Kései szárazságtűrésben szerepet játszó génjelöltek asszociációs vizsgálata árpában EcoTILLING módszerrel = Association testing of barley candidate genes for terminal drought tolerance using EcoTILLING technology

Célunk a szárazságtűrésben szerepet játszó kandidátus gének genetikai variabilitásának feltárása volt, melyhez az EcoTILLING módszert alkalmaztuk. Vizsgálatainkhoz a világ számos pontjáról gyűjtött 96 genotípust tartalmazó, szárazságtűrés szempontjából variábilis árpa kollekciót állítottunk össze. Az alkalmazott technológia segítségével mintegy 1,5 millió bázispárnyi szekvencia vizsgálata nyomán 94 egyedi allélvariánst különítettünk el a 9 génre tervezett 18 amplikon elemzése útján. Egy bázispárnyi eltérést (SNP) 185, inszerció/deléció-t (INDEL) pedig 46 esetben azonosítottunk. A haplotípus-szekvenciák birtokában 4 kandidátus gén esetében olyan informatív polimorfizmusokat konvertáltunk át genetikai markerekké, melyek által lehetővé vált a valószínűsíthetően funkcionális allélvariánsok elkülönítése. A szárazságtolerancia mértékének komplex stressz diagnosztikai rendszerben történő teszteléséhez összeállítottunk egy 25 genotípust tartalmazó árpa törzskollekciót. A genotípusok szárazság toleranciájának szintjét szántóföldi körülmények között is meghatároztuk. A gyökérnövekedési paraméterek nyomonkövetésére kidolgoztunk egy kísérleti rendszert. Az osztódásban lévő sejtek arányát 5-etinil-2-deoxiuridin (EdU)-re alapozott fluoreszcens mikroszkópiával határoztuk meg. Egy ellenálló és egy érzékeny genotípus esetében a génexpressziós mintázatokat is összehasonlítjuk a gyökérspecifikus és a sejtciklusban szereplő gének vizsgálata útján. | We aim for exploring genetic variability of drought tolerance related candidate genes we have applied a high throughput and relatively inexpensive method namely EcoTILLING as a polymorphism discovery tool. We have established a set of 96 barley genotypes, which contains drought tolerant and sensitive genotypes collected worldwide. By using this method approximately 1.5 million basepairs in barley a total number of 94 verified unique haplotypes were identified in 18 amplicons designed for 9 genes. Overall, 185 single nucleotide polymorphisms (SNPs) and 46 insertions/deletions (INDELs) were detected. Based on overlapping haplotype sequences, of four candidate genes informative poly-morphisms were converted into genetic markers allowing the detection of the potential functional haplotypes. To test drought tolerance and agronomic parameters we have used a complex stress diagnostic system for characterization a subcollection of 25 barley genotypes. The drought tolerance of these genotypes was also tested under field conditions. The two test system provided overlapping ranks of genotypes in drought response. We have developed an experimental system for the detection of changes of root growth parameters of barley seedlings under water deficit. The frequency of S-phase cells was detected by 5-ethynil-2-deoxiuridine (EdU) based fluorescent microscopy. By studies on tolerant and sensitive genotypes we compare gene expression profiles for root specific and cell cycle genes

Identification of genes preferentially expressed in wheat egg cells and zygotes

Wheat genes differentially expressed in the egg cell before and after fertilization were identified. The data support zygotic gene activation before the first cell division in wheat. To have an insight into fertilization-induced gene expression, cDNA libraries have been prepared from isolated wheat egg cells and one-celled zygotes. Two-hundred and twenty-six egg cell and 253 zygote-expressed EST sequences were determined. Most of the represented transcripts were detected in the wheat egg cell or zygote transcriptome at the first time. Expression analysis of fourteen of the identified genes and three controls was carried out by real-time quantitative PCR. The preferential expression of all investigated genes in the female gametophyte-derived samples (egg cells, zygotes, two-celled proembryos, and basal ovule parts with synergids) in comparison to the anthers, and the leaves were verified. Three genes with putative signaling/regulatory functions were expressed at a low level in the egg cell but exhibited increased (2-to-33-fold) relative expression in the zygote and the proembryo. Genes with high EST abundance in cDNA libraries exhibited strong expression in the egg cell and the zygote, while the ones coding for unknown or hypothetical proteins exhibited differential expression patterns with preferential transcript accumulation in egg cells and/or zygotes. The obtained data support the activation of the zygotic genome before the first cell division in wheat

Identification of genes preferentially expressed in wheat egg cells and zygotes

Wheat genes differentially expressed in the egg cell before and after fertilization were identified. The data support zygotic gene activation before the first cell division in wheat. To have an insight into fertilization-induced gene expression, cDNA libraries have been prepared from isolated wheat egg cells and one-celled zygotes. Two-hundred and twenty-six egg cell and 253 zygote-expressed EST sequences were determined. Most of the represented transcripts were detected in the wheat egg cell or zygote transcriptome at the first time. Expression analysis of fourteen of the identified genes and three controls was carried out by real-time quantitative PCR. The preferential expression of all investigated genes in the female gametophyte-derived samples (egg cells, zygotes, two-celled proembryos, and basal ovule parts with synergids) in comparison to the anthers, and the leaves were verified. Three genes with putative signaling/regulatory functions were expressed at a low level in the egg cell but exhibited increased (2-to-33-fold) relative expression in the zygote and the proembryo. Genes with high EST abundance in cDNA libraries exhibited strong expression in the egg cell and the zygote, while the ones coding for unknown or hypothetical proteins exhibited differential expression patterns with preferential transcript accumulation in egg cells and/or zygotes. The obtained data support the activation of the zygotic genome before the first cell division in wheat

Antisense inhibition of myoD expression in regenerating rat soleus muscle is followed by an increase in the mRNA levels of myoD, myf-5 and myogenin and by a retarded regeneration

It has been reported that muscles of myoD -/- mice present a lower potential to regenerate, but there are no reports on the effect of acute interference with myoD expression limited in space and time to only a particular regenerating muscle. Here we relied on antisense inhibition of this factor. Four different oligos were tested. The suppression of regeneration indices (the expression of desmin, the formation of myotubes and the initiation of endplates) was the most pronounced, with the oligomer targeting a region encompassing the translation start site of myoD. A mixed backbone phosphorothiciate-phosphate diester oligo (200 mul at 20 muM) was still detectable in the muscles I h after its administration and reverse transcription-polymerase chain reaction (RT-PCR) analysis showed that the level of the targeted 5' end of the myoD mRNA was selectively decreased. The level of myoD protein was also lowered. Four hours after the antisense treatment, when the oligos were no longer detectable, the myoD mRNA level was restored and 24 h later it exceeded controls together with that of myf-5 and myogenin. After 4 weeks, the antisense-treated soleus muscles were similar to the control-treated and the untreated regenerated soleus with respect to fiber types and motor endplates, however, they contained smaller fibers which reflected the asynchronity of regeneration. This shows that successfully targeted simple antisense oligonucleotides can be used as selective tools for inhibition of individual factors in studying the process of muscle regeneration. (C) 2002 Elsevier Science B.V All rights reserved