Physiological and genetic aspects of a diploid potato population in the Netherlands and Northern Finland

Tuberization of potatoes exposed to different photoperiod regimes has been earlier investigated in several studies. However, there is still a limited understanding of the entire tuberization process and the factors influencing this process. One of the constraints of the previous studies has been the use of only one or a few genotypes. Furthermore, the experimental designs have not utilised the natural growing conditions with continuous changes in daylength during the growing season. The general aim of the project was to study the developmental dynamics of the broad-based potato (Solanum tuberosum L.) (CxE) population development at different climatical regimes under the very long-day, long-day and short conditions in Finland, the Netherlands and Ecuador/Venezuela, respectively. In this paper we are presenting some of the results achieved in the studies in Finland during the growing season 2004. In addition to population level trait characteristics we also describe here some of the identified QTLs (quantitative trait loci) for stolon related and tuber formation traits. In some cases we also compare the expression of some of the traits both in Finland and Netherlands.The main difference between the CxE population grown in Finland and the Netherlands was that the onset of flowering took place one week later in Finland. The relationship between tuber initiation and onset of flowering differed depending on the day length. In Finland approximately 70 % of the genotypes had swollen stolon tips before the onset of flowering, while in the Netherlands only 30 % of the genotypes had reached this condition. We also found numerous different trait linked QTLs, for example, a QTL associated with tuber formation was identified on chromosome E5, and QTLs associated with stolon characteristics on chromosomes E1, E4, E10 and E12. As a conclusion, the present preliminary results provide a good basis for determining the influence of different environmental conditions on potato development. In addition, the QTLs obtained in this study give a better understanding of the genetics of complex characters, and can be used in improving the potato crop in breeding programs

A SQUAMOSA MADS-box gene involved in the regulation of anthocyanin accumulation in bilberry fruits

Anthocyanins are important health promoting phytochemicals that are abundant in many fleshy fruits. Bilberry (Vaccinium myrtillus L.) is one of the best sources of these compounds. Here we report on the expression pattern and functional analysis of a SQUAMOSA (SQUA) class MADS-box transcription factor, VmTDR4, associated with anthocyanin biosynthesis in bilberry. Levels of VmTDR4 expression were spatially and temporally linked with colour development and anthocyanin-related gene expression. Virus induced gene silencing (VIGS) was used to suppress VmTDR4 expression in bilberry resulting in substantial reduction in anthocyanin levels in fully ripe fruits. Chalcone synthase was used a positive control in the VIGS experiments. Additionally, in sectors of fruit tissue in which the expression of the VmTDR4 gene was silenced, the expression of R2R3 MYB family transcription factors related to the biosynthesis of flavonoids were also altered. We conclude that VmTDR4 plays an important role in the accumulation of anthocyanins during normal ripening in bilberry; probably through direct or indirect control of transcription factors belonging to the R2R3 MYB family

Phenolic compounds and expression of 4CL genes in silver birch clones and Pt4CL1a lines

A small multigene family encodes 4-coumarate:CoA ligases (4CLs) catalyzing the CoA ligation of hydroxycinnamic acids, a branch point step directing metabolites to a flavonoid or monolignol pathway. In the present study, we examined the effect of antisense Populus tremuloides 4CL (Pt4CL1) to the lignin and soluble phenolic compound composition of silver birch (Betula pendula) Pt4CL1a lines in comparison with non-transgenic silver birch clones. The endogenous expression of silver birch 4CL genes was recorded in the stems and leaves and also in leaves that were mechanically injured. In one of the transgenic Pt4CL1a lines, the ratio of syringyl (S) and guaiacyl (G) lignin units was increased. Moreover, the transcript levels of putative silver birch 4CL gene (Bp4CL1) were reduced and contents of cinnamic acid derivatives altered. In the other two Pt4CL1a lines changes were detected in the level of individual phenolic compounds. However, considerable variation was found in the transcript levels of silver birch 4CLs as well as in the concentration of phenolic compounds among the transgenic lines and non-transgenic clones. Wounding induced the expression of Bp4CL1 and Bp4CL2 in leaves in all clones and transgenic lines, whereas the transcript levels of Bp4CL3 and Bp4CL4 remained unchanged. Moreover, minor changes were detected in the concentrations of phenolic compounds caused by wounding. As an overall trend the wounding decreased the flavonoid content in silver birches and increased the content of soluble condensed tannins. The results indicate that by reducing the Bp4CL1 transcript levels lignin composition could be modified. However, the alterations found among the Pt4CL1a lines and the non-transgenic clones were within the natural variation of silver birches, as shown in the present study by the clonal differences in the transcripts levels of 4CL genes, soluble phenolic compounds and condensed tannins

Nurmirehu helpommin sulavaksi: sekundaarisoluseinän syntymisen säätely

Ligniini, fenoliyksiköistä koostuva verkkomainen puuaine, kertyy seinäsokeripolymeerien väliin kuolleidentuki- ja vettäkuljettavien solujen kehityksen loppuvaiheessa. Ligniini liimaa seinäpolysakkaridityhteen: soluseinistä tulee vahvoja ja vettäläpäisemättömiä. Ligniinialayksiköiden väliset ristisidoksetovat kestäviä ja niitä on erittäin vaikea hajottaa. Eri kasviryhmien seinäkoostumukset eroavat ligniinimääränja -laadun suhteen. Heinäkasvien ligniini koostuu G-, S- ja H-yksiköistä, lisäksi soluseinäsokereihinon liittynyt fenolihappoja (ferula- ja kumarihappo), joiden muodostamat ristisidokset edelleentiivistävät soluseinärakennetta. Ligniinin suuri määrällinen lisäys liittyy heinien korsiintumiseen.Tällöin korren ulompien osien solujen soluseinät paksunevat ja puutuvat, muodostuu ns. sklerenkyymituppi.Ligniini estää märehtijän ruoansulatusentsyymien pääsyä seinäpolysakkaridien luo ja tätenvähentää kasviaineksen hajoamista eläimen ruoansulatuksessa. Osa kasvin sisältämästä energiasta jäähyödyntämättä. Rehun D-arvo, joka kertoo sulavuudesta, laskee huomattavasti ligniinimäärän lisääntyessä.Sekundaariseinän biosynteesin geenitason säätelytekijöitä on selvitetty mm. mallikasvina käytetyllälituruoholla (Arabidopsis thaliana) ja puuvartisilla kasveilla (esim. poppeli ja eukalyptus). Eri säätelytekijätohjaavat sekundaariseinän kehitystä lituruohon tukisoluissa kuin vettäkuljettavissa putkisoluissaja putkiloissa. MTT:n sekä Helsingin ja Oulun yliopistojen yhteistyötutkimuksessa pyrimme selvittämään,miten sekundaarisoluseinän biosynteesiä säädellään timoteillä, Suomessa yleisesti viljellyllärehukasvilla. Tietoa säätelytekijöistä hyödynnetään selvitettäessä soluseinän lignifikaation yhteyttätimotein kehitykseen sekä rehun sulavuuteen. Tavoitteenamme on saada tietoa ligniinin biosynteesistäsekä löytää ligniinin syntyä ohjaavia säätelytekijöitä, jotka säätelevät ligniinisynteesiä erityisesti korrensklerenkyymitupessa. Tämä mahdollistaisi lähestymistavan, jossa pyrimme alentamaan ligniiniinmäärää korren uloimman osan tukisolukossa. Näin korren kokonaisligniinipitoisuus alenisi johtojänteenvedenkuljetuksen siitä kärsimättä. Kokonaisligniinimäärän lasku puolestaan parantaisi kasvimassansulavuutta. On kuitenkin huomioitava, ettei ligniinimäärän alentaminen korren tukisolukossa johdalakoontumisen lisääntymiseen tai patogeenikestävyyden alenemiseen.Yhden prosenttiyksikön muutos koko Suomen säilörehusadon D-arvossa on laskennalliselta arvoltaann. 11–17 M€/v; rohkeampien laskelmien mukaan jopa 50 M€/v (P. Virkajärvi, arvio). Tältä pohjaltaarvioiden hanke on hyvin tärkeä maidon- ja lihantuotannon säilymiselle varteenotettavana elinkeinona.Loppukädessä hyötyjänä on sekä alkutuotanto ja sen varaan perustuva kotimainen elintarvikkeitajalostava teollisuus, jonka työpaikoista noin 80 % on maidon- ja lihanjalostuksessa. Myös maataloudenpanosteollisuus on pitkälti riippuvainen märehtijöihin perustuvasta tuotannosta

Expression of Multiple Resistance Genes Enhances Tolerance to Environmental Stressors in Transgenic Poplar (Populus × euramericana ‘Guariento’)

Commercial and non-commercial plants face a variety of environmental stressors that often cannot be controlled. In this study, transgenic hybrid poplar (Populus × euramericana ‘Guariento’) harboring five effector genes (vgb, SacB, JERF36, BtCry3A and OC-I) were subjected to drought, salinity, waterlogging and insect stressors in greenhouse or laboratory conditions. Field trials were also conducted to investigate long-term effects of transgenic trees on insects and salt tolerance in the transformants. In greenhouse studies, two transgenic lines D5-20 and D5-21 showed improved growth, as evidenced by greater height and basal diameter increments and total biomass relative to the control plants after drought or salt stress treatments. The improved tolerance to drought and salt was primarily attributed to greater instantaneous water use efficiency (WUEi) in the transgenic trees. The chlorophyll concentrations tended to be higher in the transgenic lines under drought or saline conditions. Transformed trees in drought conditions accumulated more fructan and proline and had increased Fv/Fm ratios (maximum quantum yield of photosystem II) under waterlogging stress. Insect-feeding assays in the laboratory revealed a higher total mortality rate and lower exuviation index of leaf beetle [Plagiodera versicolora (Laicharting)] larvae fed with D5-21 leaves, suggesting enhanced insect resistance in the transgenic poplar. In field trials, the dominance of targeted insects on 2-year-old D5-21 transgenic trees was substantially lower than that of the controls, indicating enhanced resistance to Coleoptera. The average height and DBH (diameter at breast height) of 2.5-year-old transgenic trees growing in naturally saline soil were 3.80% and 4.12% greater than those of the control trees, but these increases were not significant. These results suggested that multiple stress-resistance properties in important crop tree species could be simultaneously improved, although additional research is needed to fully understand the relationships between the altered phenotypes and the function of each transgene in multigene transformants

Targeted plant improvement through genome editing: from laboratory to field

This review illustrates how far we have come since the emergence of GE technologies and how they could be applied to obtain superior and sustainable crop production. The main challenges of today's agriculture are maintaining and raising productivity, reducing its negative impact on the environment, and adapting to climate change. Efficient plant breeding can generate elite varieties that will rapidly replace obsolete ones and address ongoing challenges in an efficient and sustainable manner. Site-specific genome editing in plants is a rapidly evolving field with tangible results. The technology is equipped with a powerful toolbox of molecular scissors to cut DNA at a pre-determined site with different efficiencies for designing an approach that best suits the objectives of each plant breeding strategy. Genome editing (GE) not only revolutionizes plant biology, but provides the means to solve challenges related to plant architecture, food security, nutrient content, adaptation to the environment, resistance to diseases and production of plant-based materials. This review illustrates how far we have come since the emergence of these technologies and how these technologies could be applied to obtain superior, safe and sustainable crop production. Synergies of genome editing with other technological platforms that are gaining significance in plants lead to an exciting new, post-genomic era for plant research and production. In previous months, we have seen what global changes might arise from one new virus, reminding us of what drastic effects such events could have on food production. This demonstrates how important science, technology, and tools are to meet the current time and the future. Plant GE can make a real difference to future sustainable food production to the benefit of both mankind and our environment.European Cooperation in Science and Technology (COST) CA18111info:eu-repo/semantics/publishedVersio