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[学术文献 ] Fertility restoration of maize CMS‐C altered by a single amino acid substitution within the Rf4 bHLH transcription factor 进入全文
Food and Energy Security
Type C cytoplasmic male sterility (CMS‐C) is the most commonly used form of CMS in maize hybrid seed production. Restorer of fertility 4 (Rf4), the major fertility restorer gene of CMS‐C, is located on chromosome 8S. To positionally clone Rf4, a large F3 population derived from a cross between a non‐restorer and restorer (n = 5104) was screened for recombinants and then phenotyped for tassel fertility, resulting in a final map‐based cloning interval of 12 kb. Within this 12‐kb interval, the only likely candidate for Rf4 was GRMZM2G021276, a basic helix?loop?helix (bHLH) transcription factor with tassel‐specific expression. The Rf4 gene product contains a nuclear localization signal and is likely to not interact directly with the mitochondria. Sequence analysis of Rf4 revealed four encoded amino acid substitutions between restoring and non‐restoring inbreds, however only one substitution, F187Y, was within the highly conserved bHLH domain. The hypothesis that Rf4 restoration is altered by a single amino acid was tested by using clustered regularly interspaced short palindromic repeat (CRISPR)‐CRISPR associated protein 9 (Cas9) homology directed repair (HDR) to create isogenic lines that varied for the F187Y substitution. In a population of these CRISPR‐Cas9 edited plants (n = 780) that was phenotyped for tassel fertility, plants containing F187 were completely fertile, indicating fertility restoration, and plants containing Y187 were sterile, indicating lack of fertility restoration. Structural modeling shows that this amino acid residue 187 is located within the four helix bundle core, a critical region for stabilizing dimer conformation and affecting interaction partner selection.
[学术文献 ] CRISPR/Cas9: An RNA‐guided highly precise synthetic tool for plant genome editing 进入全文
Journal of Cellular Physiology
CRISPR/Cas9 is a newly developed and naturally occurred genome editing tool, which is originally used by bacteria for immune defence. In the past years, it has been quickly employed and modified to precisely edit genome sequences in both plants and animals. Compared with the well‐developed zinc finger nucleases (ZFNs) and transcription activator‐like effector nucleases (TALENs), CRISPR/Cas9 has lots of advantages, including easier to design and implement, higher targeting efficiency, and less expensive. Thus, it is becoming one of the most powerful tools for knockout of an individual gene as well as insertion of one gene and/or control of gene transcription. Studies have shown that CRISPR/Cas9 is a great tool to edit many genes in a variety of plant species, including the model plant species as well as agriculturally important crops, such as cotton, maize, wheat, and rice. CRISPR/Cas9‐based genome editing can be used for plant functional studies and plant improvement to yield, quality, and tolerance to environmental stress.
[前沿资讯 ] 华中农业大学学者揭示乙烯-茉莉酸互作介导水稻根系响应盐胁迫的调控机制 进入全文
互联网
近日，华中农业大学植物科学技术学院尹昌喜课题组揭示了乙烯-茉莉酸互作介导水稻根系响应盐胁迫的调控机制。 盐胁迫是限制全球粮食作物生产的主要非生物胁迫之一。据统计，全世界约有9.3亿hm2的土地遭受盐渍化，约20%的灌溉土地受到盐渍化影响，其中我国的土壤盐渍化面积大约有3600万hm2，严重限制着我国粮食生产。水稻（Oryza sativa L.）是世界上最重要的粮食作物之一，全球约有一半人口以稻米作为主粮。然而，盐胁迫会造成水稻生长发育受阻，最终导致水稻减产。因此，探究水稻耐盐机制，有望为培育耐盐水稻品种、提高盐渍化土地的水稻产量提供理论依据和实践指导，进而保障我国乃至全球的粮食安全。植物激素乙烯（ETH）和茉莉酸（JA）被称为逆境激素，它们参与调控植物响应多种逆境。然而，ETH与JA互作调控水稻种子根响应盐胁迫的分子机制尚不清楚。 该研究发现，盐胁迫通过上调ETH生物合成基因OsSAMS、OsACS和OsACO的转录来促进ETH生物合成；然而，盐胁迫诱导的乙烯不能直接抑制水稻种子根生长，而是通过促进JA的生物合成间接地抑制水稻种子根的生长。此外，盐胁迫还可以通过ETH非依赖途径促进JA的生物合成，进而抑制水稻种子根的生长。进一步研究发现，盐胁迫诱导的JA通过下调OsPLT和细胞分裂相关基因的转录来抑制根分生组织细胞的增殖，盐胁迫诱导的JA还能通过下调OsXTH和OsEXP的转录来抑制根细胞的伸长，从而抑制水稻种子根的生长。 此外，通过比较JA缺失突变体cpm2与其相应野生型水稻的种子根在响应盐胁迫方面的差异，证实了JA能够调控水稻耐盐性。这意味着通过分子标记辅助选择技术、转基因与基因编辑等技术调控JA代谢或信号有望增强水稻耐盐性。该研究成果为培育耐盐水稻品种、提高盐渍化土地的水稻产量提供了理论依据。可见，该研究成果具有广阔的应用前景。
[学术文献 ] Salt tolerance of selected halophytes at the two initial growth stages for future management options 进入全文
scinetific reports
Scarcity of water and the small area of the agricultural land are considered as the crucial environmental issues challenged the Arabian Gulf countries. In this study, experiments were conducted to identify the salt tolerance during the germination and the seedling stages of some native halophytes in the State of Qatar. Seeds of eight native species (Salsola setifera, Halopeplis perfoliata, Caroxylon imbricatum, Suaeda aegyptiaca, Acacia tortilis, Limonium axillare, Tetraena qatarensis and Aeluropus lagopoides) were investigated. Except for Tetraena qatarensis, Acacia tortilis and Suaeda aegyptiaca, all achieved?≥?30% of seed germination at a concentration of 200 mM NaCl. Around 30% of Salsola setifera seeds were able to germinate in a salt concentration of 400 mM. Germination recovery of seeds that have been treated with 800 mM NaCl for 3 weeks was the greatest for Halopeplis perfoliata (94%) and the lowest for Aeluropus lagopoides (22%). Five halophytes were investigated for seedling growth under saline irrigation ranged from 0 to 600 mM NaCl. No significant differences obtained in growth biomass of seedlings of each of Caroxylon imbricatum, Suaeda aegyptiaca and Tetraena qatarensis between saline and non-saline treatments.
[前沿资讯 ] 生物所成功开发出新型转基因检测用生物传感技术 进入全文
互联网
近日，生物所基因安全评价与应用团队利用表面等离子共振技术（SPR），开发了针对核酸靶标的多重、可再生的生物传感技术，为多种转基因元件的检测提供了新的无酶、免扩增的技术支撑，可实现转基因成分的快速高效检测。相关研究成果发表在分析化学经典期刊《塔兰塔（Talanta）》上。 准确、灵敏且快速的分子诊断技术是生物安全检测的基础，生物传感技术为此提供了新的方向与应用策略。研究人员采用表面等离子共振技术，巧妙地设计了多孔道多靶标的分析策略。当含有不同靶标样品注入该芯片后，不同孔道可以输出对应分析物的信号，从而实现多重检测。该策略可实现对转基因元件CaMV35s启动子、nos终止子以及cry1A基因的定性和定量分析，并且检测精度大幅提高。经过条件的优化，该传感技术对于以上三种靶标的检出线可以达到0.1 nM。该方法不仅可以对转基因实现快速筛查，制成的芯片在20天内可以再生使用100次，并且保持较高的检测性能。 该团队近年来围绕农业生物安全风险识别与监测，开发了一系列生物传感器，取得多项进展。其中，基于DNA四面体的微流控生物传感器，通过搭载适配体作为捕获探针，在普通光学显微镜下即可实现10个细胞的快速检测；基于氮掺杂石墨烯纳米片和金纳米(Au/N-G)的电化学生物传感器，可用于检测转基因玉米成分，重复性好，检出限低；基于polyA DNA探针电化学生物传感器，灵敏度高，可区分结构，已成功用于RNAi转基因玉米的检测。这一系列生物传感器的研制成功，为提升转基因生物安全风险识别与预警水平奠定了技术基础，为转基因成分快速高效检测提供了强有力的技术支撑。相关成果发表在《生物传感器与生物电子学（Biosensors and Bioelectronics）》、《微化学学报（Microchimica Acta）》和《分析学家（Analyst）》上。
[学术文献 ] Comparative transcriptome and metabolome profiling reveal molecular mechanisms underlying OsDRAP1-mediated salt tolerance in rice 进入全文
scinetific reports
Integration of transcriptomics and metabolomics data can provide detailed information for better understanding the molecular mechanisms underlying salt tolerance in rice. In the present study, we report a comprehensive analysis of the transcriptome and metabolome of rice overexpressing the OsDRAP1 gene, which encodes an ERF transcription factor and was previously identified to be conferring drought tolerance. Phenotypic analysis showed that OsDRAP1 overexpression (OE) improved salt tolerance by increasing the survival rate under salt stress. OsDRAP1 affected the physiological indices such as superoxide dismutase (SOD), catalase (CAT) and malondialdehyde (MDA) to enhance redox homeostasis and membrane stability in response to salt stress. Higher basal expression of OsDRAP1 resulted in differential expression of genes that potentially function in intrinsic salt tolerance. A core set of genes with distinct functions in transcriptional regulation, organelle gene expression and ion transport were substantially up-regulated in the OE line in response to salt stress, implying their important role in OsDRAP1-mediated salt tolerance. Correspondingly, metabolome profiling detected a number of differentially metabolites in the OE line relative to the wild type under salt stress. These metabolites, including amino acids (proline, valine), organic acids (glyceric acid, phosphoenolpyruvic acid and ascorbic acid) and many secondary metabolites, accumulated to higher levels in the OE line, demonstrating their role in salt tolerance. Integration of transcriptome and metabolome analysis highlights the crucial role of amino acids and carbohydrate metabolism pathways in OsDRAP1-mediated salt tolerance.
