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Never too many? How legumes control nodule numbers
Author(s) -
MORTIER VIRGINIE,
HOLSTERS MARCELLE,
GOORMACHTIG SOFIE
Publication year - 2012
Publication title -
plant, cell and environment
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.646
H-Index - 200
eISSN - 1365-3040
pISSN - 0140-7791
DOI - 10.1111/j.1365-3040.2011.02406.x
Subject(s) - rhizobia , nitrogen fixation , limiting , root nodule , nodule (geology) , symbiosis , biology , nitrogen , nutrient , plant growth , agronomy , nitrogenase , bacteria , chemistry , ecology , engineering , mechanical engineering , paleontology , organic chemistry , genetics
Restricted availability of nitrogen compounds in soils is often a major limiting factor for plant growth and productivity. Legumes circumvent this problem by establishing a symbiosis with soil‐borne bacteria, called rhizobia that fix nitrogen for the plant. Nitrogen fixation and nutrient exchange take place in specialized root organs, the nodules, which are formed by a coordinated and controlled process that combines bacterial infection and organ formation. Because nodule formation and nitrogen fixation are energy‐consuming processes, legumes develop the minimal number of nodules required to ensure optimal growth. To this end, several mechanisms have evolved that adapt nodule formation and nitrogen fixation to the plant's needs and environmental conditions, such as nitrate availability in the soil. In this review, we give an updated view on the mechanisms that control nodulation.