甘蔗热带种金属硫蛋白家族基因的克隆及响应重金属胁迫的表达分析

金属硫蛋白是一类富含巯基的低分子量蛋白,在植物的重金属解毒及细胞氧化还原调控等方面起重要的作用。本研究以甘蔗热带种Badila组培苗为材料,分别测定了其在CdCl2、ZnSO4和CuCl2水溶液培养条件下地上部和地下部的重金属含量,结果显示其对上述3种重金属有较强的耐受与富集能力。继而克隆了ScMT1(登录号为KJ504373)、ScMT2-1-5(登录号为MH191346)和ScMT3(登录号为KJ5043704)3个金属硫蛋白家族基因,它们分别属于植物MT亚家族中的MT1、MT2和MT3型基因。ScMT1含有1个内含子和2个外显子,开放阅读框(Open Reading Frame,ORF)长228 bp,编码75个氨基酸;ScMT2-1-5含有2个内含子和3个外显子,ORF长246 bp,编码81个氨基酸;ScMT3含有1个内含子和2个外显子,ORF长198 bp,编码65个氨基酸。RT-qPCR显示,Cd2+胁迫下,在甘蔗地上部和地下部,ScMT2-1-5均连续显著上调表达,而ScMT1的上调应答出现延迟。ScMT3在地上部的上调应答出现延迟,在地下部呈“扬-抑”趋势,提示甘蔗响应Cd^2+胁迫过程中ScMT2-1-5起更积极的作用,ScMT1参与胁迫后期的分子响应,而ScMT3不起主导作用。Cu^2+胁迫下,地上部ScMT1连续显著上调表达,ScMT2-1-5和ScMT3呈总体上调的表达趋势;地下部,ScMT1和ScMT2-1-5的上调表答均出现延迟,仅在胁迫后期显著上调表达,而ScMT3仅在胁迫前期显著上调表达。该结果提示了ScMT1、ScMT2-1-5和ScMT3在Cu2+胁迫响应过程中的协作关系,三者共同参与了地上部的胁迫响应,其中ScMT1起更积极的作用;此外三者还先后参与了地下部对Cu^2+胁迫的分子响应。Zn^2+胁迫下,ScMT1和ScMT3分别仅在地上部和地下部显著上调表达;ScMT2-1-5在地上部和地下部均呈“扬-抑”的应答趋势;提示了在甘蔗响应Cd^2+胁迫应答过程中ScMT1和ScMT3分别在地上部和地下部起主要作用,ScMT2-1-5参与了胁迫前期的分子响应。ScMT1、ScMT2-1-5和ScMT3在甘蔗不同组织中及在重金属(Cd^2+、Zn^2+或Cu^2+)不同累积水平下呈现出相似或互补的应答特性,提示上述甘蔗MT家族不同成员在重金属解毒及细胞氧化还原调控等方面产生了功能分化,且三者在应对过量Cd^2+、Zn^2+或Cu^2+对甘蔗组织造成伤害的过程中存在时空上的协同作用。该研究为深入理解多倍体植物甘蔗中MT家族各成员基因在重金属耐受过程中的协同作用机制奠定了基础。     

转基因甘蔗BtG-2的T-DNA侧翼序列分析及其转化事件特异性检测

转基因甘蔗BtG-2是利用农杆菌介导法把Cry1Ac-2A-gna融合抗虫基因导入‘新台糖22号’的转基因甘蔗株系,具有良好的抗虫特性和农艺性状。为了明确转基因甘蔗BtG-2的分子特征及其检测方法,推进其生物安全性评价工作,以BtG-2的T2代为研究材料,利用Southern杂交检测外源基因在转基因甘蔗基因组内的拷贝数;利用染色体步移技术分离外源基因在甘蔗基因组中插入位点的侧翼序列,并建立了该转化体高效灵敏的特异性PCR检测方法。结果表明：Southern杂交检测证明外源T-DNA以单拷贝方式插入BtG-2株系;经过3次的热不对称巢式PCR扩增,获得外源基因T-DNA左边侧翼序列984 bp和右边侧翼序列705 bp;以这2个序列和相应的T-DNA的左右端序列分别设计3对检测引物对,建立了BtG-2株系的转化事件特异性PCR检测方法,扩增效率最高的引物对LS011/LA451和RS160/RA588分别扩增到440 bp和428 bp的特异片段。其中T-DNA左侧设计的LS011/LA451检测引物对扩增的灵敏度高、特异性强,能够在甘蔗BtG-2基因组DNA相对含量为0.1%的模板中检测出转基因目的成分,相当于9个单倍体基因组拷贝数。本研究完成了转基因株系BtG-2的分子特征及其转化事件特异性检测,为该转基因甘蔗及其衍生产品的检测和身份识别提供技术依据。     

Changes in photosynthesis,growth, and sugar content of commercial sugarcane cultivars and Erianthus under flood conditions

Sugarcane (Saccharum spp.) is an economical crop in the tropical and subtropical countries. However, because of global climate change, flooding has become problematic, particularly during the rainy season, in Thailand. We investigated the effects of floods on three commercial sugarcane cultivars, namely NiF8, U-thong 6 (UT6), and U-thong 9 (UT9), as well as Erianthus spp. Growth was assessed using a pot experiment in a glasshouse with two treatments: (1) control and (2) 60 d of flooding followed by 30 d of normal conditions. In comparison with control, during prolonged flooding, Erianthus showed greatly decreased CO₂ assimilation, whereas NiF8, UT6, and UT9 showed slightly declined CO₂ assimilation. Growth in plants subjected to 60 d of flooding was less influenced by floods while sucrose content was not affected except in UT6. During flooding, some roots died, resulting in plants compensating adventitious roots to offset the negative effects of root death and to assist them in maintaining their growth, which appeared from the submerged nodes, with different characteristics for each cultivar. However, 30 d after draining, roots remained damaged, while adventitious roots died, resulting in lesser growth as compared with the control, but it did not significantly affect sucrose content and sugar yield. This study suggests that sugarcane plants need to produce the adventitious roots to compensate their roots’ death during flooding and require time to recover their root system after flooding for obtaining the optimum yield and quality at harvest.     

甘蔗叶不同还田方式对土壤养分的影响

为减轻秸秆焚烧所带来的环境问题和充分利用甘蔗叶资源,在大田环境下动态监测甘蔗叶粉碎、焚烧和深埋3种还田方式对土壤养分的影响。结果表明:甘蔗叶粉碎还田和深埋还田有利于甘蔗叶中有机碳及氮、磷、钾养分的缓慢释放;甘蔗叶焚烧还田提高了土壤碱解氮含量5.6~20.9 mg/kg和速效磷含量0.8~4.0 mg/kg,促进土壤中氮磷向有效态转化,焚烧还田初期显著增加了土壤速效钾的含量12.3~18.3 mg/kg,但焚烧会损失部分甘蔗叶中碳氮元素,也造成环境污染。综合分析认为甘蔗叶粉碎还田是比较省工、方便的处理方式。     

Composition of organic C fractions in soils of different texture affected by sugarcane monoculture

ABSTRACT

Sugarcane is a strategic commodity in Indonesia. It is usually raised in a monoculture system. There is a lack of information about the effects of extended sugarcane monoculture on the soil carbon fraction. The aim of this study was to determine the relative changes in the soil organic C fractions in response to the duration of sugarcane monoculture on Entisols, Inceptisols, and Vertisols. The measured variables were the percentages of sand, silt, and clay, organic matter (OM), total nitrogen (TN), pH (H₂O), cation exchange capacity (CEC), NH₄ ⁺, NO₃ ^-, labile carbon fraction (soil carbon mineralization (C-Min), soil microbial carbon (C-Mic), and carbon particulate organic matter (C-POM)), and stable carbon fraction (humic and fulvic acids). Soil type with sugarcane monoculture period had significant influences on the percentages of clay, sand, silt, CEC, and pH (H₂O). Soil type and sugarcane monoculture period had no apparent significant effect on C-Min or C-POM but did significantly influence C-Mic. The humic and fulvic acid levels in all three soil types were affected by the duration of sugarcane monoculture. To establish the impact of long-term sugarcane monoculture on the physicochemical properties of soils with various textures, it is more appropriate to measure the soil stable carbon fractions such as humic and fulvic acid rather than the soil labile carbon fractions such as C-Min, C-POM, or C-Mic.     

甘蔗品种资源图像信息服务系统简介

采用 Foxpro5 .0 for windows开发出甘蔗品种资源图像信息服务系统 ,本系统由信息数据管理和咨询服务两大模块构成 ,本文主要介绍了甘蔗品种资源图像信息服务系统的运行环境、主要功能及特点     

制糖废水处理方法研究进展

制糖废水是一种高浓度的有机废水 ,如何高效处理是环境工程研究的一个重点。本文就其国外最新的研究成果进行了总结     

Detection, identification and significance of phytoplasmas in grasses in northern Australia

Sugarcane yields have been severely reduced by white leaf and grassy shoot phytoplasma diseases in many parts of Asia. Australian sugarcane crops are not known to be affected by these diseases, but plant pathogenic phytoplasmas found in other introduced and native grasses in northern Australia could pose a serious threat to the Australian sugarcane industry. To further evaluate this threat, leaves from plants of 20 grass species, with and without symptoms, were collected during field surveys in northern Australia and tested to determine whether phytoplasmas were present and whether symptoms were reliable indicators of phytoplasma presence. Molecular tools were used to detect and characterize phytoplasmas. Four different phytoplasmas were found in seven grass species known to grow near healthy sugarcane crops. All the phytoplasmas were closely related to sugarcane white leaf phytoplasma (SCWL), one of the phytoplasmas that causes disease in sugarcane in Asia. Four of the host plant species and two of the phytoplasmas were new records. The relationship between symptoms and phytoplasma presence was poor. Because some plants with symptoms tested negative for phytoplasmas, a series of surveys was carried out in which flowers, leaves, roots and stems of two known host plant species, Whiteochloa cymbiformis and Sorghum stipoideum, were tested separately on nine occasions during two wet seasons. This was done to investigate the distribution of phytoplasmas within plants over time. Results showed that spatial and temporal variation of phytoplasmas occurred in these two host plant species. Hence, evaluation of disease distribution within a region requires repeated testing of all plant parts from plants without symptoms, as well as those with symptoms. To date, there is no report of a vector capable of transmitting to Australian sugarcane the phytoplasmas found in grasses in this study. If one is present, or occurs in the future, then native and introduced grasses could constitute a large reservoir of phytoplasma for vectors to draw on. This work provides an early warning for the sugarcane industry that the potential for infection exists.     

全国甘蔗野生种质资源的采集和考察

１９８５～１９９３年在全国进行了甘蔗野生种质资源的采集和考察。采集到甘蔗亚族（Ｓａｃｃｈａｒｉｎａｅ）内９个属１８个种的无性系共８２４份，种植在云南农业大学校园内（昆明黑龙潭），建立了甘蔗资源圃。考察了甘蔗属（Ｓａｃｃｈａｒｕｍ）、蔗茅属（Ｅｒｉａｎｔｈｕｓ）、河八王属（Ｎａｒｅｎｇａ）和芒属（Ｍｉｓｃａｎｔｈｕｓ）中主要野生种的地理分布、开花期、形态特征、繁殖方式、生态适应性、锤度和种质流失的情况。探明了割手密（Ｓ．ｓｐｏｎｔａｎｅｕｍＬ．）和斑茅（Ｓ．ａｒｕｎｄｉｎａｃｅｕｍＲｅｔｚ）的开花期与原产地纬度和海拔的相关，探索了割手密与蔗茅（Ｅ．ｆｕｌｖｕｓＮｅｅｓ）茎秆锤度与地理分布的联系。     

A streak disease of pearl millet caused by a leafhopper-transmitted geminivirus

The cause of a streak disease of pearl millet (Pennisetum glaucum), originating from Nigeria, has been attributed to a geminivirus belonging to the African streak virus cluster. A full-length, infectious clone of the virus was obtained which was transmissible by the vectorCicadulina mbila (Naudé). Analysis of the complete nucleotide sequence of the coat protein gene of this virus shows it to be most closely related to sugarcane streak virus. The possible evolutionary implications of this finding are discussed.