Host switching by an ambrosia beetle fungal mutualist: Mycangial colonization of indigenous beetles by the invasive laurel wilt fungal pathogen
Host switching by an ambrosia beetle fungal mutualist: Mycangial colonization of indigenous beetles by the invasive laurel wilt fungal pathogen
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DOI：
10.1111/1462-2920.16401
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发表时间：
2023-05-16
影响因子：
5.1
通讯作者：
Keyhani, Nemat O. O.
中科院分区：
文献类型：
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作者：
Joseph, Ross;Bansal, Kamaldeep;Keyhani, Nemat O. O.
神仙甲虫需要它们的真菌共生伙伴作为它们在树廊中栽培（养殖）的食物来源。虽然大多数真菌甲虫伴侣不会杀死它们栖息的寄主树木，但自从它们在2002年左右被引入（入侵）美国以来，入侵性甲虫Xyleborus glabratus已经将其共生伙伴（但植物致病）真菌Harringtonia lauricola传播给了它们，导致超过3亿棵树死亡。令人担忧的是，当地的甲虫已经被抓到携带月桂蚜。在这里，我们展示了H. lauricola对本地X. affinis ambrosia甲虫的mycangia的殖民化。采食后1小时内，月桂蚜的菌丝定植水平与本地X. affinis-R相似。Arxii真菌伴侣。随着时间的推移和去除真菌源后，真菌菌丝的占用是稳定的，但当有额外的真菌细胞可用时，真菌菌丝的占用表现出快速的更新。显微镜下观察到两个口前菌丝囊，大小约为100-200 × 25-50 μ m/个，入口通道狭窄，大小约为25-50 × 3-10 μ m。菌丝囊内的真菌经历了从丝状/囊胚生长到酵母样出芽的二态转变，膜结构发生改变。这些数据确定了月桂花甲虫mycinal定殖的特征，暗示转换是月桂花甲虫寄主转换到其他种类月桂花甲虫的机制。
Ambrosia beetles require their fungal symbiotic partner as their cultivated (farmed) food source in tree galleries. While most fungal-beetle partners do not kill the host trees they inhabit, since their introduction (invasion) into the United states around similar to 2002, the invasive beetle Xyleborus glabratus has vectored its mutualist partner (but plant pathogenic) fungus, Harringtonia lauricola, resulting in the deaths of over 300 million trees. Concerningly, indigenous beetles have been caught bearing H. lauricola. Here, we show colonization of the mycangia of the indigenous X. affinis ambrosia beetle by H. lauricola. Mycangial colonization occurred within 1 h of feeding, with similar levels seen for H. lauricola as found for the native X. affinis-R. arxii fungal partner. Fungal mycangial occupancy was stable over time and after removal of the fungal source, but showed rapid turnover when additional fungal cells were available. Microscopic visualization revealed two pre-oral mycangial pouches of similar to 100-200 x 25-50 mu m/each, with narrow entry channels of 25-50 x 3-10 mu m. Fungi within the mycangia underwent a dimorphic transition from filamentous/blastospore growth to yeast-like budding with alterations to membrane structures. These data identify the characteristics of ambrosia beetle mycangial colonization, implicating turnover as a mechanism for host switching of H. lauricola to other ambrosia beetle species.