Study On Adaptation Mechanism Of Mangrove Plants To High Salinity And Waterlogging

Mangrove plants are surviving in flooding,low oxygen and high salinity environment.In order to adapt these inter tidal environments,mangrove plants develop a series of adaption mechanisms.Kandelia obovata,Acanthus ilicifolius and Acanthus mollis were selected for further study.The results as follows:1.Kandelia obovata is the main mangrove species in the coastal beaches of southeastern China.We found that H2S had positive effects on the leaves of Kandelia obovata.(1)Photosynthesis-related proteins were significantly down-regulated under high salinity.Meanwhile,CPX ?(spot 26),RBCL(spot 9,16)and RCA(spot 11)were up-regulated by NaHS addition,indicated that H2S had positive effect on the photosynthetic efficiency and carbon assimilation process.(2)Exogenous H2S increased the activity of antioxidant enzymes under high salinity,and decreased the expression of cysteine protease(CP).CP was the key protease for programmed cell death,thus enhanced the salt tolerance of Kandelia obovata.(3)In addition,exogenous H2S supply alleviated salt tolerance by increasing the accumulation of proteins involved in primary metabolism(spot 36)and energy metabolism(spot 8,10,41,42),implied that the application of NaHS was beneficial for the energy supply.(4)The abundance of glutamine synthase was increased by exogenous H2S under high salinity,result in the promotion of the nitrogen-containing compounds synthesis.(5)1-aminocyclopropane-1-carboxylic acid synthase(ACS),which was the key protein in ethylene synthesis,was down-regulated by exogenous H2S under high salinity,resulting in the inhibition of ethylene synthesis.In addition,the up-regulated of NDPK protein accumulation maintained the balance of nucleotide metabolism in plant cells.2.The different waterlogging tolerance of relative species Acanthus ilicifolius and Acanthus mollis was studied by proteomics and transcriptome,that promoted the understanding of the molecular mechanism of mangrove plants to adapt the intertidal environment.(1)The Calvin cycle-related proteins were up-regulated to supply more energy to A.ilicifolius leaves.The stress response-related proteins were up-regulated(APX and SOD)to improve the adaptation of A.ilicifolius leaves under waterlogging stress.The inhibition of energy supply related pathways induced the waterlogging sensitivity of A.mollis leaves.(2)The content of monosaccharides and polysaccharides were increased by the anaerobic signals in A.ilicifolius roots under waterlogging stress.WRKY transcription factor,phenylpropane,and flavonoid metabolic pathway were also up-regulated in A.ilicifolius roots under waterlogging stress.The DEGs and DEPs of the AsA-GSH cycle,ethylene synthesis,and potassium channel were increased,promoting the adaptation of A.ilicifolius roots under waterlo gging treatment.(3)The ethanol fermentation pathway was up-regulated in the roots of A.mollis under waterlogging treatment,which produced the ethanol and damaged to the plasma membrane.The potassium channel-related genes were inhibited in the roots of A.mollis,which flowed more potassium ion out of the cell.The AsA-GSH cycle-related proteins were down-regulated in the root of A.mollis,resulting in the plant cell was negative influence by excess ROS.