| Oenanthe javanica(BI.)DC.is a perennial aquatic plant with medicinal value,belonging to Apiaceae,and rich in protein,dietary fiber,vitamins and minerals.In addition,O.javanica has strong adaptability to different environments.At present,research on O.javanica mainly focuses on the exploration of cultivation methods and pharmacological properties,lacks research on molecular levels such as genes and miRNAs.With the rapid development of high-throughput sequencing technology,large-scale sequencing methods such as genome,transcriptome,small RNA,degradome sequencing and expression profile have been widely applied to the study of genetic information and biomass of vegetable crops.The main contents of this study are as follows:1.The genome of O.javanica was sequenced on the HiSeq 2000 sequencing platform to construct a O.javanica genome database.After assembly,the genome size was 1.28 Gb,and 42,270 genes were predicted,of which 93.92%genes have functional annotations.Evolutionary analysis with other species shows that O.javanica and carrot have evolved the most recently.Analysis of gene family expansion/contraction revealed that 25 gene families of O.javanica had been expanded.2.The expression stability of reference genes under abiotic stress(cold,heat,salt,drought)and hormone treatment(gibberellin,salicylic acid,methyl jasmonate,abscisic acid)was compared.Appropriate reference genes were selected for each treatment.For the analysis by group:ACT7 and PP2A were selected as the most suitable genes under abiotic stress;PP2A and SAND were selected as the most suitable genes under hormone treatment.Although PP2A is the most stable gene over all samples,it is not the most stable reference gene under any specific condition.At last,the salt stress related gene M6PR was used to verify the selection of the reference gene under salt stress.3.Identify miRNAs and their target genes of O.javanica.Select 10 miRNAs and their target genes,and analyze their expression correlation under heat,cold,drought and salt stress by qPCR.It was found that Oja-miR49 inhibited the expression of oja-16563 gene by mRNA degradation.Oja-miR37 inhibited the expression of oja-36045 gene involved in flower development through translation inhibition.4.We cloned the Lhcbl genes of O.javanica and celery,and analyzed their sequences.The photosynthesis and Lhcbl gene expression under heat,cold,drought and salt stress were detected.The Lhcbl gene of O.javanica was mainly down-regulated by stress,while the Lhcbl genes of three celery varieties were mainly up-regulated by stress.The photosynthesis of celery was affected by stress,while the photosynthesis of O.javanica did not change obviously,which shows the ability to adapt to the environment.The alignments identity of the four Lhcbl genes nucleotide sequences were very high.But the gene expression pattern and photosynthesis were very different.Like other research,we deduced that single nucleotide polymorphisms of Lhcb1 could significantly affect plant traits.5.Observing the difference in morphological structure and molecular level of O.javanica under different water conditions,it was found that O.javanica had obvious response to water stress.Water deficit O.javanica showed response to water stress with obvious changes,including chlorophyll accumulation,anthocyanin production increase,more fibrous root,delayed branch development,xylem's fast grown,and starch grains rise.In addition,the genes in ribosome pathway and the LHCP genes in photosynthesis pathway were mostly down-regulated by water deficit.Differential expression analysis and functional annotation indicated that the water lacked O.javanica respond to water stress by regulating the expression of diverse miRNAs and genes.In response to water stress,Oja15472 was up-regulated by miR408 decreasing;Oja47040 was regulated by miR171,and should be related to chlorophyll accumulation and branch development. |
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