生防细菌T132的鉴定及其对采后柑橘炭疽病的抑制效果

【目的】柑橘(Citri)是世界上重要的果树。由胶孢炭疽菌Colletotrichum gloeosporioides(Penz.)]引起的柑橘炭疽病是柑橘生产的主要病害之一。为探索对采后柑橘炭疽病有效的生防措施,分离鉴定柑橘根围土壤中一株细菌T132,并研究其特性及生防效果。【方法】根据菌株T132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8次在人工培养基上传代培养,测定该菌株的遗传稳定性;采用柑橘果实刺伤挑战接种和拮抗菌液直接浸泡健康果实两种方法研究该菌株对柑橘炭疽病的抑菌防病效果;利用洋葱伯克霍尔德氏菌致病因子的特异性引物检测菌株T132是否为潜在的人类致病菌。【结果】菌株T132鉴定为越南伯克霍尔德氏菌(Burkholderia vietnamiensis)。连续8次在人工培养基上传代培养,菌株T132抑制胶孢炭疽病菌生长的能力没有发生明显改变。菌株T132对胶孢炭疽菌C.gloeosporioides引起的柑橘炭疽病有明显的防治作用,刺伤接种的防效为88.2%,自然发病的防效为54.9%。未检测到该拮抗菌株有人体致病相关的洋葱伯克霍尔德氏菌致病因子(BCESM)毒力基因。【结论】首次报道对柑橘采后炭疽病具有生防效果、对人类相对安全的越南伯克霍尔德氏菌生防菌株。

Characterization of a bacterial strain T132 and its effect on postharvest citrus anthracnose

Objective] Citrus (Citri) is an economically important fruit crop in the world. The anthracnose caused by Colletotrichum gloeosporioides (Penz.) Sacc. is one of the main diseases in citrus production. For exploring of an effective biocontrol measure against citrus postharvest anthracnose, a bacterial biocontrol strain T132 isolated from the rhizosphere soil of citrus was identified and characterized. The efficacy of the biocontrol strain against citrus postharvest anthracnose disease was evaluated. Methods] Identification of strain T132 was carried out by using 16S rDNA sequence homology comparison as well as morphological, physiological and biochemical characteristics. The antagonistic stability of the strain T132 was determined by continuously transferring it on artificial media for 8 generations. The efficacy of strain T132 in controlling citrus postharvest anthracnose was performed by stab inoculation and naturally infected methods. The use of specific primers detect the strain T132 of the pathogenic factor of Burkholderia cepacia as a potential human pathogens. Results] Strain T132 was identified as Burkholderia vietnamiensis based on its morphological traits, phyiological and biochemical characters as well as 16S rDNA sequence analysis. Less change in the suppressive ability of antagonizing against growth of C. gloeosporioides was observed during 8 generations of transfers on artificial media. The strain T132 had significant efficacy in controlling citrus anthracnose disease causing by C. gloeosporioides. The average efficacies of the strain T132 in controlling the disease were 88.2% in artificial inoculation test and 54.9% in natural infection test 20 d and 60 d after of the antangonist applications, respectively. It was no virulence gene of Burkholderia cepacia epidemic strain marker (BCESM) existed. Conclusion] This is the first report of B. vietnamiensis as a biocontrol agent against citrus postharvest anthracnose disease and the relative safety of biocontrol strains on human.