• 关键词：TSNA  根瘤土壤杆菌属  16SrDNA  菌株鉴定

• 基金项目：国家烟草专卖局科技计划资助项目(No.110200202004B)

• 汪安云
• 云南省烟草科学研究所植保室, 玉溪 653100

• 黄琼
• 云南农业大学植病重点实验室, 昆明 650201

• 摘要：从白肋烟TRM品种叶片中分离得到一株能降低白肋烟烟草中特有的亚硝胺(TSNA)含量的内生细菌菌株,该菌株能还原硝酸盐和亚硝酸盐.通过形态、生理生化特性分析以及16SrDNA序列进行同源比较,鉴定该菌株为根瘤土壤杆菌属,定名为Agrobaterium tumefaciens.该菌株最佳生长温度为25～30℃,最佳培养基为TSB,最适pH值为7.0～8.0.在采收前一天,对白肋烟品种TN86进行菌株喷洒处理;检测晾制期间TSNA、硝酸盐、亚硝酸盐含量变化.结果表明,在晾制前期,TSNA含量比较低且变化幅度较小;晾制30d时,TSNA含量达到最大;在晾制末期,喷洒菌株处理的烟叶中TSNA含量有明显的降低,比同一时期对照烟叶中TSNA含量降低了81.3%;常规化学成分及烟叶感官质量与对照相似,都达到了优级白肋烟标准.通过分析该菌株对硝酸盐、亚硝酸盐及TSNA的影响,推测该菌株可能通过还原亚硝酸盐,使亚硝酸盐含量减少,从而降低了TSNA的形成.

• Abstract：A endogenous bacteria strain of reducing TSNA Contents was isolated from the burley TRM.,it could deoxidize NO₃^--N, NO₂^--N.It was identified as Agrobaterium tumefaciens based on morphological, physio-biochemical characteristics and 16s rDNA sequence analysis. Under the optimal growth conditions,with time of temperature of 25℃～30℃,pH of 7.0～8.0, culture medium of TSB.This strain was applied to the burley tobacco TN86 by spraying the leaves of the day before harvested. The contents of NO₃^--N,NO₂^--N. TSNA of leaf samples were detected after leaves air-curing ended. The results showed that endogenous bacteria could reduce the TSNA contents of burley tobacco leaves. The content of TSNA was all very low for the untreated control (CK) and the spraying treatment during the forepart of Air-curing process. Levels of TSNA reached a peak for the spraying treatment and the untreated control after 30 days of curing. At the end of curing, the TSNA for the spraying treatments was decreased greatly. TSNA at the end of curing decreased 81.3%, compared to the control. Other elements (protein, sugar, alkaloids and the sense qulity) were similar in endogenous-treated leaf compared to the untreated control.It was assumed that the strain might reduce TSNA by deoxidizing NO₃^--N, NO₂^--N.

• Key words：endogenous bacteria  TN86  pour roots  spraying the leaves  TSNA

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