欧亚国际

最近，来自比利时根特大学的科学家，利用SMO公司构建的高通量表型成像平台发表了题为Shifts in the rhizobiome during consecutive in planta enrichment for phosphate-solubilizing bacteria differentially affect maize P status的文章，文章发表在Microbial Biotechnology上，http://doi.org/10.1111/1751-7915.13824，这已经是该团队利用SMO构建的高通量表型成像系统发表的第7篇文章。该平台称为PathoViewer，是一款高通量植物表型成像平台，使用了高分辨率图像在可控条件下对植物进行高通量表型成像。在植物表型组研究中，通量是一个不可忽视的因素。该系统配备有6MP-16 bit的相机系统以及各种光学滤波轮，有广泛用途，例如测量叶绿素荧光、红色荧光蛋白、绿色荧光蛋白、自荧光、RGB改进花青素反射指数以及叶绿素指数等。系统为自动系统，用于测量植物或植物部分的生物或非生物胁迫。Pathoviewer组合了RGB, 叶绿素荧光、花青素、NIR和GFP/RFP图像处理，对生物和非生物胁迫的影响进行成像。这些相机也可为研究人员采集植物科学相关信息，另外还可对表型特征可视化。

A.Experimental design of enrichments(E), enriched cultures and plant and bacterial material obtained in a validation experiment/*(V).RSS: Rhizosphere start suspension;Bn: bacterial suspension isolated from enrichmentn.

B.Overview of the in planta validation experiment housed in an acclimatized growth chamber, provided with a camera for multispectral imaging. Detailed colour image and false colour image of anthocyanin (mARI) and chlorophyll fluorescence (Fv/Fm) of detached leaves of a positive control (supplied with soluble P) and a negative control (supplied with insoluble P).

A. False colour image of a maize plant (top view) in time, indicating the emerging of anthocyanin accumulation from day 17 onwards. Dark pixels represent low mARI values (low anthocyanin content), purple to white pixels represent high mARI values (high anthocyanin content).

B. Proportional distribution of leaf pixels in mARI classes. The two mARI classes are based on the 95% confidence interval of plants under full Hoagland solution (= Class I), as these plants were not under P deficiency and therefore showed the optimal phenotype. Error bars denote SD. Significant differences after a two-sample t-test are indicated by letters above the stacked diagrams.

C. Plant P content measured through ICP-OES. Error bars denote S.

D. Mean P contents were compared to a threshold of 5000 mg P per kg dried plant and significant differences as per one-sample t-test are indicated with ¥ (P content > 5000) and # (P content < 5000).

Positive control: uninoculated plants supplied with soluble P (KH2PO4); Negative control: uninoculated plants supplied with insoluble P (FeP:AlP); V-Pn: plants inoculated with RSS (V-P1) or E-B1-3 (V-P2-4), growth substrate supplied with insoluble P (FeP:AlP).

Shifts in the rhizobiome during consecutive in planta enrichment for phosphate-solubilizing bacteria differentially affect maize P status

Noémie De Zutter, Maarten Ameye, Jane Debode, Caroline De Tender, Sarah Ommeslag, Jan Verwaeren, Pieter Vermeir, Kris Audenaert, Leen De Gelder

First published: 22 May 2021 

http://doi.org/10.1111/1751-7915.13824

Summary

Phosphorus (P) is despite its omnipresence in soils often unavailable for plants. Rhizobacteria able to solubilize P are therefore crucial to avoid P deficiency. Selection for phosphate-solubilizing bacteria (PSB) is frequently done in vitro; however, rhizosphere competence is herein overlooked. Therefore, we developed an in planta enrichment concept enabling simultaneous microbial selection for P-solubilization and rhizosphere competence. We used an ecologically relevant combination of iron- and aluminium phosphate to select for PSB in maize (Zea mays L.). In each consecutive enrichment, plant roots were inoculated with rhizobacterial suspensions from plants that had grown in substrate with insoluble P. To assess the plants’ P statuses, non-destructive multispectral imaging was used for quantifying anthocyanins, a proxy for maize’s P status. After the third consecutive enrichment, plants supplied with insoluble P and inoculated with rhizobacterial suspensions showed a P status similar to plants supplied with soluble P. A parallel metabarcoding approach uncovered that the improved P status in the third enrichment coincided with a shift in the rhizobiome towards bacteria with plant growth-promoting and P-solubilizing capacities. Finally, further consecutive enrichment led to a functional relapse hallmarked by plants with a low P status and a second shift in the rhizobiome at the level of Azospirillaceae and Rhizobiaceae.