State Key Laboratory of Subtropical Silviculture, Zhejiang A & F University, 666 Wusu Street, Hangzhou 311300, China.
College of Life Sciences, Qingdao University, 308 Ningxia Road, Qingdao 266071, China.
Tree Physiol. 2020 Aug 29;40(9):1217-1231. doi: 10.1093/treephys/tpaa053.
Acid invertases (INVs) play a pivotal role in both vegetative and reproductive growth of plants. However, their possible functions in fast-growing plants such as bamboo are largely unknown. Here, we report the molecular characterization of acid INVs in Phyllostachys heterocycla cv. pubescens, a fast-growing bamboo species commercially grown worldwide. Nine acid INVs (PhINVs), including seven cell wall INVs (PhCWINV1, PhCWINV2, PhCWINV3, PhCWINV4, PhCWINV5, PhCWINV6 and PhCWINV7) and two vacuolar INVs (PhVINV11 and PhVINV12) were isolated. Bioinformatic analyses demonstrated that they all share high amino acid identity with other INVs from different plant species and contain the motifs typically conserved in acid INV. Enzyme activity assays revealed a significantly higher INV activity in the fast-growing tissues, such as the elongating internodes of stems. Detailed quantitative reverse-transcription PCR analyses showed various expression patterns of PhINVs at different developmental stages of the elongating stems. With the exception of PhCWINV6, all PhINVs were ubiquitously expressed in a developmental-specific manner. Further studies in Arabidopsis exhibited that constitutive expression of PhCWINV1, PhCWINV4 or PhCWINV7 increased the biomass production of transgenic plants, as indicated by augmented plant heights and shoot dry weights than the wild-type plants. All these results suggest that acid INVs play a crucial role in the internode elongation of P. heterocycla cv. pubescens and would provide valuable information for the dissection of their exact biological functions in the fast growth of bamboo.
酸性转化酶（INVs）在植物的营养生长和生殖生长中都起着关键作用。然而，它们在像竹子这样的快速生长植物中的可能功能在很大程度上是未知的。在这里，我们报道了毛竹（Phyllostachys heterocycla cv. pubescens）中酸性 INV 的分子特征，毛竹是一种在世界范围内广泛商业化种植的快速生长的竹种。我们分离了 9 个酸性 INV（PhINVs），包括 7 个细胞壁 INV（PhCWINV1、PhCWINV2、PhCWINV3、PhCWINV4、PhCWINV5、PhCWINV6 和 PhCWINV7）和 2 个液泡 INV（PhVINV11 和 PhVINV12）。生物信息学分析表明，它们与来自不同植物物种的其他 INV 具有很高的氨基酸同一性，并含有酸性 INV 中典型的保守基序。酶活性测定显示，在快速生长的组织中，如茎的伸长节间，INV 活性显著较高。详细的定量反转录 PCR 分析显示，在伸长茎的不同发育阶段，PhINVs 的表达模式各不相同。除了 PhCWINV6 之外，所有 PhINVs 都以发育特异性的方式广泛表达。在拟南芥中的进一步研究表明，PhCWINV1、PhCWINV4 或 PhCWINV7 的组成型表达增加了转基因植物的生物量产量，表现为比野生型植物更高的株高和茎干重量。所有这些结果表明，酸性 INV 在毛竹 cv. pubescens 的节间伸长中起着至关重要的作用，并为解析它们在竹子快速生长中的确切生物学功能提供了有价值的信息。
