Departamento de Biotecnología, Universidad Autónoma Metropolitana Iztapalapa, Mexico, DF, Mexico.
Pest Manag Sci. 2014 Apr;70(4):661-6. doi: 10.1002/ps.3605. Epub 2013 Aug 9.
In addition to high production levels of conidia, the success of entomopathogenic fungi as biological control agents depends both on their prevalence under the environmental conditions found in open fields (resistance to stress) and on the capacity of these conidia to infect pests. This study compares conidium production, infectivity and resistance to thermal and osmotic stress in two strains of Isaria fumosorosea (ARSEF 3302 and CNRCB1) grown either under a normal atmosphere (21% O2) or using enriched oxygen pulses (26% O2).
After 180 h, the ARSEF 3302 strain with 26% O2 pulses increased conidium production nearly fivefold compared with the normal atmosphere, while conidium production by the CNRCB1 strain decreased by 50% under O2 pulses, relative to the values measured with the normal atmosphere. The conidia obtained with 26% O2 pulses had a greater germination rate and resistance to thermal and osmotic stress, in addition to improved infectivity against Galleria mellonella (Lepidoptera) larvae. These findings were associated with an increase in catalase activities for both strains.
An enriched oxygen atmosphere increases the quality of conidia of both strains of I. fumosorosea, with a variable effect on conidium production.
除了高浓度的分生孢子产量外，昆虫病原真菌作为生物防治剂的成功还取决于其在田间环境条件下的流行程度（对胁迫的抗性），以及这些分生孢子感染害虫的能力。本研究比较了在正常大气（21% O2）或富氧脉冲（26% O2）下生长的两株绿僵菌（ARSEF 3302 和 CNRCB1）的分生孢子产量、感染力和对热及渗透胁迫的抗性。
在 180 小时后，与正常大气相比，26% O2 脉冲下的 ARSEF 3302 菌株的分生孢子产量增加了近五倍，而 CNRCB1 菌株的分生孢子产量在 O2 脉冲下减少了 50%，与正常大气下的测量值相比。与正常大气相比，用 26% O2 脉冲获得的分生孢子具有更高的发芽率和对热及渗透胁迫的抗性，以及对家蚕幼虫（鳞翅目）更好的感染力。这些发现与两种菌株的过氧化氢酶活性增加有关。
富氧气氛提高了两株绿僵菌的分生孢子质量，对分生孢子产量有不同的影响。
