Transcriptional coupling of DNA repair in sporulating Bacillus subtilis cells.

In conditions of halted or limited genome replication, like those experienced in sporulating cells of Bacillus subtilis, a more immediate detriment caused by DNA damage is altering the transcriptional programme that drives this developmental process. Here, we report that mfd, which encodes a conserved bacterial protein that mediates transcription-coupled DNA repair (TCR), is expressed together with uvrA in both compartments of B. subtilis sporangia. The function of Mfd was found to be important for processing the genetic damage during B. subtilis sporulation. Disruption of mfd sensitized developing spores to mitomycin-C (M-C) treatment and UV-C irradiation. Interestingly, in non-growing sporulating cells, Mfd played an anti-mutagenic role as its absence promoted UV-induced mutagenesis through a pathway involving YqjH/YqjW-mediated translesion synthesis (TLS). Two observations supported the participation of Mfd-dependent TCR in spore morphogenesis: (i) disruption of mfd notoriously affected the efficiency of B. subtilis sporulation and (ii) in comparison with the wild-type strain, a significant proportion of Mfd-deficient sporangia that survived UV-C treatment developed an asporogenous phenotype. We propose that the Mfd-dependent repair pathway operates during B. subtilis sporulation and that its function is required to eliminate genetic damage from transcriptionally active genes.

Controle alternativo do míldio da videira com extrato aquoso de cinamomo e óleo vegetal / Alternative control of downy mildew with aqueous extracts of chinaberry and vegetable oil

Este trabalho teve como objetivo avaliar o efeito do extrato aquoso de cinamomo (Melia azederach) no controle de Plasmopara viticola. Para o teste de germinação de esporângios do oomiceto foram utilizadas as concentrações de 0, 5, 10, 15, 20 e 25 mL L-1 de extrato aquoso de cinamomo (EC), além dos tratamentos com mancozebe e calda bordalesa. No experimento em casa de vegetação e a campo foram estudadas as concentrações de 0, 30, 40 e 50 mL L-1 de EC (1:10 p/v), além de um tratamento com calda bordalesa (1:1:100). No segundo experimento, em condições de campo, os tratamentos foram: 0, 10, 20, 30, 40 e 50 mL L-1 de EC, acrescidos de óleo vegetal a 2,5 mL L-1, calda bordalesa e testemunha absoluta. No teste de germinação, verificou-se maior inibição de P. viticola às 2 horas após a incubação, para as concentrações de 20 e 25 mL L-1 de EC com uma redução de 66,5 e 62,0%, respectivamente. Em condições de casa de vegetação o EC a 40 e 50 mL L-¹ apresentou reduções de 70,0% e 86,0% da doença, respectivamente. Enquanto que as mesmas concentrações, no primeiro ciclo do experimento a campo, apresentaram um decréscimo de 34,0% e 31,0%, respectivamente. No segundo ciclo, o uso de óleo vegetal como adjuvante mascarou o efeito do EC e a aplicação isolada de óleo vegetal reduziu em 76,3% a área abaixo da curva de progresso da doença (AACPD), similar aos resultados obtidos com todas as concentrações de EC e com a calda bordalesa.

ALTERNATIVE CONTROL OF DOWNY MILDEW WITH AQUEOUS EXTRACTS OF CHINABERRY AND VEGETABLE OIL. The aim of the present study was to evaluate the effect of aqueous extract of chinaberry (Melia azedarach) in the control of Plasmopara viticola. For the germination test of sporangia of the oomycete, concentrations of 0, 5, 10, 15, 20 and 25 mL L-1 of aqueous extract of chinaberry (EC) were used, as well as treatments with mancozeb and bordeaux mixture. The experiment in the greenhouse and field involved concentrations of 0, 30, 40 and 50 mL L-1 of EC (1:10 w/v) and a treatment with bordeaux mixture (1:1:100 ). In the second experiment in the field the treatments were: 0, 10, 20, 30, 40 and 50 mL L-1 of EC with an added 2.5 mL L-1 of vegetable oil, the bordeaux mixture and an absolute control. In the germination test, there was highest inhibition of P. viticola at 2 hours after incubation at 20° C, for the 20 and 25 mL L-1 concentrations of the EC, with a reduction of 66.5 and 62.0%, respectively. In the greenhouse conditions, the EC at a concentration of 40 and 50 mL L-1 showed a reduction of 70.0% and 86.0% of the disease, respectively, while the same concentrations in the first cycle of the field experiment showed a decrease of 34.0% and 31.0%, respectively. However, in the second cycle, the use of vegetable oil as an adjunct masked the effect of the EC, and the isolated application of vegetable oil decreased the area under the disease progress curve (ADPC) by 76.3%, similar to results obtained with all concentrations of EC and with the bordeaux mixture.

Controle alternativo do míldio da videira com extrato aquoso de cinamomo e óleo vegetal / Alternative control of downy mildew with aqueous extracts of chinaberry and vegetable oil

Este trabalho teve como objetivo avaliar o efeito do extrato aquoso de cinamomo (Melia azederach) no controle de Plasmopara viticola. Para o teste de germinação de esporângios do oomiceto foram utilizadas as concentrações de 0, 5, 10, 15, 20 e 25 mL L-1 de extrato aquoso de cinamomo (EC), além dos tratamentos com mancozebe e calda bordalesa. No experimento em casa de vegetação e a campo foram estudadas as concentrações de 0, 30, 40 e 50 mL L-1 de EC (1:10 p/v), além de um tratamento com calda bordalesa (1:1:100). No segundo experimento, em condições de campo, os tratamentos foram: 0, 10, 20, 30, 40 e 50 mL L-1 de EC, acrescidos de óleo vegetal a 2,5 mL L-1, calda bordalesa e testemunha absoluta. No teste de germinação, verificou-se maior inibição de P. viticola às 2 horas após a incubação, para as concentrações de 20 e 25 mL L-1 de EC com uma redução de 66,5 e 62,0%, respectivamente. Em condições de casa de vegetação o EC a 40 e 50 mL L-¹ apresentou reduções de 70,0% e 86,0% da doença, respectivamente. Enquanto que as mesmas concentrações, no primeiro ciclo do experimento a campo, apresentaram um decréscimo de 34,0% e 31,0%, respectivamente. No segundo ciclo, o uso de óleo vegetal como adjuvante mascarou o efeito do EC e a aplicação isolada de óleo vegetal reduziu em 76,3% a área abaixo da curva de progresso da doença (AACPD), similar aos resultados obtidos com todas as concentrações de EC e com a calda bordalesa. (AU)

ALTERNATIVE CONTROL OF DOWNY MILDEW WITH AQUEOUS EXTRACTS OF CHINABERRY AND VEGETABLE OIL. The aim of the present study was to evaluate the effect of aqueous extract of chinaberry (Melia azedarach) in the control of Plasmopara viticola. For the germination test of sporangia of the oomycete, concentrations of 0, 5, 10, 15, 20 and 25 mL L-1 of aqueous extract of chinaberry (EC) were used, as well as treatments with mancozeb and bordeaux mixture. The experiment in the greenhouse and field involved concentrations of 0, 30, 40 and 50 mL L-1 of EC (1:10 w/v) and a treatment with bordeaux mixture (1:1:100 ). In the second experiment in the field the treatments were: 0, 10, 20, 30, 40 and 50 mL L-1 of EC with an added 2.5 mL L-1 of vegetable oil, the bordeaux mixture and an absolute control. In the germination test, there was highest inhibition of P. viticola at 2 hours after incubation at 20° C, for the 20 and 25 mL L-1 concentrations of the EC, with a reduction of 66.5 and 62.0%, respectively. In the greenhouse conditions, the EC at a concentration of 40 and 50 mL L-1 showed a reduction of 70.0% and 86.0% of the disease, respectively, while the same concentrations in the first cycle of the field experiment showed a decrease of 34.0% and 31.0%, respectively. However, in the second cycle, the use of vegetable oil as an adjunct masked the effect of the EC, and the isolated application of vegetable oil decreased the area under the disease progress curve (ADPC) by 76.3%, similar to results obtained with all concentrations of EC and with the bordeaux mixture. (AU)