title: Biochemical and molecular changes associated with heteroxylan biosynthesis in Neolamarckia cadamba (Rubiaceae) during xylogenesis.
abstract: Wood, derived from plant secondary growth, is a commercially important material. Both cellulose and lignin assembly have been well studied during wood formation (xylogenesis), but heteroxylan biosynthesis is less well defined. Elucidation of the heteroxylan biosynthetic pathway is crucial to understand the mechanism of wood formation. Here, we use Neolamarckia cadamba, a fast-growing tropical tree, as a sample to analyze heteroxylan formation at the biochemical and molecular levels during wood formation. Analysis of the non-cellulosic polysaccharides isolated from N. cadamba stems shows that heteroxylans dominate non-cellulosic polysaccharides and increase with xylogenesis. Microsomes isolated from stems of 1-year-old N. cadamba exhibited UDP-Xyl synthase and xylosyltransferase activities with the highest activity present in the middle and basal stem regions. To further understand the genetic basis of heteroxylan synthesis, RNA sequencing (RNA-seq) was used to generate transcriptomes of N. cadamba during xylogenesis. The RNA-seq results showed that genes related to heteroxylan synthesis had higher expression levels in the middle and basal part of the stem compared to the apical part. Our results describe the heteroxylan distribution and heteroxylan synthesis trait in N. cadamba and give a new example for understanding the mechanism of heteroxylan synthesis in tropical tree species in future.
authors.affiliation: Guangdong Key Laboratory for Innovative Development and Utilization of Forest Plant Germplasm, South China Agricultural University, Guangzhou China ; State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, Guangzhou China.
authors.forename: Xianhai
authors.initials: X
authors.lastname: Zhao
authors.affiliation: Guangdong Key Laboratory for Innovative Development and Utilization of Forest Plant Germplasm, South China Agricultural University, Guangzhou China ; State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, Guangzhou China.
authors.forename: Kunxi
authors.initials: K
authors.lastname: Ouyang
authors.affiliation: State Key Laboratory of Tree Genetics and Breeding, Chinese Academy of Forestry, Beijing China ; Research Institute of Tropical Forestry, Chinese Academy of Forestry, Guangzhou China.
authors.forename: Siming
authors.initials: S
authors.lastname: Gan
authors.affiliation: ARC Centre of Excellence in Plant Cell Walls, School of Botany, The University of Melbourne, Parkville, VIC Australia.
authors.forename: Wei
authors.initials: W
authors.lastname: Zeng
authors.affiliation: Nurturing Station for the State Key Laboratory of Subtropical Silviculture, Zhejiang A & F University, Hangzhou China.
authors.forename: Lili
authors.initials: L
authors.lastname: Song
authors.affiliation: Guangdong Key Laboratory for Innovative Development and Utilization of Forest Plant Germplasm, South China Agricultural University, Guangzhou China ; State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, Guangzhou China.
authors.forename: Shuai
authors.initials: S
authors.lastname: Zhao
authors.affiliation: Guangdong Key Laboratory for Innovative Development and Utilization of Forest Plant Germplasm, South China Agricultural University, Guangzhou China ; State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, Guangzhou China.
authors.forename: Juncheng
authors.initials: J
authors.lastname: Li
authors.affiliation: ARC Centre of Excellence in Plant Cell Walls, School of Botany, The University of Melbourne, Parkville, VIC Australia.
authors.forename: Monika S
authors.initials: MS
authors.lastname: Doblin
authors.affiliation: ARC Centre of Excellence in Plant Cell Walls, School of Botany, The University of Melbourne, Parkville, VIC Australia ; Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Parkville, VIC Australia.
authors.forename: Antony
authors.initials: A
authors.lastname: Bacic
authors.affiliation: Guangdong Key Laboratory for Innovative Development and Utilization of Forest Plant Germplasm, South China Agricultural University, Guangzhou China ; State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, Guangzhou China.
authors.forename: Xiao-Yang
authors.initials: XY
authors.lastname: Chen
authors.affiliation: Centre for Biological Sciences, University of Southampton, Southampton UK.
authors.forename: Alan
authors.initials: A
authors.lastname: Marchant
authors.affiliation: Guangdong Key Laboratory for Innovative Development and Utilization of Forest Plant Germplasm, South China Agricultural University, Guangzhou China ; State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, Guangzhou China ; College of Forest, South China Agricultural University, Guangzhou China.
authors.forename: Xiaomei
authors.initials: X
authors.lastname: Deng
authors.affiliation: Guangdong Key Laboratory for Innovative Development and Utilization of Forest Plant Germplasm, South China Agricultural University, Guangzhou China ; State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, Guangzhou China ; College of Forest, South China Agricultural University, Guangzhou China.
authors.forename: Ai-Min
authors.initials: AM
authors.lastname: Wu
keywords: Neolamarckia cadamba (Rubiaceae); RNA-seq; XylT activity; heteroxylan; xylogenesis