Exploring Rain as Source of Biological Control Agents for Fire Blight on Apple
Exploring Rain as Source of Biological Control Agents for Fire Blight on Apple
复制标题
DOI：
10.3389/fmicb.2020.00199
复制
发表时间：
2020-02-14
影响因子：
5.2
通讯作者：
Vinatzer, Boris A.
中科院分区：
文献类型：
--
作者：
Llontop, Marco E. Mechan;Hurley, Kelly;Vinatzer, Boris A.
在植物上的存活性差会限制生物防治剂（BCA）在田间的功效。然而，细菌在大气中生存，尽管它们暴露在高太阳辐射和极端温度下。如果大气中的条件与植物表面的环境条件相似或更极端，则降水可以作为强大的BCAs的水库。为了验证这一假设，254个雨传菌株进行了筛选，在体外抑制欧文氏菌，火疫病的病原体，以及其他植物病原细菌，真菌和卵菌。两株分离物对大肠杆菌有较强的抗菌活性。amylovora和其他植物病原细菌，而其他分离物对真菌和卵菌病原体表现出活性。存活试验表明，两株菌株对E.梨食心虫与E.食淀粉的。病原菌种群规模和相关的火疫病症状显着减少时，离体苹果花处理病原菌接种前的两个分离物，但是，在一个果园内附着的花朵上的疾病减少是不一致的。通过全基因组测序，分离物分别被鉴定为成团泛菌和菠萝泛菌。UV诱变筛选指出吩嗪抗生素D-丙氨酰灰甲苯酸合成基因簇是成团假单胞菌分离物的抗微生物活性的基础。我们的工作揭示了沉淀作为一种未被开发的BCAs来源的潜力，全基因组测序作为一种有效的方法来精确地识别BCAs，紫外诱变作为一种技术上简单的筛选来研究BCAs的遗传基础。需要更多的田间试验来确定所鉴定的BCAs在火疫病防治中的功效。
Poor survival on plants can limit the efficacy of Biological Control Agents (BCAs) in the field. Yet bacteria survive in the atmosphere, despite their exposure to high solar radiation and extreme temperatures. If conditions in the atmosphere are similar to, or more extreme than, the environmental conditions on the plant surface, then precipitation may serve as a reservoir of robust BCAs. To test this hypothesis, two hundred and fifty-four rain-borne isolates were screened for in vitro inhibition of Erwinia amylovora, the causal agent of fire blight, as well as of other plant pathogenic bacteria, fungi and oomycetes. Two isolates showed strong activity against E. amylovora and other plant pathogenic bacteria, while other isolates showed activity against fungal and oomycete pathogens. Survival assays suggested that the two isolates that inhibited E. amylovora were able to survive on apple blossoms and branches similarly to E. amylovora. Pathogen population size and associated fire blight symptoms were significantly reduced when detached apple blossoms were treated with the two isolates before pathogen inoculation, however, disease reduction on attached blossoms within an orchard was inconsistent. Using whole genome sequencing, the isolates were identified as Pantoea agglomerans and P. ananatis, respectively. A UV-mutagenesis screen pointed to a phenazine antibiotic D-alanylgriseoluteic acid synthesis gene cluster as being at the base of the antimicrobial activity of the P. agglomerans isolate. Our work reveals the potential of precipitation as an under-explored source of BCAs, whole genome sequencing as an effective approach to precisely identify BCAs, and UV-mutagenesis as a technically simple screen to investigate the genetic basis of BCAs. More field trials are needed to determine the efficacy of the identified BCAs in fire blight control.