The effect of exogenous nitrate on LCO signalling, cytokinin accumulation, and nodule initiation in Medicago truncatula
Xiao, Ting Ting
Wardhani, Titis A.K.
van Zeijl, Arjan
KAUST DepartmentCenter for Desert Agriculture, Biological and Environmental Sciences and Engineering (BESE), King Abdullah University of Science and Technology (KAUST), Thuwal, 23955-6900, Saudi Arabia
Permanent link to this recordhttp://hdl.handle.net/10754/670231
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AbstractNitrogen fixation by rhizobia is a highly energy-demanding process. Therefore, nodule initiation in legumes is tightly regulated. Environmental nitrate is a potent inhibitor of nodulation. However, the precise mechanism by which this agent (co)regulates the inhibition of nodulation is not fully understood. Here, we demonstrate that in Medicago truncatula the lipo-chitooligosaccharideinduced accumulation of cytokinins is reduced in response to the application of exogenous nitrate. Under permissive nitrate conditions, perception of rhizobia-secreted signalling molecules leads to an increase in the level of four cytokinins (i.e., iP, iPR, tZ, and tZR). However, under high-nitrate conditions, this increase in cytokinins is reduced. The ethylene-insensitive mutant Mtein2/sickle, as well as wild-type plants grown in the presence of the ethylene biosynthesis inhibitor 2-aminoethoxyvinyl glycine (AVG), is resistant to the inhibition of nodulation by nitrate. This demonstrates that ethylene biosynthesis and perception are required to inhibit nodule organogenesis under high-nitrate conditions.
CitationGühl, K., Holmer, R., Xiao, T. T., Shen, D., Wardhani, T. A. K., Geurts, R., … Kohlen, W. (2021). The Effect of Exogenous Nitrate on LCO Signalling, Cytokinin Accumulation, and Nodule Initiation in Medicago truncatula. Genes, 12(7), 988. doi:10.3390/genes12070988
SponsorsThis work was supported by NWO-VICI (865.13.001) to R.G and NWO-VENI (863.15.010) to W.K.
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