RESUMO
BACKGROUND: Feral radish (Raphanus sativus L.) is a problematic weed that has become resistant to acetohydroxyacid synthase (AHAS) inhibitor herbicides due to the Trp574Leu mutation. An AHAS gene mutation that causes herbicide resistance may have negative pleiotropic effects on plant fitness. This study reports the effects of the Trp574Leu mutation on AHAS activity and reproductive traits of R. sativus. RESULTS: Eight of 17 feral radish accessions presented individuals resistant to metsulfuron-methyl at 0.5% to >90.0% and all the resistant individuals analyzed showed the Trp574Leu mutation. Without herbicide selection, the AHAS activity was 3.2-fold higher in the susceptible accession than in the resistant one. The resistant accession was >9000-fold more resistant to metsulfuron-methyl and imazethapyr than the susceptible accession. Under low intraspecific competition during two growing seasons, AHAS-resistant feral radish accessions showed 22-38% and 21-47% lower seed numbers and yield per plant than the susceptible accession. CONCLUSION: This is the first report of fitness cost associated with the AHAS Trp574Leu mutation in R. sativus populations. This fitness cost could reduce frequency of the resistant allele without herbicide selection. © 2018 Society of Chemical Industry.
Assuntos
Acetolactato Sintase/genética , Resistência a Herbicidas/genética , Herbicidas/farmacologia , Proteínas de Plantas/genética , Raphanus/genética , Acetolactato Sintase/metabolismo , Substituição de Aminoácidos , Sulfonatos de Arila/farmacologia , Mutação/genética , Ácidos Nicotínicos/farmacologia , Proteínas de Plantas/metabolismo , Raphanus/efeitos dos fármacos , Reprodução/efeitos dos fármacosRESUMO
Glucosinolates (GSLs) are important secondary metabolites in Brassicaceae plants. Previous studies have mainly focused on GSL contents, types, and biosynthesis-related genes, but the molecular characterization patterns of GSL biosynthesis-related transcription factors remain largely unexplored in radish (Raphanus sativus L.). To isolate transcription factor genes regulating the GSL biosynthesis, genomic DNA and cDNA sequences of RsMYB28 and RsMYB29 genes were isolated in radish. Two R2R3-MYB domains were identified in the deduced amino acid sequences. Subcellular localization and yeast-one hybrid assays indicated that both the RsMYB28 and RsMYB29 genes were located in the nucleus and possessed transactivation activity. Reverse transcription quantitative analysis showed that the RsMYB28 and RsMYB29 genes were expressed in seeds, leaves, stems, and roots at the seedling, taproot thickening, and mature stages. Both genes were highly expressed during the seedling and taproot thickening stages. The expression level of RsMYB28 was found to be up-regulated following wounding, glucose, and abscisic acid treatments, whereas RsMYB29 was up-regulated following wounding and methyl jasmonate treatments. These results provide insights into the biological function and characterization of the RsMYB28 and RsMYB29 genes, and facilitate further dissection of the molecular regulatory mechanism underlying the GSL biosynthesis in radish.
Assuntos
Genes de Plantas , Proteínas de Plantas/genética , Raphanus/genética , Fatores de Transcrição/genética , Sequência de Aminoácidos , Sequência de Bases , Clonagem Molecular , Regulação da Expressão Gênica no Desenvolvimento , Regulação da Expressão Gênica de Plantas , Glucosinolatos/metabolismo , Cebolas/citologia , Peptídeos/química , Filogenia , Epiderme Vegetal/citologia , Proteínas de Plantas/metabolismo , Frações Subcelulares/metabolismo , Fatores de Transcrição/metabolismo , Ativação Transcricional/genéticaRESUMO
BACKGROUND: Soon after the commercial release of sunflower cultivars resistant to imidazolinone herbicides, several uncontrolled feral radish (Raphanus sativus L.) populations were found in south-eastern Buenos Aires, Argentina. These populations were studied in field, glasshouse and laboratory experiments aiming to characterise their resistance profile and to develop management tools. RESULTS: Three feral radish accessions were highly resistant to ten active ingredients of five families of acetohydroxyacid synthase (AHAS)-inhibiting herbicides. Sequence analysis of the AHAS gene detected a Trp574Leu mutation in all resistant accessions. One accession with an intermediate level of resistance was heterozygous for this mutation, probably owing to gene exchange with a susceptible subpopulation located in the field margin. Herbicide-resistant and herbicide-susceptible radish could be controlled in sunflower by alternative herbicides. CONCLUSION: This is the first report of feral radish with resistance to herbicides belonging to all the AHAS-inhibiting herbicide families, conferred by Trp574Leu mutation in the AHAS gene. An appropriate herbicide rotation with alternative herbicides such as fluorochloridone or aclonifen and an increase in the diversity of cropping systems are important for minimising the prevalence of these biotypes.
Assuntos
Acetolactato Sintase/genética , Helianthus/efeitos dos fármacos , Resistência a Herbicidas/genética , Herbicidas/farmacologia , Raphanus/efeitos dos fármacos , Acetolactato Sintase/antagonistas & inibidores , Argentina , Sequência de Bases , Helianthus/genética , Heterozigoto , Imidazóis/farmacologia , Dados de Sequência Molecular , Mutação de Sentido Incorreto , Proteínas de Plantas/antagonistas & inibidores , Proteínas de Plantas/genética , Raphanus/genética , Análise de Sequência de DNARESUMO
Devido à expansão da cultura do nabo-forrageiro para regiões com temperaturas mais elevadas, torna-se de importância o desenvolvimento de cultivares adaptadas a altas temperaturas. Neste trabalho, o objetivo foi selecionar testes de avaliação da qualidade fisiológica de sementes nabo-forrageiro que estimam caracteres genéticos, visando a selecionar genótipos adaptados a condições de alta temperatura. Para isso, sementes de 100 progênies de meio-irmãos de nabo-forrageiro foram submetidas a teste de germinação e vigor (primeira contagem de germinação, classificação do vigor de plântulas, teste de envelhecimento acelerado, germinação e teste da primeira contagem a altas temperaturas), bem como emergência de plântulas em campo. O teste de primeira contagem, germinação, envelhecimento acelerado, primeira contagem e germinação em alta temperatura (20-35°C) são recomendados para delinear estratégias de seleção de populações de nabo-forrageiro adaptados à germinação e emergência de plântulas em campo, em condições de altas temperaturas.
Due to the expansion of the wild crop to regions with higher temperatures is important to develop cultivars adapted to high heat. The aim was to select tests for evaluating seed physiological quality of wild radish to estimating genetic characters in order to select cultivars adapted to high temperature conditions. Hundred of half-brothers of wild radish were subjected to germination test and vigor (first count of germination, classification of seedling vigor, accelerated aging test, germination and testing of the first count at high temperature as well as seedling emergence in field. The germination test, first count test, accelerated aging and high germination test (20-35°C) can be used for the selection of wild radish crop populations adapted to germination and field emergence under high temperatures.
Assuntos
Germinação , Raphanus/embriologia , Raphanus/genética , Sementes , Temperatura Alta , HereditariedadeRESUMO
Devido à expansão da cultura do nabo-forrageiro para regiões com temperaturas mais elevadas, torna-se de importância o desenvolvimento de cultivares adaptadas a altas temperaturas. Neste trabalho, o objetivo foi selecionar testes de avaliação da qualidade fisiológica de sementes nabo-forrageiro que estimam caracteres genéticos, visando a selecionar genótipos adaptados a condições de alta temperatura. Para isso, sementes de 100 progênies de meio-irmãos de nabo-forrageiro foram submetidas a teste de germinação e vigor (primeira contagem de germinação, classificação do vigor de plântulas, teste de envelhecimento acelerado, germinação e teste da primeira contagem a altas temperaturas), bem como emergência de plântulas em campo. O teste de primeira contagem, germinação, envelhecimento acelerado, primeira contagem e germinação em alta temperatura (20-35°C) são recomendados para delinear estratégias de seleção de populações de nabo-forrageiro adaptados à germinação e emergência de plântulas em campo, em condições de altas temperaturas.(AU)
Due to the expansion of the wild crop to regions with higher temperatures is important to develop cultivars adapted to high heat. The aim was to select tests for evaluating seed physiological quality of wild radish to estimating genetic characters in order to select cultivars adapted to high temperature conditions. Hundred of half-brothers of wild radish were subjected to germination test and vigor (first count of germination, classification of seedling vigor, accelerated aging test, germination and testing of the first count at high temperature as well as seedling emergence in field. The germination test, first count test, accelerated aging and high germination test (20-35°C) can be used for the selection of wild radish crop populations adapted to germination and field emergence under high temperatures.(AU)
Assuntos
Temperatura Alta , Germinação , Sementes , Raphanus/embriologia , Raphanus/genética , HereditariedadeRESUMO
Radish floral bud abortion (FBA) is an adverse biological phenomenon that occurs during reproduction. Although FBA occurs frequently, its mechanism remains unknown. To elucidate the molecular mechanism underlying FBA, we detected gene expression differences between aborted and normal buds of radish using cDNA-amplified fragment length polymorphism (AFLP) and real-time polymerase chain reaction (real-time PCR). A total of 221 differentially expressed transcript-derived fragments (TDFs) were detected by 256 cDNA-AFLP primer combinations, of which 114 were upregulated and 107 were downregulated in the aborted buds. A total of 54 TDFs were cloned and sequenced. A BLAST search revealed that all TDFs have homologous sequences and 29 of these corresponded to known genes, whose functions were mainly related to metabolism, stimulus response, transcriptional regulation, and transportation. Expressions of 6 TDFs with different functions were further analyzed by real-time PCR yielding expression profiling results consistent with the cDNA-AFLP analysis. Our results indicated that radish FBA is related to abnormalities in various physiological and biochemical plant processes.
Assuntos
Flores/fisiologia , Regulação da Expressão Gênica de Plantas , Genes de Plantas , Raphanus/genética , Flores/metabolismo , Perfilação da Expressão Gênica , Raphanus/fisiologia , Transcrição GênicaRESUMO
Flow cytometry (FCM) techniques have enabled characterization of the genome size for various plant species. In order to measure the nuclear genome size of a species, reference standards with well-established DNA content are necessary. However, different 2C-values have been described for the same species used as reference standard. This fact has brought about inaccurate genome measurements, making relevant the establishment of optimal DNA reference standards for plant cytometric analyses. Our work revisited the genome size of Arabidopsis thaliana and other seven plant standards, which were denominated "Dolezel's standard set" and have been widely used in plant DNA measurements. These eight plant standards were reassessed for a comparative measurement of their DNA content values, using each plant species as primary standard in a cascade-like manner, from A. thaliana to Allium cepa. The genome size values obtained here were compared to those reported in the literature by statistical analyses. As a result, Raphanus sativus and Drosophila melanogaster were considered the most inadequate primary standards, whereas A. thaliana, Solanum lycopersicum and Pisum sativum were found to be the most suitable.