木霉与被孢霉合成菌群对三七的促生防病效果

Growth-promoting and disease-control effects of Trichoderma and Mortierella synthetic microbial communities on Panax notoginseng (Burk.) F. H. Chen

  • 摘要: 【目的】 比较不同浓度和比例混合的木霉与被孢霉合成菌群对三七连作障碍的缓解效果,筛选能显著促进三七生长和增强其抗病性的合成菌群,为开发安全高效的三七根腐病防治菌剂提供理论参考。【方法】 采用平板对峙法从7株木霉菌(50FZ1、Z2-2-2、3NG-1、2ZG-3、200FN6、2ZG和500FZ1)和4株被孢霉菌(B27、B28、B28-1和NB28)中筛选出既无相互抑制作用又能明显拮抗三七根腐病菌的菌株;对筛选出的木霉菌和被孢霉菌设置单菌株及二者按不同浓度和比例混合的合成菌群处理,以等体积无菌水为对照组(CK),比较测定合成菌群及相应单菌株对缓解三七连作障碍的影响,以及合成菌群和相应单菌株对三七的诱导抗病性。【结果】 平板对峙试验结果显示,木霉菌菌株3NG-1与被孢霉菌菌株B28-1的相容性良好,且2株菌对4株三七根腐病菌(RS6、M、F3和Z5)的拮抗作用最强,其中菌株3NG-1对4株三七根腐病菌的抑制率均在75.00%以上。菌株3NG-1与B28-1组成的合成菌群施用于连作三七盆栽后,不同浓度和比例混合的合成菌群促生及抗病效果存在差异,与CK相比,6MT41(孢子悬浮液浓度为1.0×106个/mL时,按40 mL B28-1+10 mL 3NG-1混合)、7MT41(孢子悬浮液浓度为1.0×107个/mL时,按40 mL B28-1+10 mL 3NG-1混合)和7MT14(孢子悬浮液浓度为1.0×107个/mL时,按10 mL B28-1+40 mL 3NG-1混合)处理可显著提高三七存苗率(P<0.05,下同)、显著降低根腐病发病率,联合增效作用明显,尤其是7MT41处理后三七根腐病发病率降至42.50%,并能明显促进三七株高和干重增长。不同浓度和配比的合成菌群对三七皂苷含量的影响存在差异,与CK相比,6MT11(孢子悬浮液浓度为1.0×106个/mL时,按25 mL B28-1+25 mL 3NG-1混合)、7MT11(孢子悬浮液浓度为1.0×107个/mL时,按25 mL B28-1+25 mL 3NG-1混合)和7MT14处理能显著增加三七5种皂苷(R1、Rg1、Re、Rb1和Rd)总含量,效果均优于相应的单菌株处理,尤其是7MT14处理的总皂苷含量最高,为2.84%,是CK的1.47倍。此外,6MT14(孢子悬浮液浓度为1.0×106个/mL时,按10 mL B28-1+40 mL 3NG-1混合)、7MT41和7MT14处理能诱导三七抵御叶部黑斑病菌SL17的侵染,且7MT14处理还能显著增强三七叶片中过氧化氢酶(CAT)、苯丙氨酸解氨酶(PAL)、过氧化物酶(POD)和超氧化物歧化酶(SOD)4种防御酶活性。【结论】 合成菌群7MT14能显著促进三七生长,降低根腐病发病率,增强抗病性,提升三七品质,是一种安全高效的生防合成菌群,具有开发成复合菌剂的潜力。

     

    Abstract: 【Objective】 To compare the effects of synthetic microbial communities composed of Trichoderma and Mortierella mixing with different concentrations and ratios on alleviating continuous cropping obstacles of Panax notoginseng (Burk.) F. H. Chen, and to screen synthetic microbial communities that could significantly promote the growth and strengthen the disease resistance of Panax notoginseng (Burk.) F. H. Chen, which could provide theoretical basis for developing safe and efficient biocontrol agents for Panax notoginseng (Burk.) F. H. Chen root rot. 【Method】 The plate confrontation assay was utilized to screen compatible strains from seven Trichoderma strains (50FZ1, Z2-2-2, 3NG-1, 2ZG-3, 200FN6, 2ZG, and 500FZ1) and four Mortierella strains (B27, B28, B28-1, and NB28) that exhibited no mutual inhibitory but strong antagonism effects against Panax notoginseng (Burk.) F. H. Chen root rot pathogens. The selected Trichoderma and Mortierella strains were treated with single strain and synthetic microbial communities mixed at different concentrations and ratios of the two. Sterile water of the same volume was used as the control (CK). The effects of the synthetic microbial communities and the corresponding single strains on alleviating the continuous cropping obstacles of Panax notoginseng (Burk.) F. H. Chen and the induced disease resistance of Panax notoginseng (Burk.) F. H. Chen by the synthetic microbial communities and the corresponding single strains were compared and determined. 【Result】 The plate confrontation assay revealed that Trichoderma 3NG-1 and Mortierella B28-1 exhibited good compati-bility and the strongest antagonistic effect against four root rot pathogens (RS6, M, F3, and Z5), with Trichoderma 3NG-1 showing inhibition rates exceeding 75.00%. After the synthetic microbial communities composed of strains 3NG-1 and B28-1 was applied to the potted continuously cropped Panax notoginseng (Burk.) F. H. Chen, the synthetic microbial communities with varying concentrations and ratios exhibited varying growth-promoting and disease-resist effects. Compared with CK, synthetic communities 6MT41 (mixing at 40 mL B28-1 + 10 mL 3NG-1 when spore suspension concentration was 1.0×106 spore/mL), 7MT41 (mixing at 40 mL B28-1 + 10 mL 3NG-1 when spore suspension concentration was 1.0×107 spore/mL), and 7MT14 (mixing at 10 mL B28-1 + 40 mL 3NG-1 when spore suspension concentration was 1.0×107 spore/mL) significantly increased the survival rate of Panax notoginseng (Burk.) F. H. Chen (P<0.05, the same below) and reduced the incidence of root rot, with a notable synergistic effect. In particular, the 7MT41 treatment reduced the incidence of root rot to 42.50%, and 7MT14 treatment also greatly promoted the growth in height and dry weight of Panax notoginseng (Burk.) F. H. Chen. The synthetic microbial communities with varying concentrations and ratios had different effects on saponin content. Compared with CK, 6MT11 (mixing at 25 mL B28-1 + 25 mL 3NG-1 when spore suspension concentration was 1.0×106 spore/mL), 7MT11 (mixing at 25 mL B28-1 + 25 mL 3NG-1 when spore suspension concentration was 1.0×107 spore/mL), and 7MT14 significantly increased the total content of five saponins (R1, Rg1, Re, Rb1, and Rd) in Panax notoginseng (Burk.) F. H. Chen, with better results than single strain treatments. Notably, the total saponin content in the 7MT14 treatment reached the highest (2.84%), which was as 1.47 times as that of CK. Additionally, the treatments 6MT14 (mixing at 10 mL B28-1 + 40 mL 3NG-1 when spore suspension concentration was 1.0×106 spore/mL), 7MT41, and 7MT14 could induce Panax notoginseng (Burk.) F. H. Chen to resist subsequent infection by the leaf spot pathogen SL17, and the 7MT14 treatment significantly enhanced the activity of four defense enzymes, namely catalase (CAT), phenylalanine ammonia-lyase (PAL), peroxidase (POD), and superoxide dismutase (SOD),in Panax notoginseng (Burk.) F. H. Chen leaves. 【Conclusion】 Synthetic microbial community 7MT14 significantly promotes the growth of Panax notoginseng (Burk.) F. H. Chen, reduces root rot incidence, enhances systemic resistance, and improves quality, demonstrating its potential as a safe and highly effective biocontrol synthetic microbial community, and be developed into compound agent.

     

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