Transcriptomic Profiling of Cryptomeria fortunei Hooibrenk Vascular Cambium Identifies Candidate Genes Involved in Phenylpropanoid Metabolism

Abstract

Cryptomeria fortunei Hooibrenk (Chinese cedar) is a coniferous tree from southern China that has an important function in landscaping and timber production. Lignin is one of the key components of secondary cell walls, which have a crucial role in conducting water and providing mechanical support for the upward growth of plants. It is mainly biosynthesized via the phenylpropanoid metabolic pathway, of which the molecular mechanism remains so far unresolved in C. fortunei. In order to obtain further insight into this pathway, we performed transcriptome sequencing of the C. fortunei cambial zone at 5 successive growth stages. We generated 78,673 unigenes from transcriptome data, of which 45,214 (57.47%) were successfully annotated in the non-redundant protein database (NR). A total of 8975 unigenes were identified to be significantly differentially expressed between Sample_B and Sample_A after analyzing their expression profiles. Of the differentially expressed genes (DEGs), 6817 (75.96%) and 2158 (24.04%) were up- and down-regulated, respectively. 83 DEGs were involved in phenylpropanoid metabolism, 37 DEGs that encoded v-Myb avian myeloblastosis viral oncogene homolog (MYB) transcription factor (TF), and many candidates that encoded lignin synthesizing enzymes. These findings contribute to understanding the expression pattern of C. fortunei cambial zone transcriptome. Furthermore, our results provide additional insight towards understanding the molecular mechanisms of wood formation in C. fortunei.

Transcriptome and microRNA Sequencing Identified miRNAs and Target Genes in Different Developmental Stages of the Vascular Cambium in Cryptomeria fortunei Hooibrenk

“…The families with the most abundant expression were miR396, miR159, and miR319, while the families with the least abundant expression were miR946, miR399, and miR529. miR159 ( Millar et al, 2019 ), miR160 ( Ding et al, 2017 ; Wójcik et al, 2017 ), and miR166 ( Yan et al, 2016 ; Yang et al, 2020b ) are known to be mainly involved in hormone signal transduction, while miR166 ( Zhou et al, 2015 ), miR167 ( Cai et al, 2019 ), and miR396 ( Debernardi et al, 2014 ) are mainly involved in growth and development, and miR394 ( Song et al, 2013 ), miR156 ( Chen et al, 2020b ), and miR395 ( Ai et al, 2016 ) are mainly involved in stress response regulation.…”

“…Two plant hormones strongly involved in plant development and dormancy are ABA and GA. During phases of vigorous plant growth, the level of ABA decreases, and the level of GA increases ( Liu et al, 2011 ). miR166 is involved in ABA signal transduction in plants and expressed at low levels during somatic embryo maturation ( Yan et al, 2016 ; Yang et al, 2020b ). These findings are consistent with the conclusion that ABA is a key factor for somatic embryo maturation, as low miR166 levels would lead to high levels of ABA.…”

“…As previously described ( Yang et al, 2020a ), we acquired samples from C. fortunei trees aged approximately 60years with no obvious presence of insect pests or disease from the arboretum of Nanjing Forestry University, Nanjing City, Jiangsu Province, China (32°08′20.2″N,118°81′85.9″E). With a slight modification to Soile’s method ( Soile et al, 2018 ), the vascular cambium tissue under the bark of the trunk was scraped with a blade immediately frozen in liquid nitrogen and then stored at −80°C.…”

Integrated transcriptome and endogenous hormone analysis provides new insights into callus proliferation in Osmanthus fragrans

“…Recently developed bioinformatics and large-scale sequencing platforms have reduced sequencing costs and cycle times, and are widely used in transcriptome studies 17 . Transcriptome sequencing technologies provide a range of information, including gene domain functional annotation, variable cleavage, transcriptional sequencing, differential gene expression analysis, and gene function classification 18 .…”

Genetics and Improvement of Forest Trees

“…Kurita et al [13] examine genes promoting male strobilus formation after gibberellin treatment in C. japonica. Yang et al [14] reveal candidate genes related to wood formation in C. fortunei. Cao et al [15] study genes controlling wood properties in Cunninghamia lanceolate (Lamb.)…”