Co-Innovation Center for Sustainable Forestry in Southern China, Nanjing Forestry University, Nanjing, Jiangsu 210037, China.
Bamboo Research Institute, Nanjing Forestry University, Nanjing, Jiangsu 210037, China.
Tree Physiol. 2018 Apr 1;38(4):641-654. doi: 10.1093/treephys/tpx129.
Few studies about bamboo naturally occurring mutants have been reported so far. Using an integrated anatomy, mathematics and genomics approach, we systematically characterized the cellular and molecular basis underlying the abnormal internode development of Pseudosasa japonica var. tsutsumiana, a stable variant with dwarf and swollen internodes that are caused by the compressed spiral growth and the swollen cells in the bottom part of the internode. P. japonica var. tsutsumiana is a slow-growth variant with disorderly cell division and cell growth during the fast growth stage. Comparative transcriptome analysis identified a number of genes related to cell growth that were significantly down-regulated in the variant, including those related to auxin, vesicle transport, cytoskeleton organization and cell wall modification, consistent with the thinner cell walls and lower contents of cellulose that were found in the variant, which together with the mechanic force composed by the extrusion pressure from the neighboring fast growth cells and the weight pressure above the growing cells might finally result in the radial and irregular growth of the variant cells. This study provides key candidate genes involved in the fast growth of bamboo from a 'mutant' perspective, and supports a plausible mechanism underlying the dwarf and swollen internodes of P. japonica var. tsutsumiana.
目前为止，关于天然发生的竹子突变体的研究甚少。本研究采用综合解剖学、数学和基因组学方法，系统地描述了矮小肿胀节间突变体毛竹（Pseudosasa japonica var. tsutsumiana）异常节间发育的细胞和分子基础。该突变体具有矮化和肿胀的节间，这是由螺旋压缩生长和节间下部细胞肿胀引起的。毛竹（Pseudosasa japonica var. tsutsumiana）是一个生长缓慢的突变体，在快速生长阶段有紊乱的细胞分裂和细胞生长。比较转录组分析鉴定了一些与细胞生长相关的基因，这些基因在突变体中显著下调，包括与生长素、囊泡运输、细胞骨架组织和细胞壁修饰相关的基因，这与突变体中发现的细胞壁较薄和纤维素含量较低一致，这种情况加上由相邻快速生长细胞的挤压压力和生长细胞上方的重量压力组成的机械力，可能最终导致突变体细胞的径向和不规则生长。本研究从“突变体”的角度提供了参与竹子快速生长的关键候选基因，并支持毛竹（Pseudosasa japonica var. tsutsumiana）矮化肿胀节间的可能机制。
