Reactive Sulfur Species Interact with Other Signal Molecules in Root Nodule Symbiosis in Lotus japonicus.

Toshiki Uchiumi,Mitsutaka Fukudome,Ei-Ichi Murakami,Haruka Ishizaki,Ken-Ichi Osuki,Hazuki Shimada,Nahoko Uchi,Masayoshi Kawaguchi

doi:10.3390/antiox9020145

Toshiki Uchiumi, Mitsutaka Fukudome + Show 6 more

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https://doi.org/10.3390/antiox9020145

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Abstract

Reactive sulfur species (RSS) function as strong antioxidants and are involved in various biological responses in animals and bacteria. Few studies; however, have examined RSS in plants. In the present study, we clarified that RSS are involved in root nodule symbiosis in the model legume Lotus japonicus. Polysulfides, a type of RSS, were detected in the roots by using a sulfane sulfur-specific fluorescent probe, SSP4. Supplying the sulfane sulfur donor Na2S3 to the roots increased the amounts of both polysulfides and hydrogen sulfide (H2S) in the roots and simultaneously decreased the amounts of nitric oxide (NO) and reactive oxygen species (ROS). RSS were also detected in infection threads in the root hairs and in infected cells of nodules. Supplying the sulfane sulfur donor significantly increased the numbers of infection threads and nodules. When nodules were immersed in the sulfane sulfur donor, their nitrogenase activity was significantly reduced, without significant changes in the amounts of NO, ROS, and H2S. These results suggest that polysulfides interact with signal molecules such as NO, ROS, and H2S in root nodule symbiosis in L. japonicus. SSP4 and Na2S3 are useful tools for study of RSS in plants.

Highlights

Nitric oxide (NO), reactive oxygen species (ROS), and hydrogen sulfide (H2 S) function as signal molecules in physiological responses, including germination, stomatal regulation, and photosynthesis, and in biotic/abiotic stress responses in plants [1,2,3,4]
We provide evidence that (1) Reactive sulfur species (RSS) are detectable in the roots of Lotus japonicus by using a specific fluorescent probe, (2) RSS are involved in Mesorhizobium–Lotus symbiosis, and (3) they collaborate with these signal molecules
We provide evidence that (1) RSS are detectable in the roots of Lotus japonicus by using a specific fluorescent probe, (2) RSS are involved in Exogenous Na2 S3 affected concentrations of nitric oxide (NO), ROS, and H2 S in L. japonicus, as reported in animals and bacteria [60,61]

Summary

Introduction

Nitric oxide (NO), reactive oxygen species (ROS), and hydrogen sulfide (H2 S) function as signal molecules in physiological responses, including germination, stomatal regulation, and photosynthesis, and in biotic/abiotic stress responses in plants [1,2,3,4]. NO reacts with ROS to form reactive nitric oxide species such as peroxynitrite, which participates in protein activity by posttranslational modification such as tyrosine nitration [5,6,7]. Both NO and ROS regulate expression of genes related to stress responses in plants via primary metabolism and plant hormone signaling [8,9,10]. Plants produce NO and ROS in response to infection by microbes [2,5,17,18,19,20], and NO and ROS production is part of the process for establishment of plant–bacteria symbioses [21,22]

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