Molecular Cloning Of A Novel OASTL/LCD Gene From Tomato And Hydrogen Sulfide Is Involved In Itric Oxide-Induced Tomato Lateral Root Formation

Exogenous hydrogen sulfide (H2S) has been reported to participate in mult-physical progresses in plant, while whether and how endogenous H2S, as a signal molecular, modulate the root growth in plants remains unclear. Therefore, the aim of this study was to explore the molecular mechanism of H2S-promoted lateral root formation in tomato seedlings which mainly focued on the investigation of the interplay between H2S and nitric oxide (NO). The results are as follows:(1) The estimatied Sl_OASTL/LCD gene was obtained using EST (expressed sequence tags) database. Based on the bioinformatics analysis, we supposed that NO could boost DCD and Sl_OASTL/LCD to synthesis H2S in tomato.(2) NO can promote tomato lateral root formation from the evidences that the average number of tomato lateral root was increased with sodium nitroprusside (SNP) pretreatment, while it was decreased with 2-(4-carboxy-2-phenyl)-4,4,5,5-tetramethylinidazoline-l-oxyl-3-oxide (cPTIO) pretreatment.H2S can promote tomato lateral root formation from the evidences that the average number of tomato lateral root, the H2S fluorescence density and the expression of CYCD3; 1, CDKA1, ARF4, ARF7 were increased with sodium hydrosulfide (NaHS) pretreatment, while they were decreased with DL-propargylglycine (PAG) or hypotaurine (HT) pretreatment.(3) The concentration of endogenous H2S was increased with sodium nitroprusside (SNP) pretreatment. However, these promotion effects could be abolished with the application of DL-propargylglycine (PAG) or hypotaurine (HT). Treatment with 2-(4-carboxy-2-phenyl)-4,4,5,5-tetramethylinidazoline-l-oxyl-3-oxide (cPTIO) would not abolish the promotion effect of NaHS, suggesting that H2S acts downstream of NO in regulating tomato lateral root formation.In comparison with NO and H2S signal moleculars, Ca2+ was also found to have involved in the process of tomato lateral root formation. And Ca2+ acts downstream of H2S in tomato lateral root formation process from the evidences that the average number of tomato lateral root, the H2S fluorescence density and the expression of CYCD3;1, CDKA1, ARF4, ARF7 were increased with sodium hydrosulfide (NaHS) pretreatment, while these promotion effects could be abolished with the application of lanthanum (La3+) or ethylenebis(oxyethylenenitrilo)tetraacetic acid (EGTA).In conclusion, our data suggested that the estimated Sl_OASTL/LCD gene was firstly obtained and supposed to be regulated by NO to synthesis H2S in tomato. H2S acting between NO and Ca2+is one of the possible signaling pathwany in the complicated network for the regulation of tomato lateral root formation.