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大豆拟茎点茎枯病生防真菌的筛选与鉴定

Screening and Identification of Biocontrol Fungi against Soybean Diaporthe Stem Blight

  • 摘要: 基于从健康大豆中分离到的158株内生真菌,运用平板对峙法、黄化苗接种法和盆栽防效试验等方法筛选大豆拟茎点茎枯病病原物Diaporthe longicolla的拮抗菌。结果表明:7株内生真菌不仅可在平板上抑制D. longicolla菌丝生长,还可抑制其侵染大豆,其中6株初步鉴定为镰孢菌。盆栽防效试验证实抑制活性最明显的2株镰孢菌(SR62和SR115)能显著提高被D. longicolla侵染的大豆出芽率、鲜重和株高,但不能直接促进大豆植株生长。通过形态学和系统发育分析对SR62和SR115进行分类鉴定,发现其均与Fusarium falciforme聚为一支,属于茄腐镰孢菌复合群的第3分支。相较于SR62和SR115,6株强致病力病原镰孢菌对D. longicolla的菌丝生长无显著影响。综上,本研究筛选获得2株茄腐镰孢菌SR62、SR115,该菌株对D. longicolla具有较强拮抗作用,可用于大豆拟茎点茎枯病的防控。

     

    Abstract: Strains with antagonistic effect against Diaporthe longicolla which causes soybean Diaporthe stem blight were screened by plate confrontation method, etiolated hypocotyl inoculation and pot experiment from 158 endophytic fungi isolated from healthy soybean. The results showed that 7 strains which could inhibit the mycelia growth of D. longicolla on PDA and the infection of D. longicolla to soybean were identified, among which six strains were preliminarily identified as Fusarium species. Furthermore, the pot experiment verified that the strains SR62 and SR115 with stronger antagonistic effect could significantly improve the germination rate, fresh weight and plant height of soybean treated with D. longicolla, but could not directly promote the growth of soybean plants. SR62 and SR115 were identified based on morphological and phylogenetic analysis, which were clustered in a clade together with F. falciforme strain NRRL32721 and classified as F. solani species complex(FSSC) clade 3. Compared with SR62 and SR115, the six highly pathogenic Fusarium strains had no significant effect on the mycelial growth of D. longicolla. In conclusion, SR62 and SR115 with strong antagonistic effects were screened, which could be used to control soybean Diaporthe stem blight.