Biochemical and Morphological Characteristics of Acid-Resistant Regenerants of Sugar Beet （Beta vulgaris L.）

The aim of the paper was to study the metabolite profile and morphological characteristics of sugar beet regenerants exposed to aluminium ions （Al^3＋）. The regenerants were selected basing on selective media with sublethal acidity （pH 3.5）. The thrice-repeated passaging of sugar beet microclones of two genotypes in low pH medium causes certain alterations in the cellular metabolism. The paper demonstrated that peroxidase （POD） and isocitrate lyase （ICL） activity increased in both varieties. At the same time, NADH-dehydrogenase （NADH-DH） activity decreased in hybrid plants. Glucose-6-phosphate-dehydrogenase （gl-6-ph-dh） activity increased in mail sterile （MS） hybrid plants, but reduced in Ramonskaya fertile （RF） hybrid plants. Adaptation to reduced pH was accompanied by alterations in the isozyme spectra of POD, 1- and 2-esterase, cytochrome c oxidase and malic enzyme （ME）. The adaptation process of sugar beet regenerants was also accompanied by an increase in protein synthesis. The level of metabolic response to stress very much depended on the initial genotype of the hybrid. In this experiment, aluminium resistant plants were growing rapidly in selective media. They developed leaves with healthy petioles and blades and had strong root systems.

Transcriptome analysis of sugar beet root maggot （Tetanops myopaeformis） genes modulated by the Beta vulgaris host

Sugar beet root maggot （SBRM, Tetanops myopaeformis von R6der） is a major but poorly understood insect pest of sugar beet （Beta vulgaris L.）. The molecular mecha- nisms underlying plant defense responses are well documented, however, little information is available about complementary mechanisms for insect adaptive responses to overcome host resistance. To date, no studies have been published on SBRM gene expression pro- filing. Suppressive subtractive hybridization （SSH） generated more than 300 SBRM ESTs differentially expressed in the interaction of the pest with a moderately resistant （F1016） and a susceptible （F1010） sugar beet line. Blast2GO v. 3.2 search indicated that over 40% of the differentially expressed genes had known functions, primarily driven by fruit fly D. melanogaster genes. Expression patterns of 18 selected EST clones were confirmed by RT-PCR analysis. Gene Ontology （GO） analysis predicted a dominance of metabolic and catalytic genes involved in the interaction of SBRM with its host. SBRM genes function- ing during development, regulation, cellular process, signaling and under stress conditions were annotated. SBRM genes that were common or unique in response to resistant or susceptible interactions with the host were identified and their possible roles in insect responses to the host are discussed.

A Resistance Bioassay for Rhizoctonia Root and Crown Rot and Damping-off Caused by the Anastomosis Groups AG 2-2111B and AG 4 in Sugar Beet

In order to determine the level of resistance of sugar beet varieties against Rhizoctonia solani AG 2-21IIB and AG 4, a methodology was implemented under greenhouse conditions that contemplated the most important criteria regarding to plant-pathogen interaction. The effect of plant growth stage on the development of the disease was evaluated. Seven sugar beet varieties were tested for resistance to R. solani AG 2-2IIIB and AG 4. To detect differences in leaf temperature between/L solani inoculated plants and non-infected plants, an infrared （IR） camera was tested. High incidence of R. solani AG 2-2IIIB and AG 4 in sugar beet plants was evident when the fungal inoculum was applied to two and four weeks old plants. At four weeks after sowing, it was the optimum time to inoculate sugar beet plants in order to generate R. solani infection, since at this time all plants were infected. Significant differences were detected regarding disease incidence between sugar beet varieties inoculated with different anastomosis groups. Leaf temperature was significant different between inoculated and non-inoculated plants, demonstrated that this technique could be a new tool for breeders to screen for resistance of new varieties.

Introduction of AtNHX1 into beet improved salt-tolerance of transgenic plants

AtNHX1 gene encoding the Na ^＋/H ^＋ antiport on the vacuole membrane of Arabidopsis was transferred into small bud tips of 1-3mm in length derived from immature inflorescence cultures of six genotypes of beet （ Beta vulgaris L. ） by the infection of Agrobacterium tumefaciens and transgenic plants with improved salt-tolerance were obtained. When transgenic plants at 5-leaf stage were potted in sand and irrigated with solutions containing a range of concentrations of NaCl （171-513mM）, they showed minor symptoms of damage from salinity and better tolerance than the controls. There were considerable discrepancies of salt-tolerance between transgenic plants originated from the same genotype and also between different genotypes. After vernalization, bolting transgenic plants were enveloped with two layers of gauzes for self-pollination. T1 seedlings tolerant to 342-427mM NaCl were obtained respectively. These results revealed that it was feasible to improve salt-tolerance of beets by the introduction of AtNHX1 gene into cultured bud cells.

Determination of Effective Degree-Day for Supporting Chemical Control Against Cutworms （Lep. Noctuinae） in the Sugar Beet

The aim of the research was to connect two methods of the chemical control. The first chemical treatments were applied according to the signalling method. The second method was applied according to the phonological criterion i.e., on the basis of the values of effective temperatures sums or heat sums for cutworms. The studies on cutworms infesting sugar beet crops were carried out in the years 2005-2008. The observation performed during the moth flights from May to September included two species, turnip moth （Agrotis segetum Den. ＆ Schiff.） and heart-and-dart moth （A. exclamationis L.）. The dynamics of moth flights was recorded in reference to readings of climatic conditions registered with the field meteorological stations set up near the light traps. Observations on cutworm occurrence during the vegetation season were done every 5-7 days. Moreover, additional studies were conducted under control conditions in the growth chambers at three programmed temperatures （17°C, 20 °C, 24 °C） and relative humidity （50%-70%）. Based on the results the values for the heat sum of 501.1 °C and effective temperatures sum of 230.0 °C were determined for the developmental stages of cutworm. On the base of the results obtained it can be stated that the improved method of short-term forecasting can be an alternative solution in the integrated protection management against pest.

Biodiversity Assessment of Sugar Beet Species and Its Wild Relatives:Linking Ecological Data with New Genetic Approaches

The value of crop wild relatives has long been acknowledged and this wild resource has been used to improve crop performance with clear economic benefits. Sugar beet (Beta vulgaris subsp. vulgaris) is the most economically valuable crop species in the order Caryophyllales, B. vulgaris subsp. maritima being the ancestor of the cultivated beets. The wild species of the genus Beta s.l. are commonly found in coastal areas of Europe and Mediterranean Region, where a rich genetic heritage still exists. Broadening the genetic base of sugar beet by introgression with wild relatives is a growing need regarding the maintenance of ecologically important traits. Since wild relatives have adapted to specific habitats, they constitute an important source of novel traits for the beet breeding pool. So, we conducted a broader research project aiming to delimit taxa and identify priority locations to establish genetic reserves of the wild Beta species occurring in Portugal (Western Iberian Peninsula). The aim of this study was: 1) to identify and characterize the main habitats of these wild Beta species;and 2) to present a review of some genetic tools available for future application in sugar beet breeding. In this review, we have focused on EcoTILLING as a molecular tool to assess DNA polymerphisms in wild populations of Beta and identify candidate genes related to drought and salt tolerance, as well as addressed some issues related to next-generation sequencing (NGS) technologies as a new molecular tool to assess adaptive genetic variation on the wild relatives of sugar beet.

高糖甜菜BvNHX1基因的克隆及表达特性分析

本研究以高糖甜菜品种‘BS02’为材料,采用同源克隆技术分离其液泡膜Na+/H+逆向转运蛋白基因,命名为BvNHX1。该基因包含有1 659 bp的开放阅读框,编码552个氨基酸,蛋白分子量为61.31 kD,理论等电点为6.31。预测该基因编码的蛋白具有12个跨膜结构域,同时具有Nhap、NaHExchanger和bcpa1超家族的保守结构域,而且与盐角草、犁苞滨藜、盐地碱蓬等多种藜科植物NHXs聚为一类,属于液泡膜NHX家族中的ClassⅠ成员。实时荧光定量PCR结果显示:在400 mmol/L NaCl、200 mmol/L KCl和15 mmol/L ABA处理下,该基因表达量分别在叶和根中达到峰值,且叶中的表达量均显著高于根中,表明该基因在响应NaCl、KCl和ABA时,可能在叶中发挥的作用远大于根中。本研究结果将为甜菜耐盐分子机理的研究奠定基础,同时为高糖甜菜耐盐性遗传改良提供坚实可靠的依据。

甜菜BvHKT6基因的克隆及表达模式分析

为调查甜菜高亲和性 K~+转运蛋白基因的功能,本研究从自育高糖型甜菜(‘BS02’)中分离了高亲和性 K~+转运蛋白基因,命名为 Bv HKT6。该基因包含有 1 620 bp 的开放阅读框,编码 539 个氨基酸,蛋白分子量 60.11 k D,理论等电点 9.24。生物信息学分析显示该基因编码的蛋白定位于细胞质膜,含有 8 个跨膜结构域及 4 个空隙结构域,具有 HKTs 超家族中特有的 Trk H 和 Trk G 保守结构域;该蛋白属于 HKTs 家族中的亚家族Ⅰ,并且与藜科植物如藜麦、菠菜 HKTs 的亲缘关系较近。定量 PCR 结果表明 Bv HKT6 基因能够被Na Cl、KCl 和 ABA 等诱导表达,且分别在 400 mmol/L Na Cl、200 mmol/L KCl、20 mmol/L ABA 处理下在根和叶中的表达量达到最大值。此外,在不同浓度 Na Cl 处理下,Bv HKT6 基因在根中的表达量明显高于在叶中的表达量,而在不同浓度 KCl 和 ABA 处理下,正好与之相反,表明该基因在响应不同胁迫时具有明显的组织特异性。以上研究结果为解析甜菜离子转运分子机制提供理论基础,同时为高糖甜菜的耐盐遗传改良提供候选基因。

基于限制位点相关的DNA(RAD)测序技术检测甜菜多态性

甜菜是一种重要的糖料作物,占世界糖来源的1/3。甜菜品种改良的主要障碍是其遗传变异小、遗传资源有限。在本研究中,我们使用限制性位点相关DNA (restriction-site-associated DNA, RAD)测序技术,在全基因组范围内搜寻20种甜菜基因型的SNPs和SSRs。根据有效限制性酶切片段(restriction fragment, RF)的GO注释,发现7 144个与"生物过程"有关,4 378个与"细胞组份"有关,3 763个与"分子功能"有关。采用多重比对方法,鉴定出甜菜含有38 884 682 SNP位点。这些SNP成功地揭示了甜菜基因型间的遗传关系。此外,在RAD酶切序列中也鉴定出了17 916个SSR位点。甜菜基因组中最常见的SSR序列为二核苷酸(6 019, 33.60%),其次是单核苷酸4 321 (24.11%),再次是三核苷酸3 597 (20.07%)。RAD测序技术使甜菜分子标记的快速全基因组发现成为可能。本研究所鉴定的大量SNP和SSRs位点,对构建甜菜高密度遗传连锁图谱、QTL分析、标记辅助选择和比较研究具有重要意义。