Insect feeding-induced differential expression of <Emphasis Type="Italic">Beta vulgaris</Emphasis> root genes and their regulation by defense-associated signals

Root responses to insect pests are an area of plant defense research that lacks much information. We have identified more than 150 sugar beet root ESTs enriched for genes responding to sugar beet root maggot feeding from both moderately resistant, F1016, and susceptible, F1010, genotypes using suppressive subtractive hybridization. The largest number of identified F1016 genes grouped into the defense/stress response (28%) and secondary metabolism (10%) categories with a polyphenol oxidase gene, from F1016, identified most often from the subtractive libraries. The differential expression of the root ESTs was confirmed with RT-PCR. The ESTs were further characterized using macroarray-generated expression profiles from F1016 sugar beet roots following mechanical wounding and treatment of roots with the signaling molecules methyl jasmonate, salicylic acid and ethylene. Of the examined root ESTs, 20, 17 and 11% were regulated by methyl jasmonate, salicylic acid and ethylene, respectively, suggesting these signaling pathways are involved in sugar beet root defense responses to insects. Identification of these sugar beet root ESTs provides knowledge in the field of plant root defense and will lead to the development of novel control strategies for control of the sugar beet root maggot.Electronic Supplementary Material Supplementary material is available in the online version of this article at and is accessible for authorized users     

Suitability of commercial beet molasses fractions as substrates fro polyhydroxyalkanoate production byAzotobacter vinelandii UWD

Summary Beet molasses that had been fractionated commercially by ion exclusion resulted in two waste-streams: extract molasses (EM) and concentrated separator by-product (CSB). Only EM at 4–5% w/v contained sufficient sugar to promote polyhydroxybutyrate (PHB) formation byAzotobacter vinelandii UWD, but the yield of PHB/protein was less than that obtained in unfractionated beet molasses. EM and especially CSB added at 0.5–2.0% w/v to media containing a variety of sugar sources promoted an increased yield of PHB/protein. The best use of these beet molasses fractions was, therefore, as a minor addition to media containing sugars to increase PHB yield, but not as a primary substrate for PHB production.     

Bodenbewohnende Schädlinge und Seitenwurzelfäule der Zuckerrübe in Abhängigkeit von der Rotation – Ergebnisse eines Fruchtfolgeversuches

Soil inhabiting pests and rot of feeding roots of sugar beet depending on rotation - Results of a long-term trial Over a period of 17 years a trial was carried out with sugar beet, cereals and oilseed rape in different crop rotations on a field near Göttingen (Lower Saxony). The frequency of sugar beet in the rotation was 17, 25, 33 and 67 %. In absence of beet nematodes, root and sugar yield of the beet decreased after repeated growing of sugar beet in short rotations compared to variants with long rotations. Sugar content and beet quality were only slightly influenced. By applying a bioassay (BW-Test) with young beet plants in the greenhouse it was shown that increasing infections on the tips of rootlets of the beet plants were the cause for decreasing beet yield in close rotations. Mortality of young beet plants and progress of infection in the test indicated roughly the quantity of pathogenic fungi in the soil. In the roots of the bait platits the parasitic fungus Aphanomyces cochlioides predominated. Rate of infection and yield reduction in the field were decisively influenced by weather conditions. Differences in yield between sugar beet grown in a three-year and a four-year rotation, however, were not significant. An occurrence of beet pests depending on crop rotation was stated only for Atomaria linearis and this only in a few years.     

Production of poly-b-hydroxybutyrate by Azotobacter vinelandii in a two-stage fermentation process

Poly-b-hydroxybutyrate (PHB) production in Azotobacter vinelandii UWD, a mutant that produces PHB constitutively, was suppressed by high aeration of beet molasses medium. Thus a two-stage process was designed using aeration to promote growth and suppress PHB production in the first phase, while lower aeration of raw sugar medium containing fish peptone was used to promote PHB formation in the second phase. A PHB yield of 36 g/l and productivity of > 1 g polymer l -1 .h was obtained by this approach.     

Analysis of gene inheritance and expression in hybrids between transgenic sugar beet and wild beets

Reciprocal gene exchange between cultivated sugar beet and wild beets in seed production areas is probably the reason for the occurence of weed beets in sugar beet production fields. Therefore, when releasing transgenic sugar beet plants into the environment, gene transfer to wild beets ( Beta vulgaris ssp. maritima ) has to be considered. In this study the transfer of BNYVV- (beet necrotic yellow vein virus) resistance and herbicide-tolerance genes from two transgenic sugar beet lines that were released in field experiments in 1993 and 1994 in Germany to different wild beet accessions was investigated. In order to evaluate the consequences of outcrossing, manual pollinations of emasculated wild beet plants with homozygous transgenic sugar beet plants were performed. In the resulting hybrids the transgenes were stably inherited according to Mendelian law. Gene expression in leaves and roots of the hybrids was in the same range as in the original transgenic sugar beet plants. Moreover, it was found that in one of the wild beet accessions, transfer and expression of the BNYVV resistance gene did considerably increase the level of virus resistance.     

Detection of beet yellows virus in sugar beet leaves and roots by enzyme-linked immunosorbent assay (ELISA)

Using the enzyme-linked immunosorbent assay (ELISA) beet yellows virus (BYV) could be detected reliably in the leaves of sugar beet andTetragonia expansa Pall. and in the roots of sugar beet. Specifio γ-globulin of BYV antiserum was coupled to horse radish peroxidase by periodate oxidation. Optimum dilutions of antigen (extract from infected leaves) were1: 50 to 1: 200 for BYV detection in sugar beet andT. expansa leaves and1: 2 to 1: 5 for detection in sugar beet roots. Extracts from beet roots are not to be purified by ultracentrifugation, however, by the described method virus can be demonstrated only in 80–90% of naturally infected sugar beet roots. The method is specific, no increase of extinction values was found in healthy or beet western yellows virus infected plants. Presence of virus can be demonstrated by visual as well as photometric evaluation. Results confirmed the suitability of peroxidase application for detection of plant viruses by ELISA.     

Taproot promoters cause tissue specific gene expression within the storage root of sugar beet

The storage root (taproot) of sugar beet (Beta vulgaris L.) originates from hypocotyl and primary root and contains many different tissues such as central xylem, primary and secondary cambium, secondary xylem and phloem, and parenchyma. It was the aim of this work to characterize the promoters of three taproot-expressed genes with respect to their tissue specificity. To investigate this, promoters for the genes Tlp, His1-r, and Mll were cloned from sugar beet, linked to reporter genes and transformed into sugar beet and tobacco. Reporter gene expression analysis in transgenic sugar beet plants revealed that all three promoters are active in the storage root. Expression in storage root tissues is either restricted to the vascular zone (Tlp, His1-r) or is observed in the whole organ (Mll). The Mll gene is highly organ specific throughout different developmental stages of the sugar beet. In tobacco, the Tlp and Mll promoters drive reporter gene expression preferentially in hypocotyl and roots. The properties of the Mll promoter may be advantageous for the modification of sucrose metabolism in storage roots.     

甜菜增产菌P10菌株的鉴定

在新疆甜菜块根皮层内分离并筛选到对甜菜具有增产增糖作用的优化菌株Ｐ＿（１０）。通过形态培养征和生理生化特性研究,将该菌株鉴定为短小芽孢杆菌（Ｂａｃｉｌｕｓｐｕｍｉｌｕｓ）。     

Genetic localization of four genes for nematode (Heterodera schachtii Schm.) resistance in sugar beet (Beta vulgaris L.)

Sugar beet (Beta vulgaris L.) is highly susceptible to the beet cyst nematode (Heterodera schachtii Schm.). Three resistance genes originating from the wild beets B. procumbens (Hs1 ^pro-1) and B. webbiana (Hs1 ^web-1, Hs2 ^web-7) have been transferred to sugar beet via species hybridization. We describe the genetic localization of the nematode resistance genes in four different sugar beet lines using segregating F₂ populations and RFLP markers from our current sugar beet linkage map. The mapping studies yielded a surprising result. Although the four parental lines carrying the wild beet translocations were not related to each other, the four genes mapped to the same locus in sugar beet independent of the original translocation event. Close linkage (0–4.6 cM) was found with marker loci at one end of linkage group IV. In two populations, RFLP loci showed segregation distortion due to gametic selection. For the first time, the non-randomness of the translocation process promoting gene transfer from the wild beet to the sugar beet is demonstrated. The data suggest that the resistance genes were incorporated into the sugar beet chromosomes by non-allelic homologous recombination. The finding that the different resistance genes are allelic will have major implications on future attempts to breed sugar beet combining the different resistance genes.     

Proteome analysis of sugar beet (Beta vulgaris L.) elucidates constitutive adaptation during the first phase of salt stress

Salinity is one of the major stress factors responsible for growth reduction of most of the higher plants. In this study, the effect of salt stress on protein pattern in shoots and roots of sugar beet (Beta vulgaris L.) was examined. Sugar beet plants were grown in hydroponics under control and 125 mM salt treatments. A significant growth reduction of shoots and roots was observed. The changes in protein expression, caused by salinity, were monitored using two-dimensional gel-electrophoresis. Most of the detected proteins in sugar beet showed stability under salt stress. The statistical analysis of detected proteins showed that the expression of only six proteins from shoots and three proteins from roots were significantly altered. At this stage, the significantly changed protein expressions we detected could not be attributed to sugar beet adaptation under salt stress. However, unchanged membrane bound proteins under salt stress did reveal the constitutive adaptation of sugar beet to salt stress at the plasma membrane level.     

The dynamics of hormonal status of developing red beet root (<Emphasis Type="Italic">Beta vulgaris</Emphasis> L.) in correlation with the dynamics of sugar accumulation

We studied the dynamics of phytohormone levels (indole-3-acetic acid, abscisic acid, cytokinins, and gibberellin-like substances) in red beet (Beta vulgaris L.) roots at different developmental stages in comparison with the data on the dynamics of sugar accumulation in order to test possible hormonal regulation of sugar accumulation. The obtained data suggest the involvement of cytokinins and gibberellin-like substances in the control of sugar accumulation in the roots, while indole-3-acetic acid, abscisic acid, and gibberellin-like substances can control the outflow. The data on the dynamics of phytohormone levels shed light on their specific physiological role in red beet root development.Translated from Izvestiya Akademii Nauk, Seriya Biologicheskaya, No. 1, 2005, pp. 30–35.Original Russian Text Copyright © 2005 by Ozolina, Pradedova, Salyaev.     

Chemical control of beet cyst-nematode, Heterodera schachtii, in some peaty loam soils

In peaty loam soils, aldicarb or oxamyl mixed with the top 15 cm of the soil in spring before sugar beet seeds were sown, minimised invasion of the roots by larvae of the beet cyst-nematode, Heterodera schachtii, so preventing injury to the seedlings, and greatly increased sugar yields in heavily infested soil. Small amounts of both compounds were often as effective as larger amounts. Nematode increase on sugar beet roots was slow. Aldicarb or oxamyl lessened nematode increase in four years out of five. Fumigating predetermined row positions with dichloropropene mixtures (D-D, Telone) or incorporating aldicarb or methomyl shallowly in soil, later occupied by the roots of sugar beet seedlings, did not control the nematode, although sugar yields were sometimes increased.     

Suppression of Rhizoctonia solani diseases of sugar beet by antagonistic and plant growth-promoting yeasts

AIMS: Isolates of Candida valida, Rhodotorula glutinis and Trichosporon asahii from the rhizosphere of sugar beet in Egypt were examined for their ability to colonize roots, to promote plant growth and to protect sugar beet from Rhizoctonia solani AG-2-2 diseases, under glasshouse conditions. METHODS AND RESULTS: Root colonization abilities of the three yeast species were tested using the root colonization plate assay and the sand-tube method. In the root colonization plate assay, C. valida and T. asahii colonized 95% of roots after 6 days, whilst Rhod. glutinis colonized 90% of roots after 8 days. Root-colonization abilities of the three yeast species tested by the sand-tube method showed that roots and soils attached to roots of sugar beet seedlings were colonized to different degrees. Population densities showed that the three yeast species were found at all depths of the rhizosphere soil adhering to taproots up to 10 cm, but population densities were significantly (P < 0.05) greater in the first 4 cm of the root system compared with other root depths. The three yeast species, applied individually or in combination, significantly (P < 0.05) promoted plant growth and reduced damping off, crown and root rots of sugar beet in glasshouse trials. The combination of the three yeasts (which were not inhibitory to each other) resulted in significantly (P < 0.05) better biocontrol of diseases and plant growth promotion than plants exposed to individual species. CONCLUSIONS: Isolates of C. valida, Rhod. glutinis and T. asahii were capable of colonizing sugar beet roots, promoting growth of sugar beet and protecting the seedlings and mature plants from R. solani diseases. This is the first successful attempt to use yeasts as biocontrol agents against R. solani which causes root diseases. SIGNIFICANCE AND IMPACT OF THE STUDY: Yeasts were shown to provide significant protection to sugar beet roots against R. solani, a serious soil-borne root pathogen. Yeasts also have the potential to be used as biological fertilizers.     

In vitro and in vivo antagonism of actinomycetes isolated from Moroccan rhizospherical soils against Sclerotium rolfsii: a causal agent of root rot on sugar beet (Beta vulgaris L.)

Aims:  To evaluate the ability of the isolated actinomycetes to inhibit in vitro plant pathogenic fungi and the efficacy of promising antagonistic isolates to reduce in vivo the incidence of root rot induced by Sclerotium rolfsii on sugar beet.
Methods and Results:  Actinomycetes isolated from rhizosphere soil of sugar beet were screened for antagonistic activity against a number of plant pathogens, including S.   rolfsii . Ten actinomycetes out of 195 screened in vitro were strongly inhibitory to S. rolfsii . These isolates were subsequently tested for their ability to inhibit sclerotial germination and hyphal growth of S. roflsii . The most important inhibitions were obtained by the culture filtrate from the isolates J-2 and B-11, including 100% inhibition of sclerotial germination and 80% inhibition of hyphal growth. These two isolates (J-2 and B-11) were then screened for their ability to protect sugar beet against infection of S. rolfsii induced root rot in a pot trial. The treatment of S. rolfsii infested soil with a biomass and culture filtrate mixture of the selected antagonists reduced significantly ( P  ≤ 0·05) the incidence of root rot on sugar beet. Isolate J-2 was most effective and allowed a high fresh weight of sugar beet roots to be obtained. Both antagonists J-2 and B-11 were classified as belonging to the genus Streptomyces species through morphological and chemical characteristics as well as 16S rDNA analysis.
Conclusion:  Streptomyces isolates J-2 and B-11 showed a potential for controlling root rot on sugar beet and could be useful in integrated control against diverse soil borne plant pathogens.
Significance and Impact of the Study:  This investigation showed the role, which actinomycete bacteria can play to control root rot caused by S.   rolfsii , in the objective to reduce treatments with chemical fungicides.     

Genetic approaches to sustainable pest management in sugar beet (Beta vulgaris)

Sugar beet (Beta vulgaris) is an important arable crop, traditionally used for sugar extraction, but more recently, for biofuel production. A wide range of pests, including beet cyst nematode (Heterodera schachtii), root‐knot nematodes (Meloidogyne spp.), green peach aphids (Myzus persicae) and beet root maggot (Tetanops myopaeformis), infest the roots or leaves of sugar beet, which leads to yield loss directly or through transmission of beet pathogens such as viruses. Conventional pest control approaches based on chemical application have led to high economic costs. Development of pest‐resistant sugar beet varieties could play an important role towards sustainable crop production while minimising environmental impact. Intensive Beta germplasm screening has been fruitful, and genetic lines resistant to nematodes, aphids and root maggot have been identified and integrated into sugar beet breeding programmes. A small number of genes responding to pest attack have been cloned from sugar beet and wild Beta species. This trend will continue towards a detailed understanding of the molecular mechanism of insect–host plant interactions and host resistance. Molecular biotechnological techniques have shown promise in developing transgenic pest resistance varieties at an accelerated speed with high accuracy. The use of transgenic technology is discussed with regard to biodiversity and food safety.     

Suppression of Fusarium oxysporum with recombinant polygalacturonase inhibiting proteins (BvPGIPs) extracted from sugar beet roots

Soil-borne fungus Fusarium oxysporum f. sp. betae (Fob) is the causative agent of Fusarium yellows in sugar beet. Leaf interveinal yellowing and root vascular discoloration significantly reduce root yield as well as sucrose content and juice purity. Fob, like other fungal pathogens, initiates disease development by secreting polygalacturonase (PG) enzymes to break down plant cell walls during early stages of infection. To protect themselves, plants produce polygalacturonase-inhibiting proteins (PGIPs). In our study of sugar beet root defense responses, several PGIP genes (BvPGIPs) were identified. To determine if BvPGIPs inhibit Fob PGs, genes BvPGIP1, BvPGIP2 and Bv(FC607)PGIP1 were fused with the CaMV 35S promoter and each was expressed individually in sugar beet hairy roots. We demonstrate that all three recombinant BvPGIP proteins inhibited Fob and F. oxysporum f. sp. gladioli (Fog) PGs. A comparable level of BvPGIP activity was observed against Fob PGs, while BvPGIP2 showed higher activity against Fog PGs. Similar results were obtained when recombinant PGIPs were used to bioassay effects on Fob and Fog spore germination and hyphal growth. This is a first report that documents F. oxysporum inhibition by overexpressing BvPGIPs that may lead to improved Fusarium yellows resistance in sugar beet.