Optimising liquid production of the insect pathogenic fungus Metarhizium anisopliae and enhancing the shelf life of blastospores.

金龟子绿僵菌等昆虫病原真菌作为化学农药的环保型替代品受到广泛关注。真菌生物防治剂商业化的主要障碍之一是生产成本。早期的“后续”NERC资助（NE/E522308/1）表明，金龟子分枝杆菌V275、3297和4556菌株高度稳定（在多次体外继代培养中保持其毒力），并在碎米上产生高产量的气生分生孢子。最近，我们发现这些菌株在液体培养基中产生胚孢子。这为在液体介质中进行大规模生产创造了机会，这将进一步降低生产成本，并产生极具竞争力的金属镁基产品。芽孢是薄壁的感染繁殖体，比气生分生孢子更弱，保质期更短（室温下1-3天，而室温下为数月）。通过控制营养物质和培养基水分活性，可以提高真菌繁殖体的产量、毒力和货架期。该项目的目的是开发培养基，以(i)提高绿僵菌芽孢杆菌的产量，（ii）在不损失质量的情况下证明规模化生产，（iii）开发配方以延长芽孢的保质期。总的来说，拟议的工作将降低生产成本，并加快开发基于绿僵菌芽孢杆菌的高竞争力商业产品，用于控制一系列节肢动物害虫（如藤象鼻虫、蓟马、蜱虫）。

There is much interest in the development of insect pathogenic fungi like Metarhizium anisopliae as environmentally friendly alternatives to chemical pesticides. One of the major hurdles in the commercialisation of fungal biological control agents is production cost. An earlier 'Follow-On' NERC grant (NE/E522308/1) showed that M. anisopliae strains V275, 3297 and 4556 are highly stable (retaining their virulence upon repeated in vitro sub-culturing), and produce high yields of aerial conidia on broken rice. Recently, we found that these strains produced blastospores in liquid media. This creates the opportunity for mass production in liquid media which would reduce production costs further and generate highly competitive Metarhizium-based products. Blastospores are thin walled infection propagules which are less robust and have a shorter shelf life than aerial conidia (1-3 days versus several months at room temperature). The yield, virulence and shelf life of fungal propagules can be improved by manipulating nutrients and media water activity. The aims of this project are to develop media to (i) increase yields of M. anisopliae blastospores, (ii) demonstrate upscaled production without loss of quality and (iii) to develop formulations to enhance blastospore shelf life. Overall, the proposed work will reduce production costs and accelerate development of highly competitive commercial products based on M. anisopliae blastospores for control of a range of arthropod pests (e.g. vine weevil, thrips, ticks).