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Article|30 Nov 2018|OPEN
Molecular breeding of water lily: engineering cold stress tolerance into tropical water lily
Cuiwei Yu1,2,3, Guirong Qiao1,3, Wenmin Qiu1,3, Dongbei Yu2, Shirong Zhou2, Yan Shen2, Guanchun Yu2, Jing Jiang1,3, Xiaojiao Han1,3, Mingying Liu1,3, Liangsheng Zhang4, Fei Chen4,, Yuchu Chen2, & Renying Zhuo1,3,
1State Key Laboratory of Tree Genetics and Breeding, Chinese Academy of Forestry, 100091 Beijing, China
2Zhejiang Humanities Landscape Co., Ltd., Hangzhou Tianjing Aquatic Botanical Garden, 310000 Hangzhou, Zhejiang, China
3Key Laboratory of Tree Breeding of Zhejiang Province, The Research Institute of Subtropical forestry, Chinese Academy of Forestry, 311400 Hangzhou, Zhejiang, China
4State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, Key Laboratory of Ministry of Education for Genetics, Breeding and Multiple Utilization of Crops, Fujian Provincial Key Laboratory of Haixia Applied Plant Systems Biology, Fujian Agriculture and Forestry University, 350002 Fuzhou, China

Horticulture Research 5,
Article number: 73 (2018)
doi: 10.1038/hortres.2018.73
Views: 711

Received: 17 Oct 2017
Revised: 26 Aug 2018
Accepted: 30 Aug 2018
Published online: 30 Nov 2018

Abstract

Water lilies (order Nymphaeales) are rich in both economic and cultural values. They grow into aquatic herbs, and are divided into two ecological types: tropical and hardy. Although tropical water lilies have more ornamental and medicinal values compared to the hardy water lily, the study and utilization of tropical water lilies in both landscaping and pharmaceutical use is greatly hindered due to their limited planting area. Tropical water lilies cannot survive the winter in areas beyond 24.3°N latitude. Here, the transgenic pipeline through the pollen-tube pathway was generated for water lily for the first time. To improve cold stress tolerance of tropical water lilies, a gene encoding choline oxidase (CodA) driven by a cold stress-inducible promoter was transformed into a tropical water lily through the pollen-tube transformation. Six independent transgenic lines were tested for survival rate during two winter seasons from 2015 to 2017 in Hangzhou (30.3°N latitude). PCR and southern blot detection revealed that the CodA gene had been integrated into the genome. Reverse transcription PCR showed that CodA gene was induced after cold stress treatment, and further quantitative real-time PCR revealed different expressions among six 4 lines and line 3 had the highest expression. Multiple physiological experiments showed that after cold stress treatment, both the conductivity and malondialdehyde (MDA) levels from transgenic plants were significantly lower than those of non-transgenic plants, whereas the content of betaine and the activity of superoxide dismutase, catalase, and peroxidase were higher than those from non-transgenic plants. These results suggest that expression of exogenous CodA gene significantly improved the cold stress tolerance of tropical water lilies through a wide range of physiological alterations. Our results currently expanded a six-latitude cultivating area of the tropical water lilies. These results not only illuminate the bright future for water lily breeding but will also facilitate the functional genomic studies.