (15%) that contained 6.52% protein was gelatinized and subsequently hydrolyzed by thermostable α-amylase. The hydrolysis yielded 0.144-0.222 g/g HPGRF with 29.4%-45.4% protein content. Hydrolysis time exerted a significant effect, while enzyme concentration and hydrolysis temperature showed insignificant effect on the protein content and production yield of HPGRF. The result of response surface method showed that the optimum condition for the production of HPGRF that contained at least 36% protein was treating gelatinized 15% glutinous rice flour suspension with 0.90 Kilo Novo α-amylase Unit (KNU)/g α-amylase at 80 ºC for 99 min. By carrying out the predicted hydrolysis condition, HPGRF with 35.9% protein and 61.8% carbohydrates was resulted. The process yielded 0.172 g/g HPGRF. HPGRF contained higher amount of essential amino acids compared to glutinous rice flour. HPGRF had higher solubility and lower swelling power, and also showed no pasting peak compared with glutinous rice flour.