Abstract:

In this study, 20 saline\|alkali tolerant Trichoderma strains were isolated and screened from 48 saline\|alkali soil samples collected in Tianjin, Hebei Province by dilution plate coating method. When they were cultured on PDA medium at 8% NaCl concentration and pH 8.0 for 7 days, colony diameter went up to 1.0~5.9 cm. Phytophthora nicotianae ACCC38065 was used as pathogen to evaluate the disease\|resistant effect of Trichoderma selected. Six strains were selected, which have better antagonistic effect on Phytophthora nicotianae ACCC38065. Of which, strain 28TJ19 has the best antagonism effect. Tablet confrontation and inhibition rate were 52.8% and 71.6%, respectively, followed by strain 28HB14(41.7%, 76.2%)、29HB16(41.7%, 67.3%). These six strains were classified and identified by morphological observation, ITS sequence analysis and TEF sequence analysis. Four of them were identified as Trichoderma harzianum. The other two strains were Trichoderma longibrachiatum. The results of greenhouse test indicated that all these 6 strains had bio\|control effect of different degrees on tobacco blank shank. Among them the effect of strain 29TJ04 and 29HB16 were the best, which could reach 100%.

Key words: saline\, alkali tolerance, tobacco black shank resistance, Trichoderma, screening and identification

摘要：

采用稀释平板涂布法，从天津、河北地区采集的48份盐碱土中分离筛选得到20株耐盐碱木霉菌株，在含8% NaCl，pH 8.0的PDA培养基中培养7 d，菌落直径达1.0~5.9 cm。通过平板对峙培养和发酵液活性测定得到6株对Phytophthora nicotianae ACCC38065具有较好拮抗作用的菌株。其中，菌株28TJ19对Phytophthora nicotianae ACCC38065的拮抗效果最好，平板对峙和发酵液抑制率分别为52.8%、71.6%，其次为菌株28HB14(41.7%, 76.2%)、29HB16(41.7%, 67.3%)。利用形态学观察、ITS序列分析以及TEF序列分析对这6株菌株进行分类鉴定，4株菌株鉴定为哈茨木霉(Trichoderma harzianum)，另外2株为长枝木霉(Trichoderma longibrachiatum)。经盆栽试验发现，这6株菌对烟草黑胫病均具有不同程度的防治效果，菌株29TJ04、29HB16的防效最好，达100%。

关键词: 耐盐碱；抗烟草黑胫病；木霉菌；筛选鉴定