Li Changtao, Xuan Lingling, He Yuming, Wang Jie, Zhang Hui, Ying Yeqing, Wu Aimin, Bacic Antony, Zeng Wei, Song Lili
Sino-Australia Plant Cell Wall Research Centre, The State Key Laboratory of Subtropical Silviculture, School of Forestry and Biotechnology, Zhejiang A&F University, Lin'an, 311300, China.
Guangdong Key Laboratory for Innovative Development and Utilization of Forest Plant Germplasm, College of Forestry, South China Agricultural University, Guangzhou 510642, China.
Polymers (Basel). 2018 Dec 27;11(1):38. doi: 10.3390/polym11010038.
A bamboo shoot is the immature stem of the woody grass and a nutritious and popular vegetable in East Asia. However, it undergoes a rapid xylogenesis process right after harvest, even being stored in a cold chamber. To investigate the molecular regulation mechanisms of xylogenesis in Moso bamboo () shoots (MBSes) during cold storage, the measurement of cell wall polymers (cellulose, hemicellulose, and lignin) and related enzyme activities (phenylalanine ammonia lyase (PAL), cinnamyl alcohol dehydrogenase (CAD), peroxidase (POD), and xylan xylosyltransferase (XylT)) and transcriptomic analysis were performed during cold storage. It was noticed that cellulose and lignin contents increased, while hemicellulose content exhibited a downward trend. PAL, CAD, and POD activity presented an upward trend generally in MBS when stored at 4 °C for 16 days. XylT activity showed a descending trend during the stages of storage, but slightly increased during the 8th to 12th days after harvest at 4 °C. Transcriptomic analysis identified 72, 28, 44, and 31 functional unigenes encoding lignin, cellulose, xylan biosynthesis enzymes, and transcription factors (TFs), respectively. Many of these secondary cell wall (SCW)-related genes showed higher expression levels in the later period of cold storage. Quantitative RT-PCR analysis of the selected genes conformed to the expression pattern. Our study provides a comprehensive analysis of MBS secondary wall biosynthesis at the molecular level during the cold storage process. The results give insight into the xylogenesis process of this economically important vegetable and shed light on solving this problem of the post-harvest industry.
竹笋是木本禾本科植物未成熟的茎，是东亚地区一种营养丰富且受欢迎的蔬菜。然而，即使储存在冷藏室中，竹笋在收获后也会经历快速的木质化过程。为了研究冷藏期间毛竹（）竹笋（MBS）木质化的分子调控机制，在冷藏期间对细胞壁聚合物（纤维素、半纤维素和木质素）和相关酶活性（苯丙氨酸解氨酶（PAL）、肉桂醇脱氢酶（CAD）、过氧化物酶（POD）和木聚糖木糖基转移酶（XylT））进行了测定，并进行了转录组分析。结果发现，纤维素和木质素含量增加，而半纤维素含量呈下降趋势。在4℃储存16天期间，MBS中的PAL、CAD和POD活性总体呈上升趋势。XylT活性在储存阶段呈下降趋势，但在4℃收获后第8至12天略有增加。转录组分析分别鉴定出72、28、44和31个编码木质素、纤维素、木聚糖生物合成酶和转录因子（TFs）的功能单基因。许多这些与次生细胞壁（SCW）相关的基因在冷藏后期表现出较高的表达水平。对所选基因的定量RT-PCR分析与表达模式相符。我们的研究在分子水平上对冷藏过程中MBS次生壁生物合成进行了全面分析。研究结果为这种经济上重要的蔬菜的木质化过程提供了深入了解，并为解决采后行业的这一问题提供了思路。
