Journal of Plant Ecology ›› 2021, Vol. 14 ›› Issue (2): 310-322.DOI: 10.1093/jpe/rtaa098

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  • 收稿日期:2020-03-30 修回日期:2020-04-25 接受日期:2020-11-21 出版日期:2021-03-01 发布日期:2021-03-08

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

Anathi Magadlela1, *, Nokhetho Makhaye1 and María Pérez-Fernández2   

  1. 1 School of Life Sciences, College of Agriculture, Engineering and Science, University of KwaZulu-Natal (Westville Campus), Private Bag X54001, Durban 4000, South Africa, 2 Deparment of Physical, Chemical and Natural Systems, Universidad Pablo de Olavide, Carretera de Utrera Km 1, 41013 Seville, Spain

    *Corresponding author. E-mail: anathimagadlela@icloud.com
  • Received:2020-03-30 Revised:2020-04-25 Accepted:2020-11-21 Online:2021-03-01 Published:2021-03-08

摘要: 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。

关键词: 刺毛黎豆, 磷缺乏, 生物固氮, 氮源偏好, 碳成本

Abstract:

Aims

South Africa is mainly dominated by savanna and grasslands ecosystems which have been previously reported to be acidic and nutrient deficient, specifically with regard to phosphorus (P) and nitrogen (N). Mucuna pruriens (L.) DC, commonly known as velvet bean, is an indigenous legume in most African countries and has been reported to withstand these adverse soil conditions. The legume is used in many countries of the world for their medicinal value as well as for soil fertilization purposes. Although there are reports on M. pruriens growth and establishment in nutrient stressed ecosystems, no investigation has been conducted on M. pruriens symbiotic interactions, N source preference and associated growth carbon costs when subjected to P deficiency. In this study, we determined the impact of microbial symbionts on N nutrition and growth carbon costs of M. pruriens under P deficiency.

Methods

Microbe inoculation soils were collected from four geographical distinct KwaZulu-Natal locations. Thereafter, seeds were germinated in these natural soils and in early stages of nodule development, then seedlings were transferred in sterile quartz sand and supplied with Long Ashton nutrient media with varying P concentrations.

Important Findings

The 16S RNA sequence results revealed that M. pruriens was nodulated by Burkholderia sp., Paenibacillus sp. and Bacillus irrespective of P concentrations. Even though P deficiency resulted in decreased overall biomass/growth, the root biomass, nodule number and carbon costs increased. In addition, low P supplied saplings showed the highest arbuscular mycorrhiza fungi percentage root colonization. In M. pruriens, nitrogen derived from atmosphere had a positive correlation with P level and the saplings had a dual reliance on atmospheric derived N and soil derived N with increased reliance on soil N in low P supplied plants. Therefore, M. pruriens exhibited different morphological and microbial symbiosis when subjected to P deficiency.

Key words: Mucuna pruriens, P deficiency, biological N fixation, N source preference, C costs