Metabolites and microbes of Tetrastigma: the ecology of host choice in Rafflesia and potential applications in ex situ conservation of the worlds largest flower

四柱花的代谢物和微生物：大王花寄主选择的生态学及其在世界最大花卉迁地保护中的潜在应用

• 批准号: 2204938
• 负责人: Jeanmaire Molina
• 金额: $ 27.96万
• 依托单位: Long Island University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-07-01 至 2023-10-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2204938&HistoricalAwards=false
• 关键词: Metabolites; microbes; Tetrastigma; ecology; host

Amidst the dwindling rainforests of Southeast Asia, Rafflesia’s rare but massive malodorous maroon flower stands out, deceptively luring carrion flies, hence the common name, “corpse flower”. Unlike most plants, Rafflesia is an obligate plant parasite, bereft of stems, roots, and leaves, and devoid of photosynthesis, which supposedly defines plants. Solely infecting the tropical grape vine Tetrastigma—and only a few species of it—it is unknown why. Despite being a charismatic icon of conservation, there is no western botanic garden that has grown Rafflesia because it is still virtually unknown how. This project aims to understand the ecology of Rafflesia’s host choice—what molecules and microbes in Tetrastigma hosts make them susceptible to Rafflesia infection compared to non-hosts, and how this basic information may be used to guide propagation. Conversely, this project will yield data on the metabolic and microbial processes underlying enhanced host immune function in Tetrastigma, why certain species are not parasitized by Rafflesia, and how this knowledge can be applied in grapes, Tetrastigma’s close relative, to resist parasitic infections. Moreover, the project will engage underrepresented students and catalyze their careers in biodiversity science, while providing capacity building to indigenous communities in the Philippines where samples will be collected. This understanding of the fundamental science may one day allow Rafflesia—the panda of the plant world—to be in full bloom in botanic gardens, fostering education and conservation. Timing is critical, because once extinct, the corpse flower can no longer be revived.Rafflesia (Rafflesiaceae, Malpighiales) is an endophytic holoparasite, completely dependent on its host vine Tetrastigma (Vitaceae, Vitales) for nutrition, living inside it throughout its life and only emerging to flower. However, not all Tetrastigma species support a Rafflesia infection. The project aims to understand the ecology of Rafflesia’s host choice, focusing on the chemistry and microbiota unique to infected host species through metabolite profiling and metagenomic analysis. Comparing multiple Rafflesia-Tetrastigma species systems will clarify common patterns that make certain Tetrastigma spp. hosts versus non-hosts, reveal how different Rafflesia spp. similarly alter host ecology during an infection, as well as decipher the metabolic and microbial idiosyncrasies between species systems that could explain Rafflesia’s host choice. In agriculture, grafting success is dependent on how closely related the scion and rootstock are, but how does Rafflesia, belonging to a different order from its host, successfully evade host immunity, and how can this basic information be applied in preventing graft incompatibility in crops? Resulting data will also reveal the extent of convergent evolution compared to other host-parasite systems, if there are similar host-degrading metabolites in the evolution of heterotrophy in disparate lineages of parasitic plants. These data will elucidate host chemotypes and plant-regulating microbial endophytes that could facilitate and sustain a Rafflesia infection, and consequently, Rafflesia horticulture for ex situ conservation while gaining insights that could potentially benefit other agricultural crops.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

在东南亚日益减少的热带雨林中，莱佛莱稀有但巨大的臭气熏天的栗色花脱颖而出，骗人地引诱腐尸苍蝇，因此有了一个俗称：死尸花。与大多数植物不同，Rafflesia是一种专性寄生植物，没有茎、根和叶，也没有光合作用，光合作用被认为是植物的特征。仅感染热带葡萄藤--而且只有少数几种--的原因尚不清楚。尽管是一个富有魅力的自然保护标志，但西方植物园中还没有种植莱芙兰的植物，因为它是如何种植的实际上仍然是未知的。该项目旨在了解Rafflesia选择寄主的生态--与非寄主相比，Tetrastigma寄主中的哪些分子和微生物使它们容易感染Rafflesia，以及这些基本信息如何用于指导繁殖。相反，这个项目将产生关于四斑叶蝉增强宿主免疫功能的代谢和微生物过程的数据，为什么某些物种不会被Rafflesia寄生，以及如何将这一知识应用于四角虫的近亲葡萄，以抵抗寄生虫感染。此外，该项目将吸引代表性不足的学生参与，并促进他们在生物多样性科学方面的职业生涯，同时向菲律宾的土著社区提供能力建设，在那里收集样本。这种对基础科学的理解有朝一日可能会让植物世界的熊猫Rafflesia在植物园中盛开，促进教育和保护。时机很关键，因为一旦灭绝，尸花就不能再复活。莱夫莱斯(Rafflesiaceae，Malighiales)是一种内生全寄生寄生虫，完全依赖其寄主藤本植物Tetrastigma(葡萄科，Vitales)获取营养，一生都生活在它的体内，只有在开花时才会出现。然而，并不是所有的四色线虫都支持莱夫莱斯感染。该项目旨在了解Rafflesia寄主选择的生态学，通过代谢物图谱和元基因组分析，重点研究受感染寄主物种特有的化学和微生物区系。通过对多个Rafflesia-Tetrastigma种系的比较，可以明确确定Tetrastigma spp.的共同模式。寄主和非寄主，揭示了不同的Rafflesia sp.同样，在感染期间改变寄主生态，以及破译物种系统之间的新陈代谢和微生物特性，可以解释Rafflesia的寄主选择。在农业上，嫁接的成功取决于接穗和砧木的亲缘关系有多密切，但与寄主不同目的莱佛兰如何成功地逃避寄主免疫，以及如何将这些基本信息应用于防止作物的嫁接不亲和性？由此产生的数据还将揭示与其他寄主-寄生系统相比的趋同进化的程度，如果在不同的寄生植物谱系的异养进化中存在类似的寄主降解代谢物。这些数据将阐明寄主化学类型和植物调节微生物内生菌，它们可以促进和维持莱夫莱斯的感染，从而为迁地保护的莱佛莱园艺提供帮助，同时获得可能使其他农业作物受益的见解。这一奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

项目成果

The seed transcriptome of Rafflesia reveals horizontal gene transfer and convergent evolution: Implications for conserving the world's largest flower

• DOI: 10.1002/ppp3.10370
• 发表时间: 2023-04
• 期刊: PLANTS, PEOPLE, PLANET
• 作者: Jeanmaire Molina;Adhityo Wicaksono;T. Michael;S. Kwak;Ronniel D Pedales;Zoé Joly-Lopez;Semar Petrus;Allen Mamerto;Brian Tomek;Sumaya M. Ahmed;Venkatasivasankar Maddu;Kristina Yakubova;D. Tandang;J. Morin;So-Yon Park;Hyun‐Oh Lee;W. McLaughlin;Kyle Wallick;James Adams;A. Novy;S. Pell;M. Purugganan