转自中关村旭月非损伤微测技术产业联盟

期刊：Chemosphere
主题：浮萍超富集Cd的分子机制研究
标题：Comparative transcriptome analysis of duckweed (Landoltia punctata) in response to cadmium provides insights into molecular mechanisms underlying hyperaccumulation
影响因子：4.427
检测指标：Cd²⁺流速
检测样品：浮萍根（根尖、距离根尖400μm，1000μm）
Cd²⁺流速实验处理方法：0 μM CdCl2处理30min
Cd²⁺流实验测试液成份：0.1 mM KCl，0.1 mM MgCl2、0.05 mM CaCl2、0.3 mM MES、50μM CdCl2，pH5.5
作者：中科院青岛生物能源与过程研究所周功克、徐华

英文摘要

Cadmium (Cd) is a detrimental environmental pollutant. Duckweeds have been considered promising candidates for Cd phytoremediation. Although many physiological studies have been conducted, the molecular mechanisms underlying Cd hyperaccumulation in duckweeds are largely unknown.

In this study, clone 6001 of Landoltia punctata, which showed high Cd tolerance, was obtained by large-scale screening of over 200 duckweed clones. Subsequently, its growth, Cd flux, Cd accumulation, and Cd distribution characteristics were investigated. To further explore the global molecular mechanism, a comprehensive transcriptome analysis was performed. For RNA-Seq, samples were treated with 20 μM CdCl2 for 0, 1, 3, and 6 days.

In total, 9,461, 9,847, and 9615 differentially expressed unigenes (DEGs) were discovered between Cd-treated and control (0 day) samples. DEG clustering and enrichment analysis identified several biological processes for coping with Cd stress. Genes involved in DNA repair acted as an early response to Cd, while RNA and protein metabolism would be likely to respond as well.

Furthermore, the carbohydrate metabolic flux tended to be modulated in response to Cd stress, and upregulated genes involved in sulfur and ROS metabolism might cause high Cd tolerance. Vacuolar sequestration most likely played an important role in Cd detoxification in L. punctata 6001. These novel findings provided important clues for molecular assisted screening and breeding of Cd hyperaccumulating cultivars for phytoremediation.

中文摘要（谷歌机翻译）

镉（Cd）是有害的环境污染物。浮萍被认为是镉植物修复的有前途的候选人。尽管已进行了许多生理研究，但浮萍中Cd过度富集的分子机制尚不清楚。

在这项研究中，通过大规模筛选200多个浮萍克隆，获得了对镉具有高耐受性的Landoltia punctata克隆6001。随后，研究了其生长，Cd通量，Cd积累和Cd分布特征。为了进一步探索全局分子机制，进行了全面的转录组分析。对于RNA-Seq，样品用20μMCdCl2处理0、1、3和6天。

在经镉处理的样品和对照（0天）样品之间总共发现了9,461、9,847和9615个差异表达的单基因（DEG）。 DEG聚类和富集分析确定了应对Cd胁迫的几种生物学过程。参与DNA修复的基因是对Cd的早期反应，而RNA和蛋白质代谢也可能也有响应。

此外，碳水化合物的代谢通量倾向于响应Cd胁迫而被调节，而参与硫和ROS代谢的基因上调可能导致对Cd的高耐受性。液泡螯合最有可能在点球藻6001的Cd解毒中发挥重要作用。这些新发现为分子辅助筛选和育种Cd超富集植物进行植物修复提供了重要线索。

文章链接：https://www.sciencedirect.com/science/article/pii/S0045653517315680?via%3Dihub

Tree Physiol ：中科院南土所丨红柳和棉花在干旱胁迫下对硝吸收的差异​（附NMT实验体系）

期刊：Tree Physiology
主题：红柳和棉花在干旱胁迫下对硝吸收的差异标题：Characterization and comparison of nitrate fluxes in Tamarix ramosissima and cotton roots under simulated drought conditions
影响因子：3.389
检测指标：NO₃^-流速
检测样品：红柳、棉花根部（距离根尖5mm，20mm）
NO₃^-流速流实验处理方法：
15% PEG瞬时处理
NO₃^-流速流实验测试液成份：
0.1 mM KNO3, 0.1 mM MgCl2, 0.1 mM NaCl, 0.1 mM CaCl2 and 0.3 mM 2-(N-morpholino) ethanesulfonic acid hydrate (MES), pH 6.2
作者：中科院南京土壤所施卫明、李光杰、张琳

英文摘要

Tamarix ramosissima Ledeb., a major host plant for the parasitic angiosperm Cistanche tubulosa, and known for its unique drought tolerance, has significant ecological and economic benefits. However, the mechanisms of nitrogen acquisition by the T. ramosissima root system under drought have remained uncharacterized.

Here, uptake of nitrate (NO3−) in various regions of the root system was measured in T. ramosissima using Non-invasive Micro-test Technology at the cellular level, and using a 15NO3–-enrichment technique at the whole-root level. These results were compared with responses in the model system cotton (Gossypium hirsutum L.). Tamarix ramosissima had lower net NO3– influx and a significantly lower Km (the apparent Michalis–Menten constant; 8.5 μM) for NO3– uptake than cotton under normal conditions.

Upon simulated drought conditions, using polyethylene glycol (PEG), NO3– flux in cotton switched from net influx to net efflux, with a substantive peak in the white zone (WZ) of the root. There were no significant NO3– influx signals observed in the WZ of T. ramosissima under control conditions, whereas PEG treatment significantly enhanced NO3– influx in the WZ of T. ramosissima. The effect of PEG application on NO3– fluxes was highly localized, and the increase in net NO3– influx in response to PEG stimulation was also found in C. tubulosa-inoculated T. ramosissima. Consistently, root nitrogen (N) content and root biomass were higher in T. ramosissima than in cotton under PEG treatment.

Our study provides insights into NO3– uptake and the influence of C. tubulosa inoculation in T. ramosissima roots during acclimation to PEG-induced drought stress and provides guidelines for silvicultural practice and for breeding of T. ramosissima under coupled conditions of soil drought and N deficiency.

中文摘要（谷歌机翻译）

Tamarix ramosissima Ledeb。是寄生被子植物肉stan蓉的主要寄主植物，以其独特的耐旱性而闻名，具有显着的生态和经济效益。然而，在干旱条件下，T。ramosissima根系对氮素的吸收机制尚未阐明。

在这里，使用非侵入性微测试技术在细胞水平上使用毛细线虫，并在全根水平上使用15NO3-富集技术测量了毛滴虫在根系各个区域中硝酸盐（NO3-）的吸收。将这些结果与模型系统棉（Gossypium hirsutum L.）中的响应进行比较。在正常条件下，柳的净NO3-流入量较低，而NO3-吸收量的Km（表观Michalis-Menten常数； 8.5μM）则显着低于棉花。

在模拟干旱条件下，使用聚乙二醇（PEG），棉花中的NO3-通量从净流入量转换为净流出量，在根部的白色区域（WZ）出现一个实质性的峰值。在控制条件下，没有观察到明显的NO3-流入信号，而PEG处理显着增强了T. ramosissima的W3区NO3-流入。 PEG施用对NO3-通量的影响高度局限，并且在接种C.tubulosa的T. ramosissima中还发现了响应PEG刺激的NO3-净流入量的增加。一致地，在PEG处理下，T.ramosissima的根氮（N）含量和根生物量均高于棉花。

我们的研究为适应PEG诱导的干旱胁迫提供了NO3的吸收以及在T. ramosissima根中接种C.tubulosa的影响，并为土壤干旱和N耦合条件下的营林实践和T. ramosissima育种提供了指导。不足。

结果表明：使用PEG进行瞬时处理后，棉花根系的NO₃^-由吸收转为外排，最高值可达400 pmol·m^-2·s^-1，由此降低根系的N含量；而红柳根系经PEG瞬时处理后吸收明显增加，最高可达300 pmol·m^-2·s^-1，提高了根系的N含量。

文章链接：https://academic.oup.com/treephys/article-abstract/39/4/628/5253231?redirectedFrom=fulltext

转自中关村旭月非损伤微测技术产业联盟

期刊：New Phytologist
主题：根系铁毒敏感机制同一氧化氮调控的根尖区钾离子稳态平衡密切相关
标题：Excess iron stress reduces root tip zone growth through nitric oxide-mediated repression of potassium homeostasis in Arabidopsis
影响因子：7.433
检测指标：K⁺流速
检测样品：拟南芥
K⁺流实验处理方法：4°C下冷处理48小时
K⁺流实验测试液成份：2 mM KH₂PO₄、5mM NaNO₃、2 mM MgSO₄、1 mM CaCl₂、50lM Fe-EDTA，50 lMH₃BO₃、12lM MnSO₄、1lM ZnCl₂ ，1lM CuSO₄、0.2lMNa₂MoO₄、1％蔗糖，0.5 g / l MES和0.8％琼脂 pH 5.7
作者：中国科学院土壤研究所土壤与可持续农业国家重点实验室施卫明、李光杰、张琳

文章简介

铁毒是热带和淹水土壤常见的障碍因子。植物发生铁毒害时，根系生长受阻，严重时根系腐坏死亡。然而，人们对铁毒抑制植物根系发育的生物学机制的认识还很初步，也不利于对土壤铁毒逆境下保根壮苗等农艺技术的研发。

中科院南京土壤所施卫明研究员课题组长期关注根系铁毒害分子响应机制，分别在铁毒抑制植物的根系伸长、侧根形成的分子生理机制等方面取得一系列进展。相关结果陆续发表在Plant Physiology, Journal of Experimental Botany（Li Guangjie et al., 2015a,b）上。相关成果得到了国内外同行的广泛关注，受Frontiers in Plant Science和Plant Signal and Behavior期刊邀请撰写发表了相关综述和评论（Li Guangjie et al., 2016a,b）。文章中用到的新型分根研究方法，也受到国际知名的方法学期刊Bio-Protocol的邀请撰写了详细的介绍文章（Li Guangjie et al., 2017）。

上述系列研究证实根尖区是根系生长响应铁毒胁迫的关键位点，而且比根系其它区段对铁毒胁迫更加敏感。但是为何根尖区会对铁毒胁迫更加敏感，仍未探究清楚。围绕该科学问题，该团队进行了更深入研究。利用非损伤微测技术（Non-invasive Micro-test Technology, NMT）测定不同根系区段的钾离子流，并配合离子通道抑制剂和相关突变体进行了研究。

研究发现铁毒胁迫引发根尖区细胞一氧化氮（NO）上升后诱导了SNO1 (sensitive to nitric oxide 1)//SOS4活性增强。进而加剧非选择性离子通道（NSCC）介导的钾离子外流，造成根尖细胞钾离子稳态失衡，从而导致了根尖区对铁毒胁迫非常敏感。有意思的是，补充供钾可以一定程度上缓解铁毒胁迫，但是因为没有清除铁毒胁迫诱导的NO信号和SNO1/SOS4活性，因此，并不能彻底解除铁毒对根系的伤害。研究结果也说明了，抑制NO信号和SNO1/SOS4活性以及补施钾肥都对提升植物抵御土壤铁毒逆境有重要作用，但在源头上抑制铁毒诱导的NO信号和SNO1/SOS4活性更为重要和有效。相关结果已在New Phytologist（Zhang Lin and Li Guangjie et al., 2018）发表。张琳博士为第一作者，施卫明研究员和李光杰副研究员为文章通讯作者。

实时加入Fe试剂后，拟南芥根尖K+吸收速率变化情况

英文摘要

The root tip zone is regarded as the principal action site for iron (Fe) toxicity and is more sensitive than other root zones, but the mechanism underpinning this remains largely unknown.

We explored the mechanism underpinning the higher sensitivity at the Arabidopsis root tip and elucidated the role of nitric oxide (NO) using NO‐related mutants and pharmacological methods.

Higher Fe sensitivity of the root tip is associated with reduced potassium (K+) retention. NO in root tips is increased significantly above levels elsewhere in the root and is involved in the arrest of primary root tip zone growth under excess Fe, at least in part related to NO‐induced K+ loss via SNO1 (sensitive to nitric oxide 1)/SOS4 (salt overly sensitive 4) and reduced root tip zone cell viability. Moreover, ethylene can antagonize excess Fe‐inhibited root growth and K+ efflux, in part by the control of root tip NO levels.

We conclude that excess Fe attenuates root growth by effecting an increase in root tip zone NO, and that this attenuation is related to NO‐mediated alterations in K+ homeostasis, partly via SNO1/SOS4.

中文摘要（谷歌机翻译）

根尖区被认为是铁（Fe）毒性的主要作用部位，比其他根区更敏感，但其根源机理尚不清楚。

我们探索了支持拟南芥根尖较高敏感性的机制，并使用NO相关突变体和药理方法阐明了一氧化氮（NO）的作用。

根尖的高Fe敏感性与钾（K +）保留减少有关。根尖中的NO显着高于根中其他位置的水平，并且参与了过量Fe下主要根尖区的生长的抑制，至少部分与NO诱导的通过SNO1（对一氧化氮1敏感）导致的K +损失有关/ SOS4（盐过于敏感4）并降低了根尖区细胞的活力。此外，乙烯可以拮抗过量铁抑制的根生长和钾离子外排，部分原因是通过控制根尖NO含量。

我们得出结论，过量的铁会通过增加根尖区NO的含量而减缓根的生长，并且这种衰减与NO介导的K +动态平衡的改变有关，部分是通过SNO1 / SOS4引起的。

文章链接：https://nph.onlinelibrary.wiley.com/doi/full/10.1111/nph.15157

转自中关村旭月非损伤微测技术产业联盟

NMT是基因功能的活体检测技术，已被31位诺贝尔奖得主所在单位，及北大、清华、中科院使用。

• 期刊：Chemosphere
• 主题：盐度调控的海洋硅藻细胞表面镉离子流
• 标题：Salinity-dependent nanostructures and composition of cell surface and its relation to Cd toxicity in an estuarine diatom
• 影响因子：4.427
• 检测指标：Cd²⁺流速
• 检测部位：硅藻藻细胞
• Cd²⁺流速流实验处理方法：不同盐度的硅藻细胞
• Cd²⁺流速流实验测试液成份：0.1mM KCl,0.1mM MgCl2, 0.5mM NaCl, 0.3mM 2-(N-morpholino) ethanesulfonic acid (MES), 0.2mM Na2SO4 and 0.1% sucrose, pH 8.0，8.9μM CdCl2
• 作者：深圳大学潘科、马捷

文章简介

盐度是河口环境中变化较大的因子之一，会影响海洋主要初级生产力——硅藻与金属之间的相互作用，之前研究发现这一影响主要由环境水化学变化引起。但却忽略了盐度也可能通过改变硅藻本身的生理生化状态来影响其响应重金属的过程。

此项研究模拟河口的盐度梯度，在18，25，和32 psu三个盐度下培养了新月菱形藻，在18 psu低盐度时，施加8.9 μM的Cd²⁺对细胞生长的抑制最强。但值得注意的是，Cd离子浓度的升高约一倍，引起的细胞生长抑制却是约四倍，说明Cd重金属毒性的增加可能存在着其它机制。从分布上看，大部分（>75%）Cd都吸附于细胞表面，表明新月菱形藻的细胞壁在最初的Cd累积过程中有着重要的作用。

基于上述现象，研究利用非损伤微测技术测定不同盐度培养的硅藻单细胞表面的Cd²⁺离子流。结果发现，硅藻细胞在低盐度时细胞表面的Cd²⁺离子流速更快，而Cd²⁺吸收速率是影响其毒性最主要因素。进一步结合其它物理化学手段最终揭示了硅藻在不同盐度下通过改变细胞壁的功能基团种类和数量来影响其吸附Cd的细胞表面化学机制。

此项研究为近海盐度强烈变化条件下防控重金属的污染和食物链传递提供了重要的理论依据。

不同盐度培养的新月菱形藻，细胞表面Cd²⁺离子流的差异性。负值表示吸收。

英文摘要

The interactions between metal and phytoplankton are affected by salinity in estuarine environments. While water chemistry is an important factor regulating the metal bioavailability in phytoplankton, the physiological adaptation of the algae cells may also change their intrinsic response to metals.

In this work, we tried to interpret the salinity-dependent Cd toxicity in a pennate diatom Nitzchia closterium from a biological side. As with many studies, we observed Cd toxicity to the diatom increased with decreasing salinity. However, changing free Cd ion concentrations may be partly responsible for the enhanced Cd toxicity.

Multiple evidences showed that diatom cells acclimated at low salinity had stronger intrinsic Cd adsorption capacity. Salinity significantly affected not only the nanostructures but also the biochemical composition in the cell surface of the diatom. Diatom cells grown at lower salinity had a lower surface potential, higher specific surface area, and more sulfur-containing groups in the cell wall, leading to stronger Cd binding capacity in the cells. Meanwhile, more Si was present as poly-silicic acid when the salinity decreased. The change of Si content and speciation in the cell wall are also considered a major reason for the variations of Cd surface binding.

Our study provided new clues for the salinity-dependent metal toxicity in marine diatoms.

中文摘要（谷歌机翻）

在河口环境中，盐度影响金属和浮游植物之间的相互作用。尽管水化学是调节浮游植物中金属生物利用度的重要因素，但藻类细胞的生理适应性也可能改变其对金属的内在响应。

在这项工作中，我们试图从生物学的角度来解释盐度依赖的Cd毒性在戊二烯硅藻Nitzchia closterium中。与许多研究一样，我们观察到Cd对硅藻的毒性随着盐度的降低而增加。但是，改变游离Cd离子浓度可能是造成Cd毒性增强的部分原因。

多种证据表明，低盐度适应的硅藻细胞具有更强的固有Cd吸附能力。盐度不仅显着影响硅藻的纳米结构，而且显着影响硅藻细胞表面的生化组成。在较低盐度下生长的硅藻细胞具有较低的表面电势，较高的比表面积和细胞壁中更多的含硫基团，从而导致细胞中更强的Cd结合能力。同时，当盐度降低时，更多的Si作为聚硅酸存在。 Si含量的变化和细胞壁中的形态也被认为是Cd表面结合变化的主要原因。

我们的研究为海洋硅藻的盐度依赖性金属毒性提供了新的线索。

文章链接：https://www.sciencedirect.com/science/article/pii/S0045653518319891?via%3Dihub