Sword Gregory A, Tessnow Ashley, Ek-Ramos Maria Julissa
Department of Entomology, Texas A&M University, College Station, Texas, USA.
Ecology and Evolutionary Biology Interdisciplinary Program, Texas A&M University, College Station, Texas, USA.
Insect Sci. 2017 Dec;24(6):1003-1014. doi: 10.1111/1744-7917.12461. Epub 2017 May 18.
All plants including cotton host a wide range of microorganisms as endophytes. There is a growing appreciation of the prevalence, ecological significance and management potential of facultative fungal endophytes in protecting plants from pests, pathogens and environmental stressors. Hemipteran sucking bugs have emerged as major pests across the U.S. cotton belt, reducing yields directly by feeding on developing reproductive structures and indirectly by vectoring plant pathogens. We used no-choice and simultaneous choice assays to examine the host selection behavior of western tarnished plant bugs (Lygus hesperus) and southern green stink bugs (Nezara viridula) in response to developing flower buds and fruits from cotton plants colonized by 1 of 2 candidate beneficial fungal endophytes, Phialemonium inflatum or Beauveria bassiana. Both insect species exhibited strong negative responses to flower buds (L. hesperus) and fruits (N. viridula) from plants that had been colonized by candidate endophytic fungi relative to control plants under both no-choice and choice conditions. Behavioral responses of both species indicated that the insects were deterred prior to contact with plant tissues from endophyte-colonized plants, suggesting a putative role for volatile compounds in mediating the negative response. Our results highlight the role of fungal endophytes as plant mutualists that can have positive effects on plant resistance to pests.
包括棉花在内的所有植物都有各种各样的微生物作为内生菌。人们越来越认识到兼性真菌内生菌在保护植物免受害虫、病原体和环境压力方面的普遍性、生态意义和管理潜力。半翅目吸食性害虫已成为美国棉花带的主要害虫，它们通过取食发育中的生殖结构直接降低产量，并通过传播植物病原体间接降低产量。我们使用无选择和同时选择试验，来研究西方牧草盲蝽（Lygus hesperus）和绿蝽（Nezara viridula）对由两种候选有益真菌内生菌之一——膨胀瓶霉（Phialemonium inflatum）或球孢白僵菌（Beauveria bassiana）定殖的棉花植株上发育的花蕾和果实的寄主选择行为。在无选择和选择条件下，相对于对照植株，这两种昆虫对已被候选内生真菌定殖的植株上的花蕾（西方牧草盲蝽）和果实（绿蝽）均表现出强烈的负面反应。这两种昆虫的行为反应表明，在接触来自内生菌定殖植株的植物组织之前，它们就受到了抑制，这表明挥发性化合物在介导这种负面反应中可能发挥了作用。我们的研究结果突出了真菌内生菌作为植物共生体的作用，其对植物抗虫性可产生积极影响。
