Transcriptome analysis reveals gene expression involved in adventitious roots formation regulated by ethylene in lotus

Lotus is a member of the Nymphaeaceae family, which contains two species: N. nucifera and N. Lutea. Lotus (Nelumbo nucifera Gaertn.) has three phenotypes including rhizome lotus, seed lotus and flower lotus, and it is wildly grown in Asia, especially in China and India. In China, the main cultivated region of lotus is distributed in Hubei, Jiangsu, Fujian, Zhejiang and Guangxi provinces, among which, Hubei and Jiangsu province have the largest planting area than other province in lotus root product due to suitable climate. Lotus root is believed as an indispensable aquatic herbaceous vegetable in south China due to its richness in nutrition. The germ, stamens, and stems of lotus root are also important ingredients in traditional medicine. To date, China has been the world leader in lotus production for multiple purposes. For traditional breeding of lotus, mutation through hybridization and the fixation of variation by asexual propagation are the main methods to create new varieties. As this results in a relatively under-developed principle root, ARs play an important role in water and nutrient uptake in lotus seedling.