Dendrobium officinale seed symbiotic germination iTRAQ

Mycorrhizal fungi colonize orchid seed and induce the germination. This so-called symbiotic germination is a critical developmental process in the lifecycle of all orchids. However, the molecular changes taking place during the orchid seed symbiotic germination still remains largely unknown. To better understand the molecular mechanism of orchid seed germination, we performed comparative transcriptomic and proteomic analysis on Chinese traditional medicinal orchid plants, Dendrobium officinale to explore protein expression change at the different developmental stages between asymbiotic and symbiotic germination and identify the key proteins regulated symbiotic germination of orchid seeds. iTRAQ analysis from 8 samples identified 2256 plant proteins, of which, 308 proteins were differentially expressed across three developmental stages within asymbiotic or symbiotic accession and 229 proteins are differentially expressed in the symbiotic germination compared to asymbiotic germination. 32 proteins are co-upregulated in both proteomic and transcriptomic level for symbiotic germination compared to asymbiotic germination. Our results revealed that symbiotic germination of D. officinale seeds probably shares the common signal pathway with asymbiotic germination during the early germination stage.

菌根真菌（Mycorrhizal fungi）定殖于兰科植物种子并诱导其萌发，这种所谓的共生萌发（symbiotic germination）是所有兰科植物生命周期中的关键发育进程。然而，兰科种子共生萌发过程中发生的分子变化目前仍鲜为人知。为深入解析兰科种子萌发的分子机制，本研究以中国传统药用兰科植物铁皮石斛（Dendrobium officinale）为材料，开展比较转录组学与蛋白质组学分析，探究非共生萌发与共生萌发在不同发育阶段的蛋白质表达变化，并筛选调控兰科种子共生萌发的关键蛋白。本研究通过对8个样本进行iTRAQ（isobaric Tags for Relative and Absolute Quantitation，同位素相对与绝对定量标签）分析，共鉴定到2256个植物蛋白；其中，在非共生萌发或共生萌发体系的三个发育阶段中，共有308个蛋白存在差异表达，而共生萌发体系相较于非共生萌发体系则有229个蛋白呈现差异表达。相较于非共生萌发，共生萌发过程中共有32个蛋白在蛋白质组与转录组水平上均呈上调表达。本研究结果表明，铁皮石斛种子的共生萌发与非共生萌发在萌发早期可能共享相同的信号通路。