Analysis of genetic diversity and phylogeny in Saccharum and related genera using RAPD markers

Molecular diversity in Saccharum complex was studied using 195 RAPD markers generated by 12 random primers. Among the Saccharum species, S. officinarum showed a low level of genetic diversity while S. sinense was found to be more diverse. Six taxonomical groups were clearly resolved in the cluster analysis. S. officinarum, S. robustum, S. spontaneum and Erianthus spp. formed discrete groups. S. barberi and S. sinense formed a single cluster, so also Narenga and Sclerostachya. S. officinarum was found to be closer to S. robustum and distant from S. spontaneum. Among the related genera, Sclerostachya was closer to Saccharum while Erianthus was found to be highly divergent from all the Saccharum species. Six of the primers used generated RAPD fragments unique to Erianthus. It is suggested that the Erianthus spp. can contribute substantially towards sugarcane varietal improvement in view of its greater divergence with Saccharum.     

Genetic diversity of North American and Old World Saccharum assessed by RAPD analysis

Saccharum (= Erianthus) native to North America is an untapped germplasm for genetic improvement of sugarcane (Saccharum spp. hybrids). There are five species and two varieties native to North America: S. alopecuroideum, S. baldwinii, S. brevibarbe vars. brevibarbe and contortum, S. coarctatum, and S. giganteum. There are three cytotypes of S. giganteum (2n = 30, 60, 90), and they overlap in gross morphology. Our objectives were to compare genetic diversity of North American and Old World members of Saccharum. Bulked DNA for five North American species, three Old World Erianthus spp. sect. Ripidium clones, and five sugarcane cultivars was tested by PCR with 13 RAPD primers. A total of 283 repeatable RAPD bands was scored for the nine taxa. Genetic distance coefficients ranged from 0.365 to 0.767 indicating substantial diversity among taxa. Taxa were assigned to one of three cluster groups: 1) S. baldwinii, S. brevibarbe var. contortum, S. coarctatum, and S. giganteum 2n = 90; 2) S. gig anteum 2n = 30 and 2n = 60, S. alopecuroideum, and sugarcane cultivars; and 3) Old World Erianthus spp. The RAPD analysis indicated that sugarcane was genetically more similar to North American Saccharum than it was to Old World Erianthus. This was unexpected given that North American Saccharum is geographically, cytologically, morphologically, and possibly reproductively isolated from Old World Erianthus and sugarcane. The data support the taxonomic separation of cytotypes of S. giganteum.     

Characterization of Intergeneric Hybrids of Saccharum using Molecular Markers

The potential use of RAPD markers in identifying genuine intergeneric hybrids of Saccharum was examined in 12 hybrids of Saccharum with Erianthus spp., Sorghum bicolor and Zea mays. In the three groups of hybrids examined, RAPD markers could precisely identify the true hybrids of Saccharum officinarum × Sorghum bicolor and Saccharum officinarum × Zea mays. Though Erianthus had a very distinct RAPD profile and as many as 107 Erianthus-specific bands were identified, a decisive profile that can identify all the hybrids could not be obtained. The strong molecular differentiation between S.officinarum and Erianthus was not adequately resolved in the RAPD profiles of their hybrid progenies which suggest that more refined molecular techniques will be required for the characterization of Saccharum–Erianthus hybrids.     

A short review on sugarcane: its domestication,molecular manipulations and future perspectives

Sugarcane (Saccharum spp.) is a special crop plant that underwent anthropogenic evolution from a wild grass species to an important food, fodder, and energy crop. Unlike any other grass species which were selected for their kernels, sugarcane was selected for its high stem sucrose accumulation. Flowering in sugarcane is not favored since flowering diverts the stored sugar resources for the reproductive and developmental energy needs. Cultivars are vegetatively propagated and sugarcane breeding is still essentially focused on conventional methods, since the knowledge of sugarcane genetics has lagged that of other major crops. Cultivar improvement has been extremely challenging due to its polyploidy and aneuploidy nature derived from a few interspecific hybridizations between Saccharum officinarum and Saccharum spontaneum, revealing the coexistence of two distinct genome organization modes in the modern variety. Alongside implementation of modern agricultural techniques, generation of hybrid clones, transgenics and genome edited events will help to meet the ever-growing bioenergy needs. Additionally, there are two common biotechnological approaches to improve plant stress tolerance, which includes marker-assisted selection (MAS) and genetic transformation. During the past two decades, the use of molecular approaches has contributed greatly to a better understanding of the genetic and biochemical basis of plant stress-tolerance and in some cases, it led to the development of plants with enhanced tolerance to abiotic stress. Hence, this review mainly intends on the events that shaped the sugarcane as what it is now and what challenges ahead and measures taken to further improve its yield, production and maximize utilization to beat the growing demands.

     

甘蔗组织中苹果酸酶活性的研究

甘蔗幼苗的苹果酸酶活性主要分布在叶片中,在叶鞘、幼茎和苗根中很少。甘蔗+1叶的苹果酸酶活性在分蘖末期出现高峰,以后一般随生长进程而呈下降趋势。在工艺成熟期甘蔗受到重霜危害时,+1叶中的苹果酸酶活性几乎消失。不同基因型之间的苹果酸酶活性也表现出明显的差异,但在不同的生长期表现不同,与当时所处的生长状况有关,生势较旺盛的一般活性较高。     

甘蔗尿苷二磷酸葡萄糖焦磷酸化酶基因(UGPase)转化拟南芥及转基因植株的生理特性分析

尿苷二磷酸葡萄糖焦磷酸化酶(UDP-glucose pyrophosphorylase,UGPase)是植物糖代谢的主要参与酶之一,在植物的生长发育过程中起着重要作用。本研究将甘蔗(Saccharum officinarum)UGPase基因cDNA片段连接至载体pBI121,通过BamHⅠ和SacⅠ酶切鉴定及测序验证,结果表明,植物表达载体成功构建;通过农杆菌(Agrobacterium tumefaciens)的介导,采用浸花法转化拟南芥(Arabidopsis thaliana)。结合卡那霉素抗性筛选和PCR检测,获得了5株T0代转基因植株。对T1代转基因植株进行PCR及Southern blot分析,结果表明,目的基因已成功转入拟南芥中,并且不同的转化植株含有目的基因的拷贝数不同。对T2代转基因植株进行PCR和RT-PCR检测,结果表明,目的基因不仅能在自交系后代中稳定遗传,而且在RNA水平也有表达。同时,对T2代转基因植株的可溶性总糖、蔗糖及淀粉含量进行测定,结果表明,与野生型相比,转基因植株中可溶性总糖含量没有明显的变化,但蔗糖含量有所提高,并且差异明显,比野生型植株提高了50.85%~96.99%,而淀粉含量都较野生型植株的低,降低了9.69%~36.76%。说明UGPase在蔗糖与淀粉的转换过程中起着较为重要的作用,其催化的反应方向影响着组织中这两种产物(蔗糖和淀粉)的分配。     

氯化胆碱对甘蔗光合性能及糖含量的影响

以不同浓度的氯化胆碱（ＣＣ）处理田间栽培甘蔗。经合适浓度的ＣＣ处理的甘蔗叶绿素含量、叶内Ｍｇ２＋-ＡＴＰａｓｅ和Ｃａ２＋-ＡＴＰａｓｅ，ＮＡＤＰ一苹果酸酶和磷酸烯醇式丙酮酸（ＰＥＰ）羧化酶等活性，叶绿体的希尔（Ｈｉｌｌ）反应活力和光合速率都有不同程度的提高，甘蔗的株高、茎粗、蔗茎含糖量也有所提高。     

Characterization of intergeneric hybrids of <Emphasis Type="Italic">Erianthus rockii</Emphasis> and <Emphasis Type="Italic">Saccharum</Emphasis> using molecular markers

Erianthus rockii, a wild relative of sugarcane, is drought and cold tolerant, and both are potentially important agronomic traits to the sugarcane industry worldwide. As such it is of interest as a source of parental germplasm to sugarcane breeders and is currently being used in sugarcane introgression programs in both China and Australia. To date morphological characters have been used to verify the putative hybrids produced. Two crosses were generated between two different Saccharum species and two E. rockii accessions. Over 400 AFLP markers were used to identify the intergeneric hybrid progeny as well as determine hybrid diversity. Both crosses generated hybrids but efficiency levels were very different and are probably related to the different Saccharum parent used in each cross. Cross 1 was between a Saccharum officinarum and E. rockii and generated 100% hybrid progeny. Cross 2, however, was between a sugarcane hybrid (S. officinarum × Saccharum spontaneum) and E. rockii and only 10% of the progeny were intergeneric hybrids. Inheritance of markers in the progeny was analysed and for both crosses there were equal numbers of markers from both parents indicating n + n transmission of chromosomes. This is the first verification of E. rockii hybrids with molecular markers. It may now be possible to exploit genes of value from E. rockii in sugarcane breeding programs.     

MODIS与ETM数据在甘蔗长势遥感监测中的应用

广西是主要糖业生产基地之一,甘蔗的长势和产量作为一种基础信息,对于政府决策、糖业企业经营规模和甘蔗种植户田间管理等方面都具有非常重要的参考价值。本文从遥感监测入手,利用MODIS资料,采用归一化植被指数的方法监测甘蔗长势。同时利用ETM资料的高空间分辨率的优势,采用监督分类方法提取相关的地表特征,排除监测区内非甘蔗用地信息的干扰。ETM和MODIS资料的结合提高了甘蔗长势监测的精度,可为甘蔗估产奠定基础。     

利用叶片生化性状预测不同基因型甘蔗产量和品质的研究

分别在伸长后期和工艺成熟前期取样分析了9个甘蔗基因型叶片中的10个生化性状,发现多种酶活性,蛋白质和光合色素含量等与甘蔗的经济性状有一定的联系,但只用某个生化性状预测经济性状具有较大的局限性.以10个叶片生化性状作为自变量,分别以甘蔗产量和品质性状作为依变量进行多元回归分析,能建立多个达到显著水平的多元回归模型,表明利用多个叶外生化性状对不同基因型甘蔗产量和品质进行预测是可能的.     

影响湛江甘蔗产量与糖分的气候因子变化特征

对影响湛江甘蔗产量和糖分的气候因子近55 a来的趋势性、阶段性和周期性进行分析。结果表明：影响甘蔗产量的气候因子中,3-10月的积温增加趋势显著;3-10月的积温和降水量有显著的阶段性;3-10月的积温、降水量、日照时数和大风次数都有显著的振荡周期,总日照时数有11 a、3-4 a的振荡周期,大风有5-6 a、7-8 a的振荡周期。影响甘蔗糖分的气候因子中,10-11月的平均最低气温增加趋势比较显著,有显著的周期性和阶段性;11月-次年2月的降水量有显著的阶段性和2-3 a的振荡周期。     

乙烯利对甘蔗茎内IAA氧化酶活性动态变化的影响

测定了甘品种桂粮１１号、桂糖１５号和新台糖１６号节间２的ＩＡＡ氧化酶活性的动态变化以及乙烯利处理后的酶活性变化。结果表明：在甘蔗工艺成熟过程中,茎内ＩＡＡ氧化酶酶活性的变化主要表现为先升后降的变化过程,品种间有差异。乙烯利处理对ＩＡＡ氧化酶活性有影响,其影响效应及影响时间因品种而有差异,主要表现为抑制ＩＡＡ氧化酶活性的早期上升过程,同时钝化ＩＡＡ氧化酶对外界环境的反应,酶活性变化对照波动性要小,影     

Detection of nifH Sequences in Sugarcane (Saccharum officinarum L.) and Pineapple (Ananas comosus [L.] Merr.)

To detect N₂-fixing bacteria in a plant without using culture methods, nifH gene segments were amplified with degenerate primers from DNA extracted from stems of sugarcane ( Saccharum officinarum L.) and leaves of pineapple ( Ananas comosus [L.] Merr.). Sequences of the nifH clones were homologous to those of bacteria in the genera Bradyrhizobium, Serratia , and Klebsiella. The bacteria with nifH sequences homologous to those of the three genera may be promising candidates for predominant endophytic diazotrophs in sugarcane and pineapple, because these sequences were commonly detected in samples from different host plants, which were collected at different locations. On the other hand, no nifH sequence related to Gluconacetobacter diazotrophicus , which is an endophytic N₂-fixing bacterium and had been previously isolated from sugarcane, was detected in sugarcane. This indicates the absence or the presence of few G. diazotrophicus in the stems of the sugarcane plants used in the current study.     

Disturbances in Growth,Yield, Sucrose Concentration and Antioxidative Defense System by Excess Cobalt in Sugarcane

The aim of the study was to implicate induction of oxidative stress and antioxidative responses with the effects of cobalt excess on sugarcane plants. Sugarcane (Saccharum officinarium L.) cv. ‘CoS 99225’ grown in refined sand at excess cobalt i.e. 100, 200, 300, 400, and 500 μM. The effect of excess cobalt (>300 μM) was observed on sugarcane as interveinal chlorosis and necrotic spots in middle leaves. Later, affected leaves turned necrotic, dry, and withered. The toxicity of cobalt was also discernible on root weight, cane yield, reduced concentration of sucrose in cane juice, carotenoides, Hill reaction activity, chlorophylls, iron (Fe), relative water content, decreased activity of catalase in leaves, and increase in concentration of lipid peroxidation, phenols, sugars, starch, proline and higher activity of peroxidase, ascorbate peroxidase and superoxide didmutase and accumulation of cobalt in sugarcane leaves.     

三种生长调节剂对甘蔗生长和蔗糖分积累的影响

对处于伸长生长后期的两个甘蔗品种,用三种生长调节剂进行叶面喷施试验。结果表明,粤糖71/210经草甘膦处理及桂糖11经乙烯利处理后,有降低叶片含水量,减少绿叶面积的作用,表现有良好的催熟增糖效果.增糖最佳时期为:粤糖71/210经喷施草甘膦后2个月,桂糖11经喷施乙烯利后1个月,甘蔗蔗糖分分别比对照高1.45%和2.42%;PP_(333)的作用不明显。三种处理在植株株高、茎节数、节间长度、蔗产量及宿根蔗出苗数等方面,与对照无显著差别。     

Influence of compost/sludge application on sugarcane yield and nitrogen requirement on a sand soil

Mineral soils in southern Florida are very low in organic matter content and most of the nitrogen (N) for sugarcane (Saccharum spp.) must be supplied in split fertilizer applications. Information is needed regarding how the interaction of organic amendments and fertilizer N influences sugarcane yields. A field study on a sand soil (Alfisol) was established to determine (1) potential sugarcane yield benefits of a compost/sludge amendment, and (2) the influence of the amendment on N fertilizer requirement. A split-plot Latin square design was used with five N rates (main plots) and presence or absence of compost/sludge broadcast at 113 m³ ha^?1 (subplots). Annual N rates were 0, 67, 134, 202, and 269 kg N ha^?1. Compost/sludge application increased cumulative t sucrose ha^?1 by 36% averaged across N rates. The amendment also lowered annual N requirement by an average of 38%, but maintenance applications of compost/sludge will be required every four years.     

The Influence of pH and Organic Matter from Sugarcane By-products on Soil Cadmium Fractionation

ABSTRACT

Crop wastes or by-products can have the potential to be used as effective amendments to improve agricultural soil quality and/or crop yields subject to appropriate screening and testing. Sugarcane (Saccharum officinarum L.) waste by-products from an ethanol production plant, including boiler ash, filter cake, and vinasse, were applied as soil amendments at 5%, 10%, 20%, and 40% (w/w) to study the relationship between pH and organic matter (OM) on cadmium (Cd) bioavailability and adsorption via organic matter using the Cd sequential extraction procedure. Soil pH was significantly affected by aging of the treatment with boiler ash, filter cake, and vinasse. At the end of the experiment, the Cd concentrations with all treatments were mainly released in the first two extraction steps of the sequential procedure, i.e., most mobile and easily mobilized fractions. Pearson correlation analyses revealed a negative relationship between pH and bioavailable Cd and between OM and oxidizable Cd. The pH reduction induced by the amendments was a major factor affecting soil Cd bioavailability. The effect of OM on Cd fractionation could not be clearly observed and interpreted in this study.     

Biomolecular evidence for plant domestication in Sahul

The question of the introduction of domesticated plants from the Sunda plate (South-east Asia) to Sahul (New Guinea, Australia and Tasmania) has been a subject of speculation and debate for decades. This paper reviews recent phylogenetic studies conducted with biomolecular markers on bananas (Musa spp.), breadfruit (Artocarpus altilis), sugarcane (Saccharum spp.), taro (Colocasia esculenta) and the greater yam (Dioscorea alata). Biomolecular evidence for plant domestication in Sahul is presented and discussed. Biomolecular markers reveal that for these crops at least, domestication has occurred in New Guinea and further east in Melanesia. This domestication produced cultivated genotypes that were selected from the endemic wild gene pools. These areas of domestication still are important centres of diversity for crop species that also exist in Asia. For most crops, genetic distances are very important between the two gene pools due to the geographic isolation of the two continental plates. The implications of these findings have obvious bearings on genetic resources programme strategies and future surveys.     

Molecular assay of novel pasturage, sugarcane-grass 94-42, using RAPD markers

Sugarcane-grass 94-42, a novel pasturage, was derived from the cross of a sugarcane cultivar line Co419 and a wild line PT43-52 (Saccharum robustum Brand. et Jesw. ex Grassl). To assay the genetic diversity among Co419, PT43-52 and the F₁ hybrid sugarcane-grass 94-42, 67 RAPD markers were used to detect the genomes of three lines. Around 284 bands were produced by amplification of which 116 were shown to be polymorphic in three lines. Homology of the three lines was analyzed based on all bands. Results showed that the similarity coefficient between Co419 and PT43-52, PT43-52 and sugarcane-grass 94-42, and Co419 and sugarcane-grass 94-42 were 0.7658, 0.8009 and 0.9138, respectively. A total of 95.4% bands amplified from sugarcane-grass 94-42 were homologous with those from either Co419 or PT43-52, which proved that sugarcane-grass 94-42 was the filial generation of Co419 and PT43-52.     

Rapid,Wet Oxidation Procedure for the Estimation of Silicon in Plant Tissue

Abstract

The quantification of silicon (Si) in plant samples is being requested more frequently, especially in agricultural laboratories associated with the determination of nutritional requirements of sugarcane (Saccharum officinarum L.) and rice (Oryza sativa L.). The analysis of plant material for Si can be protracted, especially if laboratories do not have access to X‐ray flourescence (XRF) instrumentation and large numbers of samples are involved. A simplified procedure using equipment considered standard in most agricultural laboratories is reported. Dry, ground plant material is subjected to nitric acid/peroxide oxidation in a low‐pressure laboratory microwave digestion system. The hydrated silica liberated from the organic matrix is dissolved in a small volume of sodium hydroxide solution also using the microwave digestion system. Silicon is measured by inductively coupled plasma atomic emission spectrometry (ICP‐AES). This method gives results that are linearly correlated with the much slower conventional techniques and avoids using hazardous chemicals (hydrofluoric acid) sometimes employed in other microwave methods.