马铃薯地上部绿色组织中糖苷生物碱合成调控的研究

为提高马铃薯品种(系)地上部分糖苷生物碱(SGAs)的含量,增强其抗逆性并改良块茎的品质。克隆了马铃薯茄啶鼠李糖基转移酶基因(sgt3)cDNA和1,5–二磷酸核酮糖羧化酶小亚基基因启动子(rbcS P);对sgt3亚细胞定位预测显示,该蛋白不具有叶绿体转运肽、线粒体导肽和分泌信号肽序列,推测可能位于细胞质;将克隆的sgt3 cDNA片段及rbcS重组到pCEPSP载体上,构建了具有草甘膦抗性标记的绿色组织特异表达sgt3基因植物表达载体。通过农杆菌介导法对马铃薯品种‘陇薯3号’和‘夏波蒂’进行转化,共获得了12株抗草甘膦的阳性转基因植株。对转基因植株的目的基因表达水平和SGAs含量分析发现,地上部sgt3基因相对表达量较未转化植株提高1.3~3.0倍,SGAs含量增加20%~37%,而转基因植株的块茎中SGAs含量变化不显著。本研究的结果为进一步培育枝、叶中高SGAs而块茎中低SGAs的马铃薯抗性品种提供了理论依据。     

Potato germplasm development for warm climates: genetic enhancement of tolerance to heat stress

Complex potato hybrids were derived through unilateral sexual polyploidization between Solanum tuberosum cv. Atlantic and 11 diploid hybrids that produced 2n pollen through co-orientation of second division spindles. The hybrids represented the following genomic compositions: TAPB, TAPC, and TAPM where T = S. tuberosum, A = S. andigena, P = S. phureja, B = S. berthaultii, C = S. chacoense, and M = S. microdontum. The B, C, and M components of the hybrids had been selected from heat tolerant accessions. The heat tolerance and agronomic performance of the hybrids were assessed under both controlled environments and field tests. The hybrids exhibited good tuberization potential (tuber number, tuber weight and percent plants producing tubers) under heat stress conditions in controlled environments. Under severe heat stress conditions in the field in Israel, many of the hybrids tuberized when Atlantic failed to produce any tubers at all. Under more moderate heat stress in Virginia, the complex hybrids exhibited total tuber yield not significantly different from Atlantic, although the tuber set per plant was greater. However, the complex hybrids were more tolerant to heat necrosis and hollow heart than Atlantic. Total glycoalkaloids in field-grown tubers did not exceed the acceptable limit for 13 of 26 selections examined. This revised version was published online in July 2006 with corrections to the Cover Date.     

In vitro antimicrobial activity of different accessions ofSolanum commersonii Dun. from Uruguay

Summary The in vitro antimicrobial activity of extracts from accessions ofSolanum commersonii Dun. collected in the south of Uruguay was investigated against five microorganisms including the pathogenRalstonia solanacearum. A total of 30 extracts corresponding to organic and aqueous extracts were studied. Interestingly, most of the positive results for growth inhibition were againstR. solanacearum. The extracts were also analyzed for the presence of glycoalkaloids and lectins. Six of the ten aqueous extracts showed lectin presence and a wide variation in the type and amounts of glycoalkaloids, was found. Results indicate that there is no clear relationship between the antimicrobial activity against the five microorganisms screened and the presence or amounts of lectins and glycoalkaloids, traditionally regarded as possible antimicrobial metabolites in theSolanum genus, which indicates the presence of as yet unidentified antimicrobial compounds.     

Development, growth and chemical composition of the potato crop (solanum tuberosum L.). II. Tuber and whole plant

Summary This second paper of the review describes the development of the potato tuber and whole plant based on research data and literature. The development and growth, daily changes of fresh and dry matter, and of the contents of organic and inorganic components (dry matter, starch, sugars, organic acids, ascorbic acid, nitrogenous compounds, nitrate, crude lipid, glycoalkaloids, P, K, Ca, Mg, Mn, Na), discolouration indices, and physiological parameters (rate of assimilation and respiration, activity of enzymes) are reviewed.     

Inheritance of steroidal glycoalkaloids in potato tuber flesh

Potato(Solanum tuberosum L.) is the third most important food crop worldwide after wheat and rice in terms of human consumption. A critical domestication trait for potato was the decrease of toxic steroidal glycoalkaloids(SGAs) in tuber flesh. Here, we used a diploid F_2 segregating population derived from a cross between S. tuberosum and the wild potato species Solanum chacoense to map the quantitative trait loci(QTLs) associated with the regulation of SGAs content in tuber flesh. In a three-year study, we identified two QTLs on chromosomes 2 and 8 affecting SGAs content in tuber flesh. The QTL on chromosome 8 harbors 38 genes that are co-expressed with the GLYCOALKALOID METABOLISM genes. These findings lay the foundation for exploiting the genes controlling SGAs content in tuber flesh and they provide a theoretical basis for the use of wild germplasm in potato breeding.     

Determination of the glycoalkaloids α-solanine and α-chaconine levels in 18 varieties of potato (Solarium tuberosum L.) grown in Oman

Summary The glycoalkaloid content in 18 potato varieties grown in Oman was measured by HPLC using peel and flesh tissues. The total glycoalkaloid content of the tubers was found to be variety dependent and varied greatly between the 18 varieties. The total glycoalkaloid in the tubers of seven varieties was within the safe limit of ≤200 mg kg^{− 1} FW recommended for food safety, whereas the remaining 11 varieties exceeded this upper limit. The principal glycoalkaloids α-chaconine and σ-solanine were present in higher concentration in the peel than in the flesh of all varieties with the former being the principal alkaloid in the peel. The flesh of all of the 18 potato varieties contained total glycoalkaloid levels lower than the upper safety limit. The leaves of the 18 potato varieties were also analyzed for glycoalkaloids. The levels of glycoalkaloids in expanding leaves were higher than that of expanded leaves with the exception of six varieties. The principal glycoalkaloid in expanding and expanded leaves was α-chaconine. No correlation was observed between the glycoalkaloids levels of in the leaves and tubers.     

Development, growth and chemical composition of the potato crop (Solanum tuberosum L.). I. leaf and stem

Summary In this first part of a review the development of the potato leaf and stem is described, based on research data and literature. The development over time, the daily changes of fresh and dry matter, the contents of organic and inorganic components (dry matter, starch, sugars, organic acids, ascorbic acid, nitrogenous compounds, nitrate, glycoalkaloids, chlorophyll, P, K, Ca, Mg, Mn, Na, trace elements), and physiological parameters (rate of assimilation and photosynthesis, activity of enzymes) of the leaf and stem are described and discussed for every phenological growth stage of the potato crop.     

The effects of feeding diets containing potato protein concentrate on reproductive performance of rats and quality of the offspring

Two diets containing either soybean meal (SBM) or SBM and potato protein concentrate (PPC) in proportion of protein 1:1 (diet BS and BPP, respectively), were fed each to 22 females and 22 males from the age of 4-5 weeks throughout two reproductive cycles. A commercial closed-formula SNF diet containing unknown amount of potato protein was fed till the end of the first reproductive cycle. All three diets were also fed during 21 days following weaning, each to 10 offspring males born in the first cycle. The solanidine glycoalkaloids (GA) content in PPC was 2316 mg/kg DM. Feeding diets containing potato protein did not affect pregnancy rate, number and conformation of neonates and number of pups weaned (in all litters number of neonates left with dams being reduced to eight) but it depressed their body weight (weight of weaners on BPP diet only in the first cycle). Growth rate of the offspring males did not differ but feed intake was lower and feed conversion was higher on BPP than on BS and SNF diets. Feeding of BPP diet to offspring did not affect mass of body organs but increased blood urea and albumin concentrations while feeding SNF diet increased relative weight of small intestine and liver and raised blood concentrations of alanine amino transferase, albumin, protein, urea and cholesterol. In dams sacrificed after two cycles only relative weight of uterus and ovaries were lower in females fed on BPP than on BS diet. It is concluded that feeding moderate amounts (6.4%) of high-GA PPC does not impair reproductive performance, does not induce malformation of pups but depresses foetal and postnatal growth rate till weaning but not after weaning.     

α-Tomatine and other steroidal glycoalkaloids in fruits of tomato lines resistant to the glasshouse whitefly (Trialeurodes vaporariorum Westw.)

Summary The total steroidal alkaloid compositions of the mature-harvested fruits of the tomato cultivar Allround (Lycopersicon esculentum), of the species L. hirsutum glabratum, resistant to the glasshouse whitefly (Trialeurodes vaporariorum), and of four resistant lines were determined by capillary gas chromatography. The contents of -tomatine in the red-ripe fruits of Allround and in those of the lines were low (5 mg/kg fresh weight). The green-mature fruits of the wild species had a high content (3390 mg/kg fresh weight) of -tomatine. The total alkaloid profiles of Allround and of the lines were similar. Comparison of flame ionisation detector response with thermoionic detector response indicated that in addition to tomatidine, the aglycone of -tomatine, a small amount of one other steroidal alkaloid might be present in Allround and in the lines. The wild species contained five compounds which possibly are steroidal alkaloids.The safety level of -tomatine in tomatoes is discussed. It was concluded that, in respect of the glycoalkaloids of the mature-harvested fruits, the resistant tomato breeding lines are as safe for human cosumption as the standard cultivar.     

Genetic characterisation of tetraploid potato (Solanum tuberosum L.) emphasising genetic control of total glycoalkaloid content in the tubers

Two segregating resource populations were constructed, one of 216 clones using the tetraploid clones Cara and LT7 as parents and one of 176 clones using the tetraploid clones NT8 and LT7 as parents. The populations were used, in replicates, to estimate genetic parameters for total glycoalkaloid (TGA) content in the tubers, and for other agronomic and morphological traits such as tuber weight, dormancy and plant height. In both populations, the parental clones differed markedly in TGA-content and the progeny population was normally distributed for this trait after logarithmic transformation. Broad sense heritability estimate of TGA-content was 0.54 in Cara × LT7 and 0.50 in NT8 × LT7 and the trait proved to be inherited in a non-dominant manner. The minimum number of genes contributing to TGA-content was estimated to be between 3 and 7. None of the other traits recorded in this study showed a statistically significant genetic association with TGA-content. This suggests that tuber TGA-content may be genetically modulated without any significant adverse effects on other agronomic traits. The genetic parameters estimated in this study indicate that these populations are suitable for DNA-marker analysis for TGA-content in tubers. This revised version was published online in August 2006 with corrections to the Cover Date.