目的:在Poöideae亚科(禾本科)中,某些草种具有抗草食动物生物碱,这些生物碱是由属于Epichlooè属(Clavipitaceae)的内生真菌合成的。这些共生内生菌的保护作用可以有所不同,取决于特定植物-内生菌协会和植物部分中的生物碱浓度。
方法:我们进行了文献综述,以确定包含六种重要牧场物种中各种植物部分的生物碱浓度数据的文章:黑麦草,L.Perenne,L.pratense,L.multiflorum|L.刚体,和红羊茅与其常见的内生菌有关。我们考虑了生物碱洛林(1-氨基吡咯烷),过胺(吡咯并吡嗪),麦角缬氨酸(麦角生物碱),和LolitremB(吲哚-二萜),and.尽管所有这些生物碱都显示出对昆虫食草动物的生物活性,麦角缬氨酸和lolitremB对哺乳动物有害。
结果:多年生草L.pratense和L.arundinaceum中的洛林生物碱含量高于一年生植物L.mulflorum和L.gividum,在生殖组织中而不是在植物结构中。这可能是由于多年生物种中更多的生物量积累,可以导致更高的内生菌菌丝体生物量。多年生乳杆菌中的过胺浓度高于高丽生乳杆菌,不受植物部分的影响。这可以归因于过胺的高植物内迁移率。Ergovaline和LolitremB,两种疏水化合物,与通常存在真菌菌丝体的植物部位有关,它们在植物生殖组织中的浓度较高。只有洛林生物碱数据足以进行地下组织分析,并且浓度低于地上部分。
结论:我们的研究提供了跨寄主草和植物部分的真菌生物碱变异的综合,对于理解内生菌赋予的防御程度至关重要。可以通过考虑植物内的内生菌生长和生物碱的迁移率来理解模式。我们的研究发现了研究差距,包括根中生物碱存在的有限文件,以及需要调查不同环境条件的影响。
OBJECTIVE: In the subfamily Poöideae (Poaceae), certain grass species possess anti-herbivore alkaloids synthesized by fungal endophytes that belong to the genus Epichloë (Clavicipitaceae). The protective role of these symbiotic endophytes can vary, depending on alkaloid concentrations within specific plant-endophyte associations and plant parts.
METHODS: We conducted a literature
review to identify articles containing alkaloid concentration data for various plant parts in six important pasture species, Lolium arundinaceum, Lolium perenne, Lolium pratense, Lolium multiflorum|Lolium rigidum and Festuca rubra, associated with their common endophytes. We considered the alkaloids lolines (1-aminopyrrolizidines), peramine (pyrrolopyrazines), ergovaline (ergot alkaloids) and lolitrem B (indole-diterpenes). While all these alkaloids have shown bioactivity against insect herbivores, ergovaline and lolitrem B are harmful for mammals.
RESULTS: Loline alkaloid levels were higher in the perennial grasses L. pratense and L. arundinaceum compared to the annual species L. multiflorum and L. rigidum, and higher in reproductive tissues than in vegetative structures. This is probably due to the greater biomass accumulation in perennial species that can result in higher endophyte mycelial biomass. Peramine concentrations were higher in L. perenne than in L. arundinaceum and not affected by plant part. This can be attributed to the high within-plant mobility of peramine. Ergovaline and lolitrem B, both hydrophobic compounds, were associated with plant parts where fungal mycelium is usually present, and their concentrations were higher in plant reproductive tissues. Only loline alkaloid data were sufficient for below-ground tissue analyses and concentrations were lower than in above-ground parts.
CONCLUSIONS: Our study provides a comprehensive synthesis of fungal alkaloid variation across host grasses and plant parts, essential for understanding the endophyte-conferred defence extent. The patterns can be understood by considering endophyte growth within the plant and alkaloid mobility. Our study identifies research gaps, including the limited documentation of alkaloid presence in roots and the need to investigate the influence of different environmental conditions.