Symbionts in Mucuna pruriens stimulate plant performance through nitrogen fixation and improved phosphorus acquisition

刺毛黎豆共生体通过固氮和提高磷吸收来提高植株的生长表现 南非主要以热带稀树草原和草原生态系统为主，这些生态系统具有酸性和营养缺乏的属性，特别是磷和氮素的缺乏。刺毛黎豆(Mucuna pruriens)是在大多数非洲国家广泛存在的一种本土豆科植物，该 植物可以抵御这些不利的土壤条件。豆科植物在世界上许多国家具有药用价值，也被用于土壤施肥。尽管已有文献记载了在营养胁迫生态系统中刺毛黎豆的生长和建植，但尚未对其在磷缺乏条件下的共生互作、氮源偏好和与生长相关的碳成本进行研究。在本研究中，我们确定了微生物共生体对磷缺乏条件下的刺毛黎豆氮营养和生长相关的碳成本的影响。我们从4个不同的地理位置采集微生物接种土壤，然后将种子在这些天然土壤中发芽，在根瘤发育的早期，将幼苗转移到无菌石英砂中，并提供不同磷 浓度的营养培养基。16S RNA序列结果显示，在不考虑磷浓度的情况下，Burkholderia sp., Paenibacillus sp.和Bacillus 均有分枝。尽管磷缺乏导致总生物量/生长下降，但根系生物量、根瘤数量和碳成本增加。低磷供给的幼树丛枝菌根真菌根系定殖率最高。刺毛黎豆中，大气中的氮与磷水平呈正相关关系，幼树对大气氮素和土壤氮素具有双重依赖，低磷植株对土壤氮素的依赖程度增加。因此，在磷缺乏的情况下，刺毛黎豆表现出不同的形态和微生物共生关系。     

Evolution of a non-flying mammal-dependent pollination system in Asian Mucuna (Fabaceae)

Pollinator shifts are often related to speciation in angiosperms, and the relationship between them has been discussed in several plant taxa. Although limited information on plants pollinated by non-flying mammals in Central and South America and Africa is available, related research has not been conducted in Asia. Herein, I summarize the available knowledge of pollination in Asian Mucuna (Fabaceae), a genus mainly distributed in the tropics, and discuss the evolution of plants pollinated by non-flying mammals in Asia. Nineteen pollinator species have been recorded and pollination systems have been categorized into four types. An examination of the relationship between Mucuna species and their pollinators from the lineage perspective revealed that all species in Mucuna, subgenus Macrocarpa, which are distributed in Asia, are pollinated exclusively by non-flying mammals. Additionally, plants pollinated by non-flying mammals were found to have diverged from bat-pollinated and non-flying mammal-pollinated plants, while plants pollinated by non-flying mammals have evolved multiple times. This is a unique example of evolutionary transition. I hypothesize that the diversification of squirrel species in tropical Asia may have led to the speciation and diversification of Mucuna in Asia. Furthermore, the behavioural and ecological characteristics of bats and birds in Asia differ from the characteristics of those in other regions, implying that Asian Mucuna species do not rely on bat or bird pollinators. The adaptation of floral characteristics to pollinators is not well understood in Asia. Mammal-pollinated plants in Asia may have evolved differently from those in other regions and have unique pollination systems.