Streptomyces hygroscopicus subsp. hygroscopicus 5-4: A Potential Biocontrol Agent for Fusarium Wilt of Banana

Fusarium wilt of banana caused by Fusarium oxysporum f. sp. cubense tropical race 4 (Foc TR4) is one of the most disastrous fungal diseases. Biological control is a promising strategy for controlling Fusarium wilt of banana. To explore endophytic actinomycetes as biocontrol resources against Foc TR4, antagonistic strains were isolated from different tissues of medicinal plants. Here, a total of 144 actinomycetes were isolated and belonged to Nonomuraea, Kitasatospora, and Streptomyces. Forty-three isolates exhibited antifungal activities against Foc TR4. The strain labeled with 5-4 isolated from roots of Piper austrosinense had a broad-spectrum antifungal activity by the production of chitinase and β-1,3-glucanase and was identified as Streptomyces hygroscopicus subsp. hygroscopicus 5-4. Furthermore, disease index of banana wilt was significantly reduced by application of strain 5-4 in comparison with application of Foc TR4 alone. Exogenous application of strain 5-4 increased the expression levels of defense genes such as (PAL), peroxidase (POD), pathogenesis-related protein 1 (PR-1), hydrolytic enzymes (β-1,3-glucanase), lysin motif receptor kinase 1 (LYK-1), and mitogen-activated protein kinase 1 (MPK-1). The antifungal mechanism assay demonstrated that extracts of strain 5-4 inhibited spore gemination and hyphal growth of Foc TR4, and caused abnormally swollen, deformity, and rupture of Foc TR4 hypha. Thus, S. hygroscopicus subsp. hygroscopicus 5-4 could be used as a potential biological agent for controlling Fusarium wilt of banana.

回答1.Streptomyces hygrocompus subsp. hygroscopicus 5-4具有哪些作用；2.文中有哪些基因内容：

回答：

1. Streptomyces hygroscopicus subsp. hygroscopicus 5-4具有广谱的抗真菌活性，能够通过产生壳聚糖酶和β-1,3-葡聚糖酶来抑制Foc TR4的生长。它可以作为一种潜在的生物制剂来控制香蕉枯萎病。此外，它还可以增强植物的防御能力，并抑制Foc TR4的孢子萌发和菌丝生长。
2. 文中提到的基因有：苯丙氨酸解氨酶（PAL）、过氧化物酶（POD）、病原相关蛋白1（PR-1）、β-1,3-葡聚糖酶、溶菌酶结构域受体激酶1（LYK-1）和丝裂原活化蛋白激酶1（MPK-1）。