RESUMO
Various pea cultivars, lines, and mutants were studied by the RAPD method. Polymorphic fragments characteristic of certain pea genotypes and which can be used for identifying genotypes were detected. Inheritance of some polymorphic RAPD fragments was studied. Mendelian inheritance of these fragments was shown. By analyzing the data obtained in studies of RAPD polymorphism, genetic distances between different pea cultivars, lines, and mutants were calculated and a genealogic dendogram showing a varying extent of differences between RAPD patterns was constructed. Ten new RAPD markers linked to various pea genes were detected. Genetic distances between RAPD markers and genes to which they are linked were calculated, and the respective disposition of RAPD markers on chromosomes was established.
Assuntos
Mapeamento Cromossômico , Genoma de Planta , Pisum sativum/genética , Polimorfismo Genético , Técnica de Amplificação ao Acaso de DNA Polimórfico , DNA de Plantas/genética , Filogenia , Especificidade da EspécieRESUMO
The authors' studies on the organization and variation of plant genome with the use of molecular markers are briefly reviewed with special emphasis on random amplified polymorphic DNA (RAPD), inter simple sequence repeat (ISSR), sequence characterized amplified region (SCAR), and cleaved amplified polymorphic sequence (CAPS) markers detected with the use of polymerase chain reaction (PCR). These markers have been demonstrated to be promising for identifying cultivars and determining the purity of genetic strains of pea. Genetic relationships between strains, cultivars, and mutants of pea have been studied. The role of molecular markers in molecular genetic mapping and localizing the genes of commercially important characters of pea has been shown. The possibility of the use of molecular markers for studying somaclonal variation and detecting mutagenic factors in plants during long-term spaceflights is considered. The prospects of using DNA markers for understanding the organization and variability of higher plant genomes are discussed.
RESUMO
Received Revision received We investigated the CN--induced apoptosis of guard cells in epidermal peels isolated from pea (Pisum sativum L.) leaves. This process was considerably stimulated by illumination and suppressed by the herbicides DCMU (an inhibitor of the electron transfer between quinones Q(A) and Q(B) in PS II) and methyl viologen (an electron acceptor from PS I). These data favor the conclusion drawn by us earlier that chloroplasts are involved in the apoptosis of guard cells. Pea mutants with impaired PS I (Chl-5), PS II (Chl-I), and PS II + PS I (Xa-17) were tested. Their lesions were confirmed by the ESR spectra of Signal I (oxidized PS I reaction centers) and Signal II (oxidized tyrosine residue Y(D) in PS II). Destruction of nuclei (a symptom of apoptosis) and their consecutive disappearance in guard cells were brought about by CN- in all the three mutants and in the normal pea plants. These results indicate that the light-induced enhancement of apoptosis of guard cells and its removal by DCMU are associated with PS II function. The effect of methyl viologen preventing CN--induced apoptosis in wild-type plants was removed or considerably decreased upon the impairment of the PS II and/or PS I activity.
Assuntos
Apoptose/fisiologia , Cloroplastos/fisiologia , Fotossíntese/fisiologia , Complexo de Proteína do Fotossistema I/fisiologia , Complexo de Proteína do Fotossistema II/fisiologia , Núcleo Celular/genética , Núcleo Celular/fisiologia , Cloroplastos/genética , Diurona/toxicidade , Espectroscopia de Ressonância de Spin Eletrônica , Mutação , Paraquat/toxicidade , Pisum sativum/genética , Pisum sativum/fisiologia , Fotossíntese/genética , Complexo de Proteínas do Centro de Reação Fotossintética , Complexo de Proteína do Fotossistema I/genética , Complexo de Proteína do Fotossistema II/genética , Folhas de Planta/genética , Folhas de Planta/fisiologiaRESUMO
97 lethal and semilethal mutations were induced by ethyl methanesulfonate, nitrosomethyl urea and gamma-irradiation in the 2D3-F5 region of the X-chromosome of D. melanogaster. Approximately 1 per cent of the tested X-chromosomes carried a lethal in the 2D3-2F5 region. The mutation frequencies per band or DNA content in the region and the whole X-chromosome are equal. Complementation analysis revealed at least 10 functionally independent essential loci in this region including about 10 bands. The data presented in this study support the one band--one gene hypothesis. The Pgd locus coding for 6-phosphogluconate dehydrogenase (6PGD) is mapped in the 2D3 (OR 2D4) band. Isolation of 11 lethal or semilethal point mutations with null or reduced 6PGD activity shows that the Pgd locus is a vital one.
