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[前沿资讯] 水稻基因打靶技术研究获进展 进入全文

中国科学院

     中国科学院分子植物科学卓越创新中心研究员朱健康领衔的研究团队,在植物基因组编辑领域再次取得重要进展。研究人员采用修饰后的DNA片段作为供体,在水稻上建立了一种高效的片段靶向敲入和替换技术,高至50%的靶向敲入效率将极大地方便植物的研究和育种。7月6日,相关研究成果在线发表在Nature Biotechnology上。     近年来,CRISPR/Cas介导的植物基因组定点编辑技术在农作物基因功能研究和精准育种中发挥了重要作用,展现了广阔的发展潜力和应用前景。然而,CRISPR/Cas介导的植物基因组定点敲除技术只能在基因组特定位点产生随机插入和删除,精准的片段插入和替换的效率一直很低,限制了其在植物研究和育种上的应用。因此,迫切需要建立更高效的植物基因组片段插入和替换技术体系。     植物基因组编辑是朱健康研究组的重点研究领域,近年来获得了一系列的进展。作为该领域的难题,片段的靶向敲入和替换是科研人员的重要研究目标,并围绕这一目标努力。在建立了病毒介导的同源重组(HDR)和各类单碱基编辑技术等多种方法的同时,科研人员开始尝试在供体DNA片段上寻找突破点,以克服现有方法效率低、应用范围窄等缺陷。核酸修饰在人的RNAi疗法和核酸疫苗等医学领域有广泛的应用。朱健康研究组通过尝试,发现将供体片段同时进行硫代修饰和磷酸化修饰后,能增强CRISPR/Cas9引导的靶向敲入效率(图1)。研究团队先后在14个基因位点上靶向敲入了各类调控元件,包括翻译增强子、转录调控元件,甚至整个启动子,供体片段最长达2049bp。通过对1393株各类T0代基因编辑水稻植株的分析发现,该方法的敲入效率可高达47.3%,平均效率为25%。高效的敲入效率甚至可以同时在四个位点上实现多基因靶向敲入。可以预计,该技术的建立将使靶向敲入成为一项和靶向敲除一样的常规实验,并被各个植物研究和育种单位广泛应用。     在此基础上,朱健康研究团队又设计了一种片段精准替换的策略,称之为重复片段介导的同源重组(TR-HDR)方法。常规的HDR频率极其低下,研究人员在前期的实验中发现,基因组上串联重复片段间的HDR频率非常高。利用这一现象,通过将修饰的片段靶向敲入至目标位点后,人为制造这种串联重复结构,诱导TR-HDR去实现片段替换。采用该技术,在五个基因位点上实现了片段替换和原位的Flag标签蛋白的精准融合,效率最高达到了11.4%(图2)。这一技术突破将有助于植物学研究,并促进农作物定向遗传改良的进程。

[前沿资讯] 格尔木:人工气象服务助力海水稻试验 进入全文

搜狐

据了解,该人工观测气象站在百叶箱、地温观测场中安装了温度计等多种气象仪器,海水稻科研人员可以通过气象仪器开展温度、湿度等关键气象要素的监测,为海水稻种植试验积累可靠的气象资料,也为市气象局下一步开展自动气象站布设,提高气象为农服务水平积累经验。市气象局大气探测技术保障中心副主任马军告诉记者:“今天我们建的这个气象站是人工气象站,主要是观测地温的最高最低值,以及浅层5厘米,10厘米,15厘米,20厘米的地温。近年来,格尔木市气象局加大气象为农服务力度,充分发挥气象对现代农业生产的科技支撑作用,积极探索气象数据监测质量,努力拓展为农服务手段,尤其在枸杞、藜麦等特色农作物种植方面及时提供服务产品,使气象为农服务更具有针对性和指导性,为促进农作物增产农民增收发挥了积极作用。

[前沿资讯] 格尔木盐碱地试种海水稻已成活 进入全文

经济日报

7月2日,在格尔木河西农场7连的70亩海水稻试验田里,绿油油的海水稻田里水汪汪的当天灌溉过水。因为刮风,准备给海水稻施肥的无人机在等待合适的时机。在试验田里,记者见到青岛九天智慧农业集团有限公司育种工程师张国东蹲在地头查看秧苗的生长情况,他拔出长势不好的青苗给记者讲解青苗生根情况。在格尔木试种海水稻是有史以来第一次。张国东说:“此次试种,是青海昆瑶国际贸易有限公司与我们青岛九天智慧农业集团有限公司引进的。”据了解,袁隆平青岛海水稻团队旗下的青岛九天智慧农业集团有限公司利用在育种和种质资源方面的技术优势,通过自主研发的“四维改良法”技术,根据格尔木市土壤情况,从要素物联网系统、土壤定向调节剂、植物生长调节素及抗逆性作物四个方面优化最优配比,通过水稻耐盐碱试验、耐寒试验、耐旱试验等方法,筛选和培育耐寒耐旱水稻品种,培育高原寒地“海水稻”,利用最新科技成果促进地方农业现代化转型,打造“盐碱地改良+海水稻种植+数字化农业”的方式试种海水稻。张国东坦言,按照目前情况看,从育苗大棚栽植到试验田里部分海水稻材料(品种)初步成活,毕竟是第一次试验,无论如何都是结果,这种试验是需要时间的,有多种因素和问题都要考虑到,目前,成活也是一个结果,最终这17个材料表现怎样,得等到9月份才会出结果。此次海水稻试种,格尔木市各级部门比较关注。在海水稻试验田现场,记者遇到农业科学研究所所长曾纪勇,他头戴着遮阳帽在试验田边,联系的旋飞科技公司飞手准备给实验田施肥。

[学术文献] Optimizing rice paddies' lower greenhouse gas emissions and higher yield with SRI management under varying water table levels 进入全文

Paddy and Water Environment

The System of Rice Intensification (SRI) is known as a climate-smart agricultural practice that increases rice production by changing the management of plants, soil, water, and nutrients. SRI water management relies on intermittent irrigation rather than on the continuous flooding of conventionally managed rice production. Different water table levels affect the soil conditions which contribute to different fluxes of greenhouse gas (GHG) emissions. This study estimated the impact on global warming potential (GWP) of GHG emissions from rice paddies when an SRI crop is managed with different water table levels. In this study, CO2 equivalence was assessed using a Simple Greenhouse Gas model, and an artificial neural network model for assessing CH4 and N2O. SRI paddy rice was grown in experimental pots under varying water table treatments, with the water table controlled by using Mariotte tubes set at + 2, 0, - 3, - 5, - 7, and - 12 cm from the soil surface. GHG emissions, which could be monitored more closely in pot trials than in fields, are a composite of the plants' respiration, soil respiration (which is a result primarily of microbial activity), and the respiration that results from root exudates. With SRI practices, rice paddies can serve as a sink rather than a source for CH4 as seen from the negative values for CH4 emissions at all water table treatments. While there were N2O emissions with SRI practice, they were much less in terms of CO2 equivalence than the GWP reduction achieved by reducing CH4. Overall, under the experimental conditions the best water table level for SRI cultivation, with the most rice produced relative to GHG emissions, was - 5 cm from the soil surface. For each kg of grain produced, there were 0.80 kg CO2 eq of GHG emissions. By comparison, a normally flooded paddy field with usual crop management methods emits 1.97 kg CO2 eq per kg of grain produced, almost 150% more. This finding that a water table of - 5 cm is optimal will not necessarily apply for all field conditions, but the research addresses the desirability of seeking to optimize between GHG reductions and increased yield when growing paddy rice, and of developing appropriate methodology for achieving this composite objective.

[学术文献] Integrated approach for seed yield maximization in hybrid rice 进入全文

Annals of Agricultural Research

A field experiment was carried out at ICAR-Indian Institute of Seed Science, Kushmaur, Mau-275 103, Uttar Pradesh during kharif season (rainy) of 2014-15 to know the appropriate hybrid and fertilizer doses for maximization of seed yield in hybrid rice. The study was carried out in split plot design and replicated thrice. The experiment consisted of two hybrid rice, viz. DRRH-2 and DRRH-3 in main plots and five fertilizer application in sub-plot, viz. Control, 100% RDF, 100% RDF+ ZnSO_4 basal @ 25 kg/ha,100% RDF+ZnSO_4 foliar @ 0.5% and 100% RDF+ ZnSO_4 basal @ 25 kg/ha + ZnSO_4 foliar application @ 0.5%. Among two hybrid rice, DRRH-3 was significantly taller than the DRRH-2 at various growth stages i.e., 30, 60, 90 DAT (days after transplanting) and at harvest (52.0, 84.0, 97.7 and 97.7 cm) as compared to DRRH-2. The among four doses of fertilizer, RDF + ZnSO_4 basal + ZnSO_4 foliar was showed higher response, which increases the plant height with increasing plant height at different stages i.e. 30,60,90 DAT and at harvest (55.6,86.3,99.9 cm) as compared to other doses and also over control. The present investigation also revealed that the hybrid DRRH-3 recorded higher panicle length (23.9 cm), seed/panicle (10.1), panicle weight (3.8g), test weight(18.7g), seed & straw yield (8.1 & 39.2q/ha), biological yield (47.3 q/ha) and harvest index (17.3) over DRRH-2. Among fertilizer doses, RDF + ZnSO_4 basal + ZnSO_4 foliar showed positive response, which increased all the yield and yield attributing characters viz., panicle length (24.5 cm), seed/panicle (10.9), panicle weight (5.2 g), test weight (20.0 g), seed yield (8.7 q/ha), straw yield (42.2 q/ha) and biological yield (50.9 q/ha) in both the hybrids compared to other fertilizer doses. DRRH-3 recorded significantly higher values for seed quality parameters viz., germination (93.3%), shoot length (13.7cm), seedling dry weight (0.829 g), vigour index-I & II (2549.6 & 78.2) over DRRH-2. Further fertilizer dose RDF + ZnSO_4 basal + ZnSO_4 foliar showed higher response for seed quality, germination (95.3%), shoot length (13.7 cm), seedling dry weight (0.89 g), vigour index-I & II (2622.9 & 85.7) as compared to other doses.

[前沿资讯] 江苏省耐盐水稻新品种选育及配套栽培技术研究取得良好进展 进入全文

江苏省科学技术厅

近日,江苏省科技厅组织中国工程院陈温福院士、胡培松院士等9位专家对国家科技支撑计划项目“耐盐水稻新品种选育及配套栽培技术研究”系列课题进行了验收,专家组一致认为该项目为沿海滩涂和内陆盐碱地提供了水稻品种和技术支撑,对沿海滩涂资源综合利用,保障国家粮食安全具有重大意义。截至目前,项目累计收集各类水稻种质资源近2万份,筛选耐盐种质1600余份,获得水稻耐盐新基因11个,建成水稻耐盐种质资源数据库1个;利用分子标记辅助选择技术、基因编辑技术与常规育种相结合的方法创制各种耐盐新种质,育成并审定通过适宜不同生态区的耐盐新品种11个;构建了“耕、晒、泡、旋、排”和增施有机肥、绿肥轮作等快速高效脱盐培肥技术体系,形成2‰-3‰的盐碱地上亩产600公斤以上,3‰-6‰盐碱地亩产450公斤以上的栽培模式。项目成果在江苏、山东、吉林含盐量3‰左右改良沿海滩涂和内陆盐碱地大面积应用,亩产量超过400公斤,主要品质达国标3级以上,社会经济效益显著。

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