Based On Transcriptomics Analysis The Petalization Mechanism Of Stamens In Paeonia Lactiflora Pall. "Zhongjiang"

Paeonia lactiflora is a perennial herb with significant medicinal and ornamental value.P.lactiflora “CBS-B” is a new variety of high-quality P.lactiflora primarily promoted in the Sichuan Province.Although its stamens are all petaloidy and have high ornamental value,its inability to fruit naturally due to the lack of stamens poses a challenge.In this study,we aimed to explore the causes of stamen petalization by observing the flower bud development process and stamen petalization characteristics of P.lactiflora “CBS-B” and comparing it with P.lactiflora “Bozhou”.According to the results of phenotypic observation,to identify candidate genes that regulate stamen petalization,we selected materials of low petaloid stamens,moderate petaloid stamens,high petaloid stamens and normal petals from P.lactiflora “CBS-B” and employed second-generation high-throughput sequencing technology.The main results are as follows:1.The results of phenotypic observation revealed that P.lactiflora “CBS-B” stamens are homologous into petals,the double petals originated from stamens,and the flower type was Tuogui.Petalization began during stamen primordium differentiation,with stamens in the center of the flower tray developing faster than those at the edge.The direction of stamen petalization was centrifugal,resulting in a variety of petals.2.The high-throughput sequencing technology was used to compare and analyze the RNA-Seq of flower organ samples of P.lactiflora “CBS-B”.A total of 12 c DNA libraries of stamens and petals with different degrees of petalization were constructed,resulting in a total of 71.53 Gb effective data and 77 194 unigenes.Functional annotation in NR,PFAM,GO,Swiss Prot,NT,KO,and KOG databases revealed that 53.65% of the unigenes(41 422)were annotated.Differential expression analysis identified 4 358 DEGs between moderate petal stamens and low petal stamens,high petal stamens and low petal stamens,and normal petals and low petal stamens,of which 515 genes were up-regulated and 3 839 genes were down-regulated.The common differential genes were mainly enriched in starch and sugar metabolism,phenylpropanoid biosynthesis,plant hormone signal transduction,and zeatin biosynthesis.3.Our transcriptome difference analysis revealed that glucose metabolism,hormones and transcription factors significantly regulated the petalody of P.lactiflora “CBS-B”.The glucose metabolism pathway included genes such as GLU1,BGLU13,BGLU18,BGLU12,At2g44540,TPS9,PME21,PME58,PME28,PME13 and PME21.Genes such as ALDH,IPT,met K,ARR-B,GID1 and KAO were closely related to the formation of stamen petalization in P.lactiflora “CBS-B”.Transcription factors such as AGAMOUS,AGL15,LHCA4,SOC1,MYB108,MYB102,MYB2 and others played a crucial regulatory role in the stamen petalization of P.lactiflora “CBS-B”.