背景:木材是由维管形成层产生的次生木质部。维管形成层的活动主要包括形成层的增殖和通过次生生长形成的维管组织,从而向内产生新的次生韧皮部和向外产生次生木质部,并导致连续的树木增厚和木材形成。木材形成是一个复杂的生物过程,受到多个基因的严格调控。因此,对不同树龄的维管形成层进行分子水平的研究,可以鉴定出参与木材形成的关键基因和相关基因,并进一步解释木材形成的分子调控机制。
结果:在本研究中,RNA-Seq和Pac-BioIso-Seq用于分析尾叶桉树×桉树的基因表达变化(E。urograndis)四个不同年龄的维管形成层。鉴定了总共59,770个非冗余转录本和1892个差异表达基因(DEGs)。DEGs的表达趋势与细胞分裂和分化有关,细胞壁生物合成,植物激素,并对转录因子进行了分析。DEG编码扩展,kinesin,环素,PAL,GRP9,KNOX,C2C2-dof,REV,等。,在三岁的时候在乌鲁格蒂大肠杆菌中表达很高,对生长发育产生积极影响。此外,一些基因家族成员,例如NAC,MYB,HD-ZIPIII,RPK,和RAP,由于其复杂的转录网络和功能冗余,在木材形成中发挥不同的调节作用。
结论:这些候选基因是进一步研究木材形成的潜在资源,特别是在快速生长和适应性强的桉树中。该结果也可以作为进一步研究的基础,以阐明木材形成的分子机制。
BACKGROUND: Wood is a secondary xylem generated by vascular
cambium. Vascular
cambium activities mainly include
cambium proliferation and vascular tissue formation through secondary growth, thereby producing new secondary phloem inward and secondary xylem outward and leading to continuous tree thickening and wood formation. Wood formation is a complex biological process, which is strictly regulated by multiple genes. Therefore, molecular level research on the vascular
cambium of different tree ages can lead to the identification of both key and related genes involved in wood formation and further explain the molecular regulation mechanism of wood formation.
RESULTS: In the present study, RNA-Seq and Pac-Bio Iso-Seq were used for profiling gene expression changes in Eucalyptus urophylla × Eucalyptus grandis (E. urograndis) vascular
cambium at four different ages. A total of 59,770 non-redundant transcripts and 1892 differentially expressed genes (DEGs) were identified. The expression trends of the DEGs related to cell division and differentiation, cell wall biosynthesis, phytohormone, and transcription factors were analyzed. The DEGs encoding expansin, kinesin, cycline, PAL, GRP9, KNOX, C2C2-dof, REV, etc., were highly expressed in E. urograndis at three years old, leading to positive effects on growth and development. Moreover, some gene family members, such as NAC, MYB, HD-ZIP III, RPK, and RAP, play different regulatory roles in wood formation because of their sophisticated transcriptional network and function redundantly.
CONCLUSIONS: These candidate genes are a potential resource to further study wood formation, especially in fast-growing and adaptable eucalyptus. The results may also serve as a basis for further research to unravel the molecular mechanism underlying wood formation.