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28 September 2020, Volume 27 Issue 5 Previous Issue    Next Issue
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OsHG3 Affects Rice Palea Development, Grain Yield and Quality Linjuan Ouyang, Minyu Xu, Jiang Hu, Lixin Zhu, Ting Li, Yilei Xu, Changlan Zhu, Xiaosong Peng, Xiaorong Chen, Haohua He, Jie Xu 2020, 27(5): 355-358.  DOI: 10.1016/j.rsci.2019.08.008 Abstract ( )   HTML ( )   PDF (633KB) ( )

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Identification and Evaluation of UV-Tolerant Streptomyces araujoniae Strain Isolated from Tibet Plateau Soil as Biocontrol Agent Against Rice Blast Lianmeng Liu, Yuan Zhao, Jiying Lu, Mengqi Liang, Lei Sun, Jian Gao, Ling Wang, Yuxuan Hou, Shiwen Huang 2020, 27(5): 359-362.  DOI: 10.1016/j.rsci.2020.03.001 Abstract ( )   HTML ( )   PDF (598KB) ( )

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Effect of Rice Breeding Process on Improvement of Yield and Quality in China Cheng Fei, Quan Xu, Zhengjin Xu, Wenfu Chen 2020, 27(5): 363-367.  DOI: 10.1016/j.rsci.2019.12.009 Abstract ( )   HTML ( )   PDF (714KB) ( )

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Salt Tolerance Mechanisms and Approaches: Future Scope of Halotolerant Genes and Rice Landraces Bhatt Tarun, Sharma Aditi, Puri Sanjeev, Priya Minhas Anu 2020, 27(5): 368-383.  DOI: 10.1016/j.rsci.2020.03.002 Abstract ( )   HTML ( )   PDF (900KB) ( )   All rice plant developmental stages are severely affected by soil salinity. Salinity-induced ionic and osmotic stresses affect stomata closure and gaseous exchange, and reduce transpiration and the rate of carbon assimilation, and hence decrease plant yield. Understanding the response of rice plants toward salinity stress at the genetic level and developing salt-tolerant varieties are the vital mandates for its effective management. This review described the present status of salt-tolerance achieved in rice by various mechanisms including the ion homeostasis (Na+/H+, OsNHX antiporters), compatible organic solutes (glycine betaine and proline), antioxidative genes (OsECS, OsVTE1, OsAPX and OsMSRA4.1), salt responsive regulatory elements (transcription factors, cis-acting elements and miRNAs) and genes ecoding protein kinases (MAPKs, SAPKs and STRKs). Further, the future perspective of developing salt-tolerant varieties lies in exploring halotolerant gene homologs from rice varieties, especially the landraces. Genetic diversity among rice landraces can serve as a valuable resource for future studies toward variety improvement through breeding and genome editing. Further, identification, multiplication, preservation and utilization of biodiversity among landraces are the urgent buffers to be saved as a heritage for future generations to come.

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Roles of lncRNAs in Rice: Advances and Challenges Caixia Gao, Xiuwen Zheng, Hubo Li, Ali Mlekwa Ussi, Yu Gao, Jie Xiong 2020, 27(5): 384-395.  DOI: 10.1016/j.rsci.2020.03.003 Abstract ( )   HTML ( )   PDF (768KB) ( )   Long non-coding RNAs (lncRNAs) larger than 200 nucleotides in length are eukaryotic RNAs, and do not encode proteins. lncRNAs are considered to be important regulators in many biological processes in plants. In this review, the latest advances in the roles of lncRNAs in rice were reviewed, and functions of lncRNAs were further summarized and classified. lncRNAs play crucial roles in tolerance to biotic and abiotic stresses such as disease, drought, heat, cold, heavy metal, and starvation of nitrogen and phosphorus in rice. In addition, lncRNAs also regulate various growth and development processes in rice. Finally, the prospect and challenges of rice lncRNA function research in future were proposed. This review will not only help us quickly grasp the frontiers of lncRNAs functional research progresses, but also propose suggestions and ideas for the directions of further lncRNA research in rice.

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A Fragment Substitution in Promoter of MS92/PTC1 Causes Male Sterility in Rice Peng Qin, Luchang Deng, Weilan Chen, Juan Huang, Shijun Fan, Bin Tu, Jun Tan, Hua Yuan, Yuping Wang, Bingtian Ma, Shigui Li 2020, 27(5): 396-404.  DOI: 10.1016/j.rsci.2020.03.004 Abstract ( )   HTML ( )   PDF (1194KB) ( )   Persistent tapetal cell1 (PTC1) plays a curial role in pollen development, and is thought to function as a transcriptional activator in rice. However, the molecular mechanism of PTC1 in regulating pollen development and its cis-elements are not well understood. We identified a novel weak male sterility mutant (ms92) which exhibited expanded tapetum and shrink pollen grains. Map-based cloning and allelic analysis suggested that the male sterility of ms92 was caused by a DNA fragment substitution in the promoter of PTC1. The decreased expression of MS92/PTC1 in ms92 and cis-element analysis indicated that the substituted sequence contained several potential binding cis-element of negative feedback. MS92/PTC1 was specifically expressed in tapetum and microspores at the young microspore stage, and its protein was localized in nucleus. We further found that MS92/PTC1 functions as a transcription activator by recognizing H3K4me3. Transcriptomic analysis revealed that a number of genes involved in tapetum degeneration and pollen wall formation were down-regulated in ms92, which are the potential targets of MS92/PTC1. The substitution fragment in MS92/PTC1 promoter was essential for pollen development, and we provided a novel mutant for further identifying the cis-elements in promoter and the molecular network of MS92/PTC1.

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Effects of GS3 and GL3.1 for Grain Size Editing by CRISPR/Cas9 in Rice Yuyu Chen, Aike Zhu, Pao Xue, Xiaoxia Wen, Yongrun Cao, Beifang Wang, Yue Zhang, Liaqat Shah, Shihua Cheng, Liyong Cao, Yingxin Zhang 2020, 27(5): 405-413.  DOI: 10.1016/j.rsci.2019.12.010 Abstract ( )   HTML ( )   PDF (779KB) ( )   Grain size is one of key agronomic traits associated with grain yield and grain quality. Both major quantitative trait loci GS3 and GL3.1 play a predominant role in negative regulation of grain size. In this study, a CRISPR/Cas9-mediated multiplex genome editing system was used to simultaneously edit GS3 and GL3.1 in a typical japonica rice Nipponbare. In T1 generation, we found that gs3 formed slender grain with lower chalkiness percentage, while gs3gl3.1 produced larger grain with higher chalkiness percentage. In terms of other agronomic traits, flag leaf size, grain number and grain yield of both gs3 and gs3gl3.1 mutants were affected. It is noteworthy that gs3 and gs3gl3.1 mutants both led to dramatical reduction of grain number, thereby decreased grain yield. In conclusion, these results indicated that knockout of GS3 and GL3.1 could rapidly improve grain size, but probably have some negative influences on grain quality and grain yield.

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Identification of Rice QTLs for Important Agronomic Traits with Long-Kernel CSSL-Z741 and Three SSSLs Hui Wang, Jiayu Zhang, Farkhanda Naz, Juan Li, Shuangfei Sun, Guanghua He, Ting Zhang, Yinghua Ling, Fangming Zhao 2020, 27(5): 414-422.  DOI: 10.1016/j.rsci.2020.04.008 Abstract ( )   HTML ( )   PDF (1068KB) ( )   Rice kernel shape affects kernel quality (appearance) and yield (1000-kernel weight) and therefore is an important agronomic trait, but its inheritance is complicated. We identified a long-kernel rice chromosome segment substitution line (CSSL), Z741, derived from Nipponbare as a recipient and Xihui 18 as a donor parent. Z741 has six substitution segments distributed on rice chromosomes 3, 6, 7, 8 and 12 with an average replacement length of 5.82 Mb. Analysis of a secondary F2 population from a cross between Nipponbare and Z741 identified 20 QTLs for important agronomic traits. The kernel length of Z741 is controlled by a major QTL (qKL3) and a minor QTL (qKL7). Candidate gene prediction and sequencing indicated that qKL3 may be an allele of OsPPKL1, which encodes a protein phosphatase implicated in brassinosteroid signaling, and qKL7 is an unreported QTL. Finally, we validated eight QTLs (qKL3, qKL7, qRLW3-1, qRLW7, qPH3-1, qKWT3, qKWT7 and qNPB6) using three selected single- segment substitution lines (SSSLs), S1, S2 and S3. Also, we detected five QTLs (qKL6, qKW3, qKW7, qKW6 and qRLW6) in S1, S2 and S3, which were not found in the Nipponbare/Z741 F2 population. However, qNPB3, qNPB7 and qPL3 QTLs were not validated by the three SSSLs in 2019, suggesting that minor QTLs are susceptible to environmental factors. These results lay the foundation for studying the biodiversity of kernal length and molecular breeding of different kernel types.

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Effects of Space Flight on Expression of Key Proteins in Rice Leaves Deyong Zeng, Jie Cui, Yishu Yin, Meng Zhang, Shan Shan, Xin Gao, Yingchun Zhang, Yeqing Sun, Weihong Lu 2020, 27(5): 423-433.  DOI: 10.1016/j.rsci.2019.12.011 Abstract ( )   HTML ( )   PDF (1143KB) ( )   As a unique form of abiotic stress, the environmental conditions of outer space are expected to induce changes in plant genomes, proteomes and metabolic pathways. However, the effect of outer space conditions on the overall physiology of plants at the protein level has yet to be reported. To investigate the effects of outer space conditions on the growth- and development-related physiological processes and metabolic pathways of rice different stages, the seeds of rice variety DN423 were sent into orbit for 12.5 d aboard the SJ-10 Returning Satellite, and then the seedlings of both treated and control rice were compared at the three-leaf stage (TLS) and tillering stage (TS). In addition to comparing plant growth and reactive oxygen species (ROS) levels, seedling proteomes were also compared using isobaric tags for relative and absolute quantitation (iTRAQ). Space flight increased TLS plant height by 20%, reduced and increased ROS levels of the TLS and TS seedlings, respectively, and affected the expression of 36 and 323 proteins in TLS and TS leaves, respectively. Furthermore, the functions of the differentially abundant proteins were mainly associated with metabolism, energy, and protein synthesis and degradation. These results suggested that the exposure of seeds to outer space conditions affects the subsequent abundance of key signaling proteins, gene expression, and the processes of protein synthesis and degradation, thereby affecting metabolic processes and promoting adaptation to the abiotic stress of outer space. As such, the present study sheds light on the effects of space flight on plants and contributes to a more comprehensive understanding of extraterrestrial biology.

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Mitigating N2O and NO Emissions from Direct-Seeded Rice with Nitrification Inhibitor and Urea Deep Placement Kanta Gaihre Yam, Singh Upendra, D. Bible Wendie, Fugice Jr Job, Sanabria Joaquin 2020, 27(5): 434-444.  DOI: 10.1016/j.rsci.2020.03.005 Abstract ( )   HTML ( )   PDF (1067KB) ( )   Soil-emitted nitrous oxide (N2O) and nitric oxide (NO) in crop production are harmful nitrogen (N) emissions that may contribute both directly and indirectly to global warming. Application of nitrification inhibitors, such as dicyandiamide (DCD), and urea deep placement (UDP), are considered effective approaches to reduce these emissions. This study investigated the effects of DCD and UDP, compared to urea and potassium nitrate, on emissions, nitrogen use efficiency and grain yields under direct-seeded rice. High-frequency measurements of N2O and NO emissions were conducted using the automated closed chamber method throughout the crop-growing season and during the ratoon crop. Both UDP and DCD were effective in reducing N2O emissions by 95% and 73%, respectively. The highest emission factor (1.53% of applied N) was observed in urea, while the lowest was in UDP (0.08%). Emission peaks were mainly associated with fertilization events and appeared within one to two weeks of fertilization. Those emission peaks contributed to 65%-98% of the total seasonal emissions. Residual effects of fertilizer treatments on the N2O emissions from the ratoon crop were not significant; however, the urea treatment contributed 2%, whereas UDP contributed to 44% of the total annual emissions. On the other hand, cumulative NO emissions were not significant in either the rice or ratoon crops. UDP and DCD increased grain yields by 16%-19% and N recovery efficiency by 30%-40% over urea. The results suggested that the use of DCD and UDP could mitigate N2O emissions and increase grain yields and nitrogen use efficiency under direct-seeded rice condition.