Root exudates drive soil-microbe-nutrient feedbacks in response to plant growth.

Affiliation

Zhao M(1), Zhao J(2), Yuan J(1), Hale L(3)(4), Wen T(1), Huang Q(1), Vivanco JM(5), Zhou J(4)(6)(7), Kowalchuk GA(8), Shen Q(1).
Author information:
(1)Jiangsu Provincial Key Lab for Organic Solid Waste Utilization, Jiangsu Collaborative Innovation Center for Solid Organic Wastes, Educational Ministry Engineering Center of Resource-saving fertilizers, Nanjing Agricultural University, Nanjing, China.
(2)School of Geography Science, Nanjing Normal University, Nanjing, China.
(3)USDA, Agricultural Research Service, San Joaquin Valley Agricultural Sciences Center, Parlier, California, USA.
(4)Institute for Environmental Genomics, Department of Microbiology and Plant Biology, and School of Civil Engineering and Environmental Sciences, University of Oklahoma, Norman, Oklahoma, USA.
(5)Department of Horticulture and Landscape Architecture and Center for Rhizosphere Biology, Colorado State University, Fort Collins, Colorado, USA.
(6)State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing, China.
(7)Earth and Environmental Sciences, Lawrence Berkeley National Laboratory, Berkeley, California, USA.
(8)Ecology and Biodiversity Group, Department of Biology, Institute of Environmental Biology, Utrecht University, Utrecht, The Netherlands.

Abstract

Although interactions between plants and microbes at the plant-soil interface are known to be important for plant nutrient acquisition, relatively little is known about how root exudates contribute to nutrient exchange over the course of plant development. In this study, root exudates from slow- and fast-growing stages of Arabidopsis thaliana plants were collected, chemically analysed and then applied to a sandy nutrient-depleted soil. We then tracked the impacts of these exudates on soil bacterial communities, soil nutrients (ammonium, nitrate, available phosphorus and potassium) and plant growth. Both pools of exudates shifted bacterial community structure. GeoChip analyses revealed increases in the functional gene potential of both exudate-treated soils, with similar responses observed for slow-growing and fast-growing plant exudate treatments. The fast-growing stage root exudates induced higher nutrient mineralization and enhanced plant growth as compared to treatments with slow-growing stage exudates and the control. These results suggest that plants may adjust their exudation patterns over the course of their different growth phases to help tailor microbial recruitment to meet increased nutrient demands during periods demanding faster growth.