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您的检索式：作者名="Arne Tronsmo"
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| 1 | Nutrient activation of Trichoderma fungal spores for improved biocontrol activity显示文摘The effect of preliminary nutrient activation on the ability of conidia of the antagonist Trichoderma harzianum P1 (ThP1) to suppress Botrytis cinerea was investigated in laboratory, greenhouse and field trials. Preliminary nutrient activation at 21 ℃ accelerated subsequent germination of the antagonist at temperatures from 9 ℃ to 21 ℃; at ≥ 18 ℃ the germination time of preactivated ThP1 conidia did not differ significantly from that of B. cinerea. When coinoculated with B. cinerea, concentrated inocula of preactivated but ungerminated ThP1 conidia reduced in vitro germination of the pathogen by ≥ 87% at 12 ℃ to 25 ℃; initially-quiescent conidia achieved this level of suppression only at 25 ℃. Application of quiescent ThP1 conidia to detached strawberry flowers in moist chambers reduced infection by B. cinerea by ≥85% at 24 ℃, but only by 35% at 12 ℃. Preactivated conidia reduced infection by ≥60% at 12 ℃. Both quiescent and preactivated conidia significantly reduced latent infection in greenhouse-grown strawberries at a mean temperture of 19 ℃, while only preactivated conidia were effective in the field at a mean temperature of 14 ℃ on the day of treatment application. Trichoderma biocontrol isolates are most effective as highly concentrated inocula. Their antagonism to other fungi may be a result of pregermination respiration. In a nutrient-rich medium, almost all Trichoderma. atroviride P1 (P1) conidia initiated germination processes and increased respiration, even in dense suspensions. When 1×107 P1 conidia per mL were coinoculated with 1×105 B. cinerea conidia per mL, dissolved oxygen fell to <1% within 2 h and the pathogen failed to germinate. More dilute P1 suspensions consumed oxygen slowly enough to allow coinoculated B. cinerea to germinate. On nutrient-poor media, fewer P1 conidia initiated germination. Oxygen consumption by the inoculum and inhibition of B. cinerea were enhanced when P1 conidia were nutrient-activated before inoculation. Pregermination respiration also affected the competitive capacity of the antagonist on solid substrates, where respiratory CO 2 stimulated germination rate and initial colony growth. These parameters were directly correlated with inoculum concentration (R2≥ 0.97, P<0.01). After initiating germination, Trichoderma conidia became more sensitive to desiccation and were killed by drying after only two hours incubation on a nutrient-rich substrate at 23 ℃. Consideration of these effects of germination initiation on the competitive potential of Trichoderma in biological control will bee discussed. | Linda Gordon Hjeljord Arne Tronsmo | 2004 | 浙江大学学报(农业与生命科学版)2004，30，4： | 0 |
| 2 | Quantification of the expression of chitinolytic enzyme encoding genes ech30, ech42 and nag1 in Trichoderma atroviride P1 under varying growth conditions using a real-time RT-PCR assay显示文摘The quantitative expression and the regulation of chitinase-encoding genes ech30, ech42 and nag1 in Trichoderma atroviride P1 under varying growth conditions were investigated using real-time RT-PCR, principle component and multivariate analyses. Twelve media combinations including 0.1% and 3% glucose as carbon source and no (0 mmol/L), low (10 mmol/L) and high (100 mmol/L) ammonium acetate as nitrogen source combined with or without colloidal chitin at 3 time intervals and 2 replications were applied to current study. The real-time RT-PCR analysis showed that the expression of ech30, ech42 and nag1 was regulated by the interaction of nitrogen, glucose and chitin under different growth conditions. The highest and earliest expressions of ech30 were induced by glucose and nitrogen starvation i.e. 0.1% glucose and 10 mmol/L ammonium acetate in the growth media. This was also the case for ech42 and nag1 but at a relatively low level. In contrast, high (3%) glucose and high (100 mmol/L) ammonium acetate concentrations repressed the expression of all the genes studied. These results were confirmed by principle component and multivariate analyses. The effect of chitin on ech30, ech42 and nag1 expression varied depending on the concentrations of glucose and ammonium acetate. | Jihong Liu Clarke Arne Tronsmo Nicholas Clarkel Sonja Sletner Klemsdal | 2004 | 浙江大学学报(农业与生命科学版)2004，30，4： | 0 |
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