芽孢杆菌FJAT-55034的鉴定、生长特性及对梨轮纹病菌的抑菌活性

Bacillus sp. FJAT-55034: identification, growth characteristics, and antagonistic effect on Botryosphaeria dothidea causing pear ring rot

摘要:

【背景】由葡萄座腔菌(Botryosphaeria dothidea)引起的梨轮纹病是梨栽培生产中的主要病害之一，造成巨大的经济损失。【目的】对梨轮纹病菌具有较高拮抗活性的菌株FJAT-55034进行鉴定、生长特性及抑菌活性评价，为梨轮纹病的生物防治提供菌种资源。【方法】采用形态学观察、生理生化测定和16S rRNA基因序列分析进行拮抗菌株FJAT-55034的鉴定；通过生长曲线、培养温度和pH测定，研究该菌株的生长特性。采用抑菌圈法测定该菌株的抑菌谱；采用共培养、显微镜观察和果实回接，测定菌株FJAT-55034对梨轮纹病菌生长的抑制作用。【结果】拮抗菌株FJAT-55034鉴定为贝莱斯芽孢杆菌(Bacillus velezensis)。该菌株在20-50 ℃ (最适温度30 ℃)和pH 5.0-9.0 (最适pH值7.0)均能够生长，NaCl添加量为0-5%时，该菌株均能够较好地生长。菌株FJAT-55034对6种果树不同病原真菌均具有不同程度的抑制作用，抑菌圈直径范围为19.8-29.1 mm；与梨轮纹病菌共培养后，菌株FJAT-55034对菌丝生长的抑制率为77.2%。菌株FJAT-55034能够有效地抑制梨轮纹病斑的扩展，处理梨果实5 d后对梨轮纹病的抑制率为66.0%。【结论】菌株FJAT-55034对梨轮纹病菌有较好的抑制效果，可作为梨轮纹病的生防备选菌株。

关键词:贝莱斯芽孢杆菌;轮纹病菌;生物学特性;拮抗菌;梨

Abstract:

[Background] Pear ring rot caused by Botryosphaeria dothidea is one of the major diseases in pear cultivation, causing huge economic losses. [Objective] To identify the strain FJAT-55034 with high antagonistic activity against B. dothidea and evaluate its growth characteristics and antifungal activity, so as to provide an alternative strain for the biocontrol of pear ring rot. [Methods] Morphological characteristics, physiological and biochemical properties, and 16S rRNA gene sequencing were employed to identify the antagonistic strain FJAT-55034. Furthermore, we studied the growth characteristics of the strain by establishing the growth curve and determining the culture temperature and pH. The inhibition zone method was employed to determine the inhibitory spectrum of this strain. Finally, co-culture, microscopic observation, and pathogen inoculation in fruits were conducted to evaluate the antagonistic effect of strain FJAT-55034 on B. dothidea. [Results] The antagonistic strain FJAT-55034 was identified as Bacillus velezensis. It can survive at 20–50 ℃ (optimum 30 ℃) and pH 5.0–9.0 (optimum pH 7.0) and grow well with 0–5% NaCl. The strain exerted inhibitory effects on 6 pathogenic fungal species derived from fruit trees, with the inhibition zone diameters ranging from 19.8 mm to 29.1 mm. The inhibition rate of FJAT-55034 on the mycelial growth of B. dothidea was 77.2%. Moreover, the strain inhibited the expansion of pear ring rot with an inhibition rate of 66.0%. [Conclusion] The strain FJAT-55034 presented a desirable inhibitory effect on B. dothidea and served as an alternative strain for the biocontrol of pear ring rot.

Key words:Bacillus velezensis;Botryosphaeria dothidea;biological characteristics;antagonistic bacteria;pear