Comparative Transcriptome Analysis and Expression of Genes Associated with Polysaccharide Biosynthesis in <i>Dendrobium officinale</i> Diploid and Tetraploid Plants oleh Phu Long Pham, Thi Tuyet Cham Le, Thi Thuy Hang Vu, Thanh Tuan Nguyen, Zhi-Sheng Zhang, Rui-Zhen Zeng, Li Xie, Minh Ngoc Nguyen, Vuong Thi Huyen Trang, Tran Dang Xuan, Tran Dang Khanh