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Title: Hormone Signaling and Alternative splicing in Moso Bamboo Shoot Growth

Jian Gao

International Centre for Bamboo and Rattan, China

Biography

Prof. Dr. Jian Gao  studied Forestry in Nanjing Forestry University, graduated as MS in 1993. She then joined the Department of Forestry in Anhui Agricultural University. She received her PhD degree in 2000 in China Academy of Forestry.  After one year postdoctoral fellowship supervised by Prof. Dr. Andrea Polle at the Institute of Forest Botany, Goettingen University, Germany. She obtained the position of Professor at the ICBR. She has published more than 40 research articles in SCI(E) journals.

Abstract

Moso bamboo is a large, woody bamboo with the highest ecological, economic and culturalvalue of all the bamboo types and accounts for up to 70% of the total area of bamboo grown. However, the spatiotemporal variation role of moso bamboo shoot during growth period is still unclear. We found that the bamboo shoot growth can be divided into three distinct periods, including winter growth, early growth and late growth based on gene expression and anatomy.

In the early growth period, lateral buds germinated from the top of the bamboo joint in the shoot tip. Intercalary meristems grew vigorously during the winter growth period and early growth period, but in the late growth period, mitosis in the intercalary meristems decreased. The expression of cell cycle-associated genes and the quantity of differentially expressed genes were higher in early growth than those in late growth, appearing to be influenced by hormonal concentrations. Gene expression analysis indicates that hormone signalling genes play key roles in shoot growth, while auxin signalling genes play a central role. In situ hybridization analyses illustrate how auxin signalling genes regulate apical dominance, meristem maintenance and lateral bud development. Our study provides a vivid picture of the dynamic changes in anatomy and gene expression during shoot growth in moso bamboo, and how hormone signalling-associated genes participate in moso bamboo shoot growth.

Alternative splicing (AS) is a key regulatory mechanism associated with proteome and transcriptome diversity. However, the prevalence of AS in the moso bamboo genome is still unclear. Transcriptome sequencing of four different tissues indicated that 36.17% of the genes in the moso bamboo genome undergo AS. The predominant type of AS found in moso bamboo was intron retention (38.70%), followed by alternative 5′ (31.86%) and 3′ (16.68%) splice sites and exon skipping (11.46%). The number of AS events in every gene was relevant to gene characteristics and gene expression. We also observed that the alternative 5′ and 3′ splice sites were significantly enriched in the fourth nucleotide downstream or upstream of the dominant splice sites. Furthermore, the frequency of AS types as well as the quantity of AS events significantly varied among different tissues. The findings of the present study