Correction to: Integrative transcriptomics reveals genotypic impact on sugar beet storability

Plant Molecular Biology - In the above mentioned publication, part of Fig. 6B was distorted (extra diagonal lines appeared). The original article has been corrected and the proper version...     

Competitiveness of transgenic sugar beet resistant to beet necrotic yellow vein virus and potential impact on wild beet populations

Beets are a crop of particular concern regarding invasiveness questions because they commonly become feral due to unintentional hybridization with annual forms of wild beets. In this study the performance of transgenic beets resistant to Beet Necrotic Yellow Vein Virus (BNYVV) was compared to the performance of unmodified material from the same breeding line. Both transgenic and control genotypes were also compared to a conventionally bred variety carrying a similar phenotypic trait. Field tests were developed in a step by step fashion in order to study seed emergence and competitiveness in early life stages. The tests quantified the potential ecological advantage of virus resistance under virus and non-virus infestation conditions. In experimental field releases in 1993 and 1994 in Germany, a small but increasingly clear 'additive' ecological advantage of the genetically engineered trait was detected. In both years and all competition treatments, the conventional tolerant variety performed best. An impact of naturalization on natural, nonagricultural habitats may appear in wild beet populations in Italian seed beet production areas. However, a survey of coastal areas of North-Eastern Italy found no virus infestation in 1994, suggesting that an increase in wild beet fitness is unlikely to occur.     

Phenotypic polymorphism and allele differentiation of isozymes in fodder beet,multigerm sugar beet and monogerm sugar beet

Summary Thirteen enzymes (MDH, SDH, LAP, PGM, PX, IDH, GPI, 6PGD, APH, GOT, GDH, ME and SOD) of 3 cultivated beet (B. vulgaris L.) gene pools, comprising 12 accessions of fodder beet, 11 of old multigerm sugar beet and 10 of modern monogerm sugar beet, were investigated using horizontal starch gel electrophoresis. Eleven accessions of primitive or wild B. vulgaris were also included for the comparison of isozymes. Variation in isozyme phenotypes was investigated to detect diversity in the three cultivated forms of beet. Phenotypic variation was observed in all except ME and SOD, which were monomorphic. A high degree of phenotypic polymorphism (Pj) was found in GDH, PGM, IDH, APH and MDH. Differences in phenotypic polymorphism in MDH, GPI and PX were recognized between fodder beet and both sugar beet groups. Average polymorphism for 13 enzymes in both sugar beets was significantly higher than that in fodder beet. For 13 enzymes, the existence of high isozyme diversity in both sugar beet gene pools was revealed. Allele frequencies in 13 alleles of five enzyme-coding loci, Lap, Px-1, Aph-1, Got-2 and Gdh-2, were investigated. New alleles, Px-1 ¹ and Got-2 ¹, were found in fodder beet accessions. No significant differences of average allele frequencies of five loci between fodder beet and both sugar beets were recognized. Several unique alleles and different isozyme phenotypes were observed in the accessions of B. vulgaris ssp. macrocarpa and ssp. adanensis. Future utilization of cultivated beet gene pools for sugar beet breeding is discussed from the viewpoint of genetic resources.     

Bird damage to sugar beet

Pest damage to sugar beet, including that by birds, has been recorded since 1957. During that time damage by rooks has decreased almost to nil, but some other bird damage has greatly increased, most probably as a result of changing agronomic practices, especially the extensive use of herbicides, the introduction of monogerm seed, and the increasing practice of ‘planting-to-a-stand’. The most severe bird damage in the spring is grazing by several species, and in early summer localized felling of plants by pheasants. Observations in the mid–1960's of causes of seedling and plant losses suggested that birds were then of minor importance; the British Sugar Corporation currently consider that birds are the most serious pest of sugar beet. The distribution of the reported damage does not seem to follow any national pattern. In small-plot field trials possible repellent materials such as anthraquinone, methiocarb or thiram, applied to seed or foliage, did not decrease the extent of grazing.     

Effects of beet cryptic virus infection on sugar beet in field trials

The effects of beet cryptic virus (BCV) infection on sugar beet crops were investigated in field trials in 1990. Two sugar beet breeding stock lines were screened for infection by BCV. Seed lots containing different proportions of seed infected with BCV1 & 2 were obtained by crossing the stock lines and used in field trials at five different sites. Five characteristics of the infected plants were assessed. BCV infection appeared to have no significant effects on the sugar beet crop at four locations which suffered from drought stress but significant effects were found at one site where the crop was grown on grade 1 land with good moisture retention properties. Root yield and sugar yield were reduced by up to 17% and 20%, respectively, by BCV infection.     

Effects of boron on nitrogen metabolism and sugar levels of sugar beet

Summary The effects of deficient and toxic levels of boron on various aspects of nitrogen metabolism in sugar beet are studied. Plant analysis shows a nitrate ion accumulation, a decrease in the activity of the nitrate reductase enzyme and a lower molybdenum absorption.The effect of boron levels on the plant and root sugar concentration has also been studied.     

Photosynthesis in sugar beet depends on root growth

Summary Sugar-beet plants, germinated in growth cabinets at 20°C and transplanted into the field after 3 weeks, developed much larger roots than plants grown from seed drilled directly into the soil. At the end of the season, the roots of transplants were 39% greater than from drilled seed—an increase of 14 m tons per hectare. The increased yield was mainly due to a sustained increase in photosynthesis because of the larger sink for carbohydrates provided by plants from the growth cabinets.     

Enzymatic hydrolysis of sugar beet pulp

Summary In order to prepare fermentable sugars from cellulosic raw materials, we have tested the effect of different pretreatments (heat, chemicals, pectinase) on enzymatic hydrolysis of sugar beet pulp. Best results (90% hydrolysis) have been obtained after heat treatment (30 mn at 120°C) with 16 IU.Fp.g^–1 of fresh pulp in 48 hours.     

Adenylate patterns of autumn-sown sugar beet differ from spring-sown sugar beet. Implications for root quality

Sugar beet ( Beta vulgaris L) is generally cultivated using two different planting and harvest patterns. In northern zones, spring sugar beet is sown in spring and harvested in autumn, whereas in subtropical latitudes, autumn sugar beet is sown in autumn and harvested in summer. The industrial quality of the root is frequently higher in spring-sown sugar beet crops. In order to explore physiological changes associated with this fact, this study has been focused on the seasonal changes of adenosine 5'-triphosphate and adenosine 5'-diphosphate levels in the storage roots of sugar beet plants, as an index of its metabolic status. The results obtained correspond to a different metabolic status of spring and autumn sugar beet at the moment of harvest. The adenylate patterns of autumn beets suggested a functional and active respiratory system. On the contrary, the patterns shown by spring beets corresponded to those we would expect to see in plants becoming dormant. The proline and glucose contents, which decrease the industrial quality of the root, and the respiratory rate measured in autumn-sown sugar beets, were nearly twice those of spring-sown sugar beets. The combination of an active respiratory system, which allows the carbohydrate catabolism and the synthesis of stress molecules, with the environmental factors at the time of the harvest, could be the underlying physiological mechanism causing some of the differences between spring- and autumn-sown sugar beet crops.     

Anaerobic digestion of sugar beet pulps

Summary Anaerobic digestion of sugar beet pulps was studied in a 70 l digestor with sequential feeding, after enzymatic hydrolysis by Trichoderma harzianum cellulases. During the 130 days feeding, 3.6 m³ of biogas were produced with an average content of 58% CH₄ from 270 l of hydrolysed pulps at 20 g VS/l. Average yield and production rate were respectively 0.67 m³/kg VS and 0.4 m³/ kg VS and 0.4 m³/m³ of digestor per day.     

Enzymic saccharification of sugar beet pulp

Culture filtrates of Talaromyces emersonii UCG 208 grown on beet pulp can convert the polysaccharide components of this agricultural waste to soluble sugars. The saccharification process is facilitated if the pulp is milled or incubated with alkali or peracetic acid before addition of enzyme. However, treatment of unmilled pulp with commercial pectinase prior to incubation with Talaromyces filtrate is also very effective; under suitable conditions, complete hydrolysis of total polysaccharides has been achieved.     

Mapping sugar beet pectin acetylation pattern

Homogalacturonan-derived partly methylated and/or acetylated oligogalacturonates were recovered after enzymatic hydrolysis (endo-polygalacturonase+pectin methyl esterase+side-chain degrading enzymes) of sugar beet pectin followed by anion-exchange and size exclusion chromatography. Around 90% of the GalA and 75% of the acetyl groups present in the initial sugar beet pectin were recovered as homogalacturonan-derived oligogalacturonates, the remaining GalA and acetyl belonging to rhamnogalacturonic regions. Around 50% of the acetyl groups present in sugar beet homogalacturonans were recovered as partly methylated and/or acetylated oligogalacturonates of degree of polymerisation 5 whose structures were determined by electrospray ionization ion trap mass spectrometry (ESI-IT-MSn). 2-O-acetyl- and 3-O-acetyl-GalA were detected in roughly similar amounts but 2,3-di-O-acetylation was absent. Methyl-esterified GalA residues occurred mainly upstream 2-O-acetyl GalA. Oligogalacturonates containing GalA residues that are at once methyl- and acetyl-esterified were recovered in very limited amounts. A tentative mapping of the distribution of acetyl and methyl esters within sugar beet homogalacturonans is proposed. Unsubstituted GalA residues are likely to be present in limited amounts (approximately 10% of total GalA residues), due to the fact that methyl and acetyl groups are assumed to be most often not carried by the same residues.     

Production of regenerants in sugar beet

The experimental results are presented on production of plants-regenerants of the sugar beet (Beta vulgaris L.) via callus formation or direct organogenesis from the leaf tissues. The method of aseptic treatment was developed for the seeds with strong bacterial and fungal invasion. The regenerant plants were obtained in the presence of various concentrations of synthetic hormones, such as cytokinin (6-benzaminopurine) and auxin (naphthylacetic acid), and inhibitor of auxin transport in plants (2,3,5-triiodobenzoic acid). This combination of growth regulators made it possible to avoid callus formation. The genotype of initial plants affected the capacity for callus formation and regeneration. The temperature influenced rhizogenesis in regenerants.     

Volatile components of sugar beet leaves

Extracts of both young and old sugar beet plants were obtained using a modified Likens and Nickerson apparatus. Constituents were identified by GC/MS, and using selected ion monitoring it was shown that the previously determined phenylacetonitrile was probably not of glucosinolate origin. Some unsaturated aldehydes, alcohols and derivatives (enzymic lipid degradation products) were formed to greater extents by the younger leaves, but otherwise such quantitative differences were relatively few and generally random. An interesting range of chlorinated compounds was obtained only from the older plants; a pesticide origin is suggested.     

Anaerobic biodegradation of sugar beet pulp

Sugar beet pulp is a by-product of sugar production and consists mainly of cellulose, hemicellulose and pectin. Its composition is suitable for biological degradation. A possible alternative for the utilization of this material (besides cattle feeding) can be anaerobic methanogenic degradation. It has an additional advantage – biogas production. Beet pulp was treated by a two-step anaerobic process. The first step consisted of hydrolysis andacidification. The second step was methanogenesis. In this paper, observation ofthe process of anaerobic degradation and determination of optimal parameters is discussed. A laboratory-scale model for sugar beet pulp anaerobic biodegradation was operated. Results of model performance have shown very good pulp digestion characteristics. In addition, high efficiency removal of organic matter was achieved. Methane yield was over 0.360 m³ kg^-1 dried pulp and excess sludge production was 0.094 g per gram COD added.