In Site Bioimaging of Hydrogen Sulfide Uncovers Its Pivotal Role in Regulating Nitric Oxide-Induced Lateral Root Formation

Yan-Jun Li,Zhi-Qi Shi,Fengxiang X Han,Ming Xian,Jian Chen,Li-Gang Zhou,Li-Jun Gan,Hiroyasu Nakano

doi:10.1371/journal.pone.0090340

Abstract

Hydrogen sulfide (H2S) is an important gasotransmitter in mammals. Despite physiological changes induced by exogenous H2S donor NaHS to plants, whether and how H2S works as a true cellular signal in plants need to be examined. A self-developed specific fluorescent probe (WSP-1) was applied to track endogenous H2S in tomato (Solanum lycopersicum) roots in site. Bioimaging combined with pharmacological and biochemical approaches were used to investigate the cross-talk among H2S, nitric oxide (NO), and Ca2+ in regulating lateral root formation. Endogenous H2S accumulation was clearly associated with primordium initiation and lateral root emergence. NO donor SNP stimulated the generation of endogenous H2S and the expression of the gene coding for the enzyme responsible for endogenous H2S synthesis. Scavenging H2S or inhibiting H2S synthesis partially blocked SNP-induced lateral root formation and the expression of lateral root-related genes. The stimulatory effect of SNP on Ca2+ accumulation and CaM1 (calmodulin 1) expression could be abolished by inhibiting H2S synthesis. Ca2+ chelator or Ca2+ channel blocker attenuated NaHS-induced lateral root formation. Our study confirmed the role of H2S as a cellular signal in plants being a mediator between NO and Ca2+ in regulating lateral root formation.

Highlights

Hydrogen sulfide (H2S) is considered as the third gasotransmitter in medical biology after nitric oxide (NO) and carbon monoxide (CO) [1]
Analysis of fluorescent density showed that several sulfur compounds (e.g. NaHSO4, Na2SO4, Na2S2O4, and sulfonamide) had little fluorescence, but their values are too small as compared with NaHS (Figure 2d). These results suggested that WSP-1 could be used for the selective detection of endogenous H2S in tomato roots
Endogenous H2S was involved in lateral root formation we investigate the link between lateral root emergency and endogenous H2S

Summary

Introduction

Hydrogen sulfide (H2S) is considered as the third gasotransmitter in medical biology after nitric oxide (NO) and carbon monoxide (CO) [1]. Two multifunctional pyridoxal 59-phosphate (PLP)-dependent enzymes, cystathionine c-lyase (CSE) and cystathionine b-synthase (CBS), are demonstrated to be the major sources of endogenous H2S production [5]. In plants H2S is considered to be a by-product from cysteine desulfuration catalyzed by L-cysteine desulfhydrase (LCD, EC4.4.1.1) and Dcysteine desulfhydrase (DCD, EC4.4.1.15), both of which belonging to the PLP protein family [7]. Both genes (LCD and DCD) have been characterized in Arabidopsis [8]. A recent study suggests that O-acetylserine(thiol)lyase (OASTL), a cysteine synthase-like protein, possesses the activity of cysteine desulfuration [9]

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