| Spathiphyllum,belonging to the family Araceae,is a kind of perennial herb,which has ornamental and economic value.However,Leaf is the main ornamental part of Spathiphyllum,but there is little known on morphogenesis and growth regulation.Therefore,Studying the growth rhythm of Spathiphyllum leaves can provide a basis for growth regulation and production technology improvement.In this study,the leaf width,leaf length,leaf area,leaf vein number,leaf tip angles,leaf full length and leaf SPAD of three cultivar of S.‘Mojo’,S.‘Sensation’and S.‘Queen’with different shape were measured during the leaf growth stages and data were statistically analyzed for a quantitative leaf growth and fitting to the logistic equation as leaf growth models.Illumina Nova Seq6000 high-throughput sequencing platform was used to sequence the leaves of S.‘Mojo’of Pre-growth stage(S0),Fast-growth stage(S1)and Post-growth stage(S2)and the Unigenes sequences acquired were compared to Nr,KEGG and GO and other databases.Mostly enriched metabolism pathways and the main biological event of the leaf growth were discussed by using plant TFDB,Mapman,STRING and other bioinformatics software.According to the DEGS expression level and interaction network of transcription factors,leaf growth and morphology-related genes were found.A funnel-shaped plot presented a two-dimensional dynamic pattern of full leaf length and leaf width change greatly over time.The full leaf length,leaf width,leaf length and leaf area of Spathiphyllum changed greatly with time and were the key growth characters.Fitting degree R~2 of four Logistic growth equations for those characters were above 0.97 and the coefficients between the measured and theoretical values were all above 0.99,which means the Logistic equations were suitable for fitting the growth of the Spathiphyllum leaves.The observation of Spathiphyllum leaves growth rhythm showed that the full leaf length,leaf length,leaf width,leaf length and leaf area were in accordance with the growth curve of“slow-fast-slow”of“S”pattern.Pre-growth stage,Fast-growth stage and Post-growth stage were deduced for Spathiphyllum leaf growth through the derivation of the Logistic growth equation combining with the leaf morphological changes.There were significant morphological differences in leaf characters among 3 cultivars of Spathiphyllum.The leaf length,leaf length,leaf thickness and SPAD value were the differences in leaf morphological changes among cultivars.The coefficient variation distribution was 18.07%-88.85%and the Shannon genetic diversity index H’was 2.94-3.28 for 8 leaf characters of 3 cultivars,indicating the genetic diversity in Spathiphyllum.Based on the assembling result of Illumina Nova Seq6000 transcriptome sequencing,a total of 27201 unigenes with annotation information were obtained after comparison analysis of the functional databases,54910 transcripts were classified as CDS and 11571 simple sequence repeats(SSRs)markers were detected.Under the condition of FPKM≥1,|FC|>2and FDR<0.01,the pathways with significant enrichment expressed genes were photosynthesis,Photosynthesis antenna protein,Carbon fixation in photosynthesis,Carotenoid biosynthesis.35 Photosynthesis pathway-related genes,including 7 Antenna protein genes,23 Carbon metabolism-related genes,7 Chlorophyll synthesis-related genes,10 Cell wall activity-related genes,13 Plant hormone signal transduction-related genes and56 Transcription factors through the gene expression differences in different stages of the leaves of Spathiphyllum were found.Sp XTH22 was the key gene for leaf growth of Spathiphyllum,which had the highest up-regulation range with time among all the analyzed genes.Gene interaction network analysis of transcription factor revealed that 3 networks were formed by 27 transcription factors which 7 key genes Sp TCP4,Sp TCP20,Sp BLH2,Sp BLH4,Sp GAI1,Sp MYB91,Sp CUC2 relative to leaf growth were screened out from that interaction each other to control the growth and morphology development of Spathiphyllum leaves. |
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