H₂S Signal Regulates The Growth Of Arabidopsis Hypocotyls In Response To Red Light

Light is vital to plants,as an energy source for photosynthesis and as a regulator of plant photomorphogenesis.Photosensitive action factors(PIFs)can directly interact with red light receptor photosensitive pigment(PHY)to regulate the expression of related genes.Hydrogen sulfide(H₂S)has been reported to be involved in regulating plant photomorphogenesis as an intracellular gas signaling molecule.In this paper,we investigated whether H₂S signal responds to red light and its role in photomorphogenesis in Arabidopsis thaliana.This thesis in arabidopsis wild-type Col,red light receptor mutants phy A and phy B and phytochrome function factor pif1,pif4 and pif Q(pif1,3,4,5,4mutant),and the expression of mutant PIF1(oe1)and the expression of mutant PIF4(oe4)as experiment materials,respectively in red light treatment after 5,10 and 15 min and sampling,testing,producing rate and the main content of H₂S produced changes of enzymes and genes encoding transcription level;The effects of H₂S on cotyledon elongation and cotyledon decoloration were compared under dark and red light conditions.The experimental results are as follows:(1)The effect of red light on the H₂S content of Arabidopsis thaliana cotyls:H₂S content of wild-type COL and mutants oe1 and oe4 was significantly increased after 10 min of red light irradiation,while H₂S content of pif4 was significantly increased after 15 min of red light irradiation,slightly lagging that of COL;The H₂S content in the mutant phy A,phy B,pif1 and pif Q was not induced by red light.(2)The effect of red light on H₂S production of Arabidopsis cotyls:H₂S production of wild-type COL and mutant pif Q was significantly increased after10 min of red light irradiation.The H₂S yields of the mutant phy A,phy B,oe1,pif1,oe4 and pif4 were not increased by red light.(3)AT-LCD phosphorylation:Prokaryotic expression of recombinant His-LCD protein can undergo phosphorylation modification in vitro.(4)The effect of red light on the transcription level of endogenous H₂S-producing enzyme encoding genes in Arabidopsis thaliana:Ch IP results showed that PIF1 and PIF4 could bind to LCD gene promoter under dark conditions;Red light can activate the expression of H₂S-producing enzyme genes.(5)The effect of exogenous H₂S on hypocotyl elongation of Arabidopsis thaliana:there was no significant difference in hypocotyl length between5?mol/L H₂S treatment and control group;Exogenous H₂S can significantly inhibit the hypocotyl elongation of Arabidopsis thaliana seedlings under dark or red light culture,and the higher the concentration,the stronger the inhibition affects.(6)The effect of exogenous H₂S on the decoloration of hypocotyl cotyledon of Arabidopsis thaliana under red light:5?mol/L exogenous H₂S can accelerate the decoloration of phy A,phy B and lcd/des1 of mutant,but the decoloration rate of wild-type COL is slightly lower than that of control group.The exogenous H₂S of 20?80?mol/L made the decolorization rate slow down rapidly.In conclusion,H₂S signaling is involved in red receptor-mediated photomorphogenesis in Arabidopsis,including phosphorylation of endogenous H₂S-producing enzyme LCD protein and changes in enzyme gene expression regulated by photosensitive pigment interaction factor PIF.