生防菌株1404的鉴定及其对采后柑橘炭疽病的防治效果

Characterization of a bacterial biocontrol strain 1404 and its efficacy in controlling postharvest citrus anthracnose

摘要:

摘要：【目的】柑橘是世界上重要的果树。由胶孢炭疽菌[Colletotrichum gloeosporioides (Penz.) Sacc.]引起的柑橘炭疽病是柑橘生产的主要病害。为开发对采后柑橘炭疽病有效的生防措施，对从辣椒根际土壤中分离的一株生防细菌1404进行了鉴定，并对其特性及生防效果进行了研究。【方法】根据菌株1404的形态特征、生理生化特性以及16S rDNA序列对其进行鉴定；通过连续在人工培养基上转代培养，测定该菌株拮抗活性的稳定性；用果实刺伤接种法对采后柑橘炭疽病的防效进行测定。【结果】菌

Abstract:

Abstract: [Objective] Anthracnose caused by Colletotrichum gloeosporioides (Penz.) Sacc. is a main disease in citrus production. To develop an effective biocontrol measure against citrus postharvest anthracnose, we screened antagonistic microbes and obtained a bacterial strain 1404 from the rhizospheric soil of chili plants in Nanning city, Guangxi, China. The objectives of the present study were to: (1) identify and characterize the antagonistic bacterium; (2) to evaluate the efficacy of the antagonistic strain in controlling citrus postharvest anthracnose disease. [Methods] Strain 1404 was identified by comparing its 16S rDNA sequence with related bacteria from GenBank database, as well as analyzing its morphological, physiological and biochemical characters. The antagonistic stability of the strain 1404 was determined by continuously transferring it on artificial media. The effect of the strain on suppressing citrus anthracnose at postharvest stage was tested by stab inoculation method. [Results] The 16S rDNA of strain 1404 was amplified with primers PF1 (5′-AGAGTTTGATCATGGCTCAG-3′) and PR1 (5′-TACGGTTACCTTGTTACGACTT-3′) and its sequence submitted to GenBank (accession number: GU361113). Strain 1404 clustered with the GenBank-derived Brevibacillus brevis strains in the 16S-rDNA-sequence-based phylogenetic tree at 100 % bootstrap level. The morphological traits, physiological and biochemical characters of strain 1404 agreed with that of Brevibacillus brevis. Less change in the suppressive ability of antagonist against growth of Colletotrichum gloeosporioides was observed during four continuous transfers on artificial media. The average control efficacy of the strain was 64.9 % against the disease 20 days after the antagonist application. [Conclusion] Strain 1404 was identified as Brevibacillus brevis based on its morphological traits, phyiological and biochemical characters as well as 16S rDNA sequence analysis. The antagonist was approved to be a promising biocontrol agent. This is the first report of Brevibacillus brevis as an effective antagonist against citrus postharvest anthracnose disease.