Hormone Distribution and Transcriptome Profiles in Bamboo Shoots Provide Insights on Bamboo Stem Emergence and Growth

Liu

et al. 2018

IJMS

Moso bamboo (Phyllostachys edulis) is one of the most important bamboo species in China and the third most important plant species for timber production. However, the dwarf variant of moso bamboo, P. edulis f. tubaeformis (shengyin bamboo), which has shortened internodes, is not well studied. We used anatomical, hormonal, and transcriptomic approaches to study internode shortening and shoot growth in dwarf shengyin and wild moso bamboo. Phenotypic and anatomical observations showed that dwarfing in shengyin bamboo is due to reduced internode length, and the culm fibers in shengyin bamboo are significantly shorter and thicker than in wild moso bamboo. We measured the levels of endogenous hormones in the internodes and found that shengyin bamboo had lower levels of four hormones while two others were higher in wild moso bamboo. Comparative transcriptome analyses revealed a potential regulating mechanism for internode length involving genes for cell wall loosening-related enzymes and the cellulose and lignin biosynthesis pathways. Genes involved in hormone biosynthesis and signal transduction, especially those that showed significant differential expression in the internodes between shengyin and wild moso bamboo, may be important in determining the shortened internode phenotype. A hypothesis involving possible cross-talk between phytohormone signaling cues and cell wall expansion leading to dwarfism in shengyin bamboo is proposed. The results presented here provide a comprehensive exploration of the biological mechanisms that determine internode shortening in moso bamboo.

Section: Introductionmentioning

confidence: 99%

Comparative Analyses of Anatomical Structure, Phytohormone Levels, and Gene Expression Profiles Reveal Potential Dwarfing Mechanisms in Shengyin Bamboo (Phyllostachys edulis f. tubaeformis)

Liu

et al. 2018

IJMS

“…Moreover, bamboo species often have flowering intervals from several to more than a hundred years, which is another characteristic feature of the sexual reproduction of bamboo species. To elucidate gene regulatory networks involved in these biological phenomena observed in bamboo species, several studies have utilized transcriptome analyses, and identified spatiotemporal expressions of genes explored across different tissues and developmental stages 6 – 9 , which improved the understanding of the molecular mechanisms underlying the development and growth in bamboo. However, these analyses provided little information at the cellular level, and did not identify the molecular mechanisms of cellular differentiation associated with its highly-lignified culm formation.…”

Section: Introductionmentioning

confidence: 99%

Transcriptional alterations during proliferation and lignification in Phyllostachys nigra cells

Ogita

Nomura

Kato

et al. 2018

Sci Rep

Highly-lignified culms of bamboo show distinctive anatomical and mechanical properties compared with the culms of other grass species. A cell culture system for Phyllostachys nigra has enabled investigating the alterations in cellular states associated with secondary cell wall formation during its proliferation and lignification in woody bamboos. To reveal transcriptional changes related to lignification in bamboo, we analyzed transcriptome in P. nigra cells treated with the synthetic auxin 2,4-dichlorophenoxyacetic acid (2,4-D) and the synthetic cytokinin benzylaminopurine (BA) by RNA-seq analysis. We found that some genes putatively involved in cell wall biogenesis and cell division were up-regulated in response to the 2,4-D treatment, and the induction of lignification by the BA treatment was correlated with up-regulation of genes involved in the shikimate pathway. We also found that genes encoding MYB transcription factors (TFs) show correlated expression patterns with those encoding cinnamyl alcohol dehydrogenase (CAD), suggesting that MYB TFs presumably regulate secondary cell wall formation in the bamboo cells. These findings suggest that cytokinin signaling may regulate lignification in P. nigra cells through coordinated transcriptional regulation and metabolic alterations. Our results have also produced a useful resource for better understanding of secondary cell wall formation in bamboo plants.

“…Overexpression of rice OsIAA1 , OsIAA3 , and OsIAA4 also revealed that they are involved in root, stem, and leaf architecture [ 45 ]. Very recent reports suggest that auxin signaling genes play a central role in shoot growth in woody bamboo [ 26 , 43 , 46 ]. In our study, gene families participating in auxin synthesis and signal transduction were obtained from the transcriptomes of two types of D. sinicus .…”

Section: Discussionmentioning

confidence: 99%

“…Our transcriptomic data revealed differences in the expression of lignin synthesis-related genes during shoot development. Therefore, lignin synthesis probably facilitates the construction of structural components during bamboo culm development, including culm elongation [ 46 , 52 , 53 ]. In this study, 16 annotated enzymes involved in the biosynthesis of monolignols, including H-, G-, and S-type monolignols, played roles in the formation and development of the bamboo [ 38 ].…”

Section: Discussionmentioning

confidence: 99%

Comparative Transcriptome Analysis Reveals Hormone Signaling Genes Involved in the Launch of Culm-Shape Differentiation in Dendrocalamus sinicus

Chen

Guo

Cui

et al. 2017

Genes

Dendrocalamus sinicus is a sympodial bamboo species endemic to Yunnan Province, China, and is the strongest bamboo species in the world. However, there is substantial variation in the basal culm shape, i.e., straight culm (SC) and bent culm (BC), among different D. sinicus as a result of genetic and growth factors. This study performed a comparative transcriptomic analysis of bamboo shoots of two variants at the early, mid-, and late shoot-development stages to examine the molecular basis of this variation. In total, 98,479 unigenes were annotated, of which 13,495 were differentially expressed in pairwise comparisons of the six libraries. More differentially expressed genes (DEGs) were involved in SC than in BC culm development. The DEGs between BC and SC were assigned to 108 metabolic pathways. The 1064 DEGs in early development might mainly control the launch of culm-shape differentiation. Sixty genes encoding components of hormone signaling pathways were differentially expressed between BC5 and SC5, indicating complex hormonal regulation of culm differentiation. The AUX/IAA, ARF, PP2C, SnRK2, and ABF genes involved in auxin and abscisic acid signaling played key roles. These results help us to understand the molecular mechanism of culm variation and other aspects of culm development in D. sinicus.