Root exudation as functional trait involved in plant nutrition-use strategy classification and in shaping plant microbiota diversity and function

Date:
28
Tuesday
December
2021
Lecture / Seminar
Time: 11:30-12:30
Title: Zoom Guest Seminar
Location: https://weizmann.zoom.us/j/93885750016?pwd=blVnQ2phWDdlWTJ3UlVteVlYL1BkQT09 Meeting ID: 938 8575 0016 Password: 365291
Lecturer: Prof. Feth el Zahar Haichar
Organizer: Department of Plant and Environmental Sciences
Details: Biosciences Department, Institut National des Sciences Appliquées de Lyon
Abstract: Plants adopt a variety of life history strategies to succeed in the Earth’s di ... Read more Plants adopt a variety of life history strategies to succeed in the Earth’s diverse environments. Using functional traits which are defined as “morphological, biochemical, physiological, or phonological” characteristics measurable at the individual level, plants are classified according to their species’ adaptative strategies, more than their taxonomy, from fast growing plant species to slower-growing conservative species. These different strategies probably influence the input and output of carbon (C)- resources, from the assimilation of carbon by photosynthesis to its release in the rhizosphere soil via root exudation. However, while root exudation was known to mediate plant-microbe interactions in the rhizosphere, it was not used as functional trait until recently. In addition, no study analyzed the impact of plant nutritional strategy via root exudation quality and quantity on rhizosphere microbial activities and diversity. Here, we (i) assess whether root exudate levels are useful plant functional traits in the classification of plant nutrient-use strategies and (ii) determine using stable isotope probing (SIP) approach the impact of root exudates quality and quantity on active microbiota diversity and activity. For this purpose, six grass species distributed along a gradient of plant nutrient resource strategies, from conservative species, characterized by low nitrogen (N) uptake, a long lifespans and low root exudation level, to exploitative species, characterized by high rates of photosynthesis, rapid rates of N uptake were used. We show, for the first time, that root exudation rate can be used as a key functional trait in plant ecology studies and plant strategy classification. In addition, measurement of microbial activities revealed an increase in denitrification and respiration activities for microbial communities colonizing the root adhering soil of exploitative species. This increase of microbial activities results probably from a higher exudation rate and more diverse metabolites by exploitative plant species. Furthermore, our results demonstrate that plant nutrient resource strategies have a role in shaping active microbiota. We present evidence demonstrating that plant nutrient use strategies shape active microbiota involved in root exudate assimilation and soil organic matter degradation via root exudation.
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