The Trait In Transcriptomics,metabolomics And N-migration Of Alternanthera Philoxeroides In Different Habitats

Alternanthera philoxeroides is a perennial,vicious and weedy weed that has been severely invaded in south of China.It has extremely strong asexual reproduction and environmental adaption.A.philoxeroides can invade terrestrial,amphibious or aquatic habitats,and also could form a single dominant community in new habitats,destroying the structure and function of the ecosystem quickly.The strategies by using transcriptomics combine with metabonomics was carried out to explore the differences in the histology of A.philoxeroides in different habitats,which is a feasible study to determine the specific molecular mechanisms of A.philoxeroides with extremely strong invasive ability and adaptability.Moreover,it has theoretical significance to reveal the ecological mechanism of the invasion of A.philoxeroides by studying the differences in the ability of nitrogen migration and utilization of A.philoxeroides in different habitats and establishing effective measures to prevent and control its invasion scientifically.In this study,the typical sampling area of A.philoxeroides was selected.Through the indoor differential culture experiments,the major differential genes of transcriptomics and metabolomics in different habitats of A.philoxeroides were analyzed.At the same time,¹⁵N isotope technology was used to measure nitrogen.In addition,the migration and utilization of hormones have been assessed for the selection trend of optimum habitats for A.philoxeroides.The result is as follows:（1）Compared to the different samples of A.philoxeroides in two different habitats,the major differentially expressed genes（DEGs）were concentrated,including 3574 DEGs in metabolic processes,3230 DEGs in cell processes,and 3041 DEGs in molecular linkages;The most obvious DEGs were enriched in photosynthetic-antennary proteins metabolic pathways（37）,metabolic pathways（1078）,photosynthesis（52）and phytohormonal signaling pathways（216）,which accounted for 0.92%,26.88%,1.3%and 5.39%of the total differentially expressed genes respectively.The metabolic pathways associated with photosynthesis and phytohormones signaling were the most significantly different in enrichment annotations,and may be the key molecular mechanisms affecting the adaptation of A.philoxeroides to different habitats.（2）The difference analysis of metabolites of A.philoxeroides in different habitats showed that there were 50.21%up-regulation and 49.79%down-regulation differential metabolites for the neg-mode of the terrestrial type compared to aquatic type of A.philoxeroides.While 46.33%up-regulation and53.67%down-regulation differential metabolites for the pos-mode.The most strong neg-mode types by cluster analysis were including phosphates,lysine subunits,leucine subunits,and linoleic acid-based substances in terrestrial-type compared to aquatic-type of A.philoxeroide.While the most intensity was classified in pos-mode type as follows alcohol subunits,aromatic esters,aldehydes,and phenolic groups;the main differential metabolites for neg-mode types with scores above 57 included linolenic acid（57.5）,hydroxyethyl lysine（57.3）and Frangulin A（57.2）or so on.The major differential metabolites for pos-mode types with scores above 57 included 4-citronellol and 4-hydroxycinnamic alcohol（57.9）,allyl cyclohexylpropionate（57.8）and 4-vinylguaiacol（57.8）or so on,which may be mainly involved in phenylpropanoid biosynthesis,nitrogen migration,endogenous hormone regulation and pyrimidine metabolism in A.philoxeroides.（3）In this study,to further reveal the main survival strategies of A.philoxeroides in different habitats,we tried to explore the difference in the phenotypic plasticity and nitrogen migration amount of A.philoxeroides in three different habitats including terrestrial,amphibious and aquatic environment.The results showed that there were significant differences in biomass and nitrogen migration amount in different organs of A.philoxeroides in different habitats.Importantly,nitrogen migration amount was significant difference（P<0.05）,which were all reflected amphibious>quatic>terrestrial in three different treatments.The average growth rate of amphibious habitat was 23.32%higher than quatic and 54.49%higher than terrestrial,respectively.The total biomass of A.philoxeroides was highest in amphibious habitat but lowest in terrestrial habitat,respectively.The distribution of biomass underground part showed a significant negative correlation with water content in different habitats,which was terrestrial>amphibious>aquatic.The distribution of average biomass in stem was 15.57%higher than that in leaf.In different habitats,the trend for plant height and internodes length of A.philoxeroides were reflected amphibious>aquatic>terrestrial.