College of Horticulture, Hunan Agricultural University, Changsha, China.
College of Food Science and Technology, Hunan Agricultural University, Changsha, China.
J Food Biochem. 2021 Jan;45(1):e13551. doi: 10.1111/jfbc.13551. Epub 2020 Nov 5.
This study reports the optimization of culture conditions and medium components of M9, an endophytic strain of Bacillus amyloliquefaciens, which we had previously isolated from kiwifruit, and evaluation of its effect on kiwifruit postharvest protection against soft rot. The method of one-factor-at-a-time was used to determine the optimum culture conditions, and response surface methodology was applied to optimize the medium constituents. After optimization, a high rate of antifungal activity (73.12% decrease in decay rate) by M9 culture filtrate against the soft rot fungal pathogen, Botryosphaeria dothidea, was obtained. Compared with the initial culture conditions, the antifungal activity of M9 culture filtrate was increased by 19.5%. Furthermore, a postharvest storage experiment on kiwifruit showed that M9 culture filtrate could maintain the quality of stored kiwifruit, delay fruit senescence, and significantly enhance the storability of kiwifruit. Using liquid chromatography-mass spectrometry, we found that the antifungal activity of M9 was associated with the presence of the C12-surfactin A lipopeptide. PRACTICAL APPLICATIONS: Soft rot caused by Botryosphaeria dothidea is one of the most important diseases of kiwifruit, causing postharvest fruit rot. The disease progresses rapidly and is difficult to control, posing a great threat to the kiwifruit industry. In this study, the culture conditions and medium composition for culture of the strain M9 (kiwifruit endophytic Bacillus amyloliquefaciens) were optimized to maximize the inhibition of B. dothidea. A postharvest storage experiment showed that M9 culture filtrate could improve the disease resistance of kiwifruits, delay the senescence of the fruits, and maintain the quality of kiwifruit during storage. Because M9 is a natural endophyte of kiwifruit, the strategy used in this study was both effective and safe. This work will contribute to the exploitation of B. amyloliquefaciens in controlling the pathogens of kiwifruit and the development of safer and more advanced strategies for the postharvest protection of kiwifruits.
本研究报告了我们先前从猕猴桃中分离出的内生解淀粉芽孢杆菌（Bacillus amyloliquefaciens）菌株 M9 的培养条件和培养基成分的优化，并评估了其对猕猴桃采后软腐病防治的效果。采用单因素法确定最佳培养条件，并用响应面法优化培养基成分。优化后，M9 培养液滤液对软腐病病原菌胶孢炭疽菌（Botryosphaeria dothidea）的抑菌活性（腐烂率降低 73.12%）较高。与初始培养条件相比，M9 培养液滤液的抑菌活性提高了 19.5%。此外，猕猴桃采后贮藏试验表明，M9 培养液滤液能保持贮藏猕猴桃的品质，延缓果实衰老，显著提高猕猴桃的贮藏性。利用液相色谱-质谱联用技术，我们发现 M9 的抑菌活性与 C12-表面活性素 A 脂肽的存在有关。
胶孢炭疽菌引起的软腐病是猕猴桃最重要的病害之一，导致采后果实腐烂。该病害发展迅速，难以控制，对猕猴桃产业构成巨大威胁。本研究优化了菌株 M9（猕猴桃内生解淀粉芽孢杆菌）的培养条件和培养基组成，以最大限度地抑制 B. dothidea。采后贮藏试验表明，M9 培养液滤液能提高猕猴桃的抗病性，延缓果实衰老，保持果实贮藏期的品质。由于 M9 是猕猴桃的天然内生菌，本研究采用的策略既有效又安全。这项工作将有助于利用解淀粉芽孢杆菌控制猕猴桃病原菌，并开发更安全、更先进的猕猴桃采后保护策略。
