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Article|01 Aug 2018|OPEN
Loss or duplication of key regulatory genes coincides with environmental adaptation of the stomatal complex in Nymphaea colorata and Kalanchoe laxiflora
Meizhi Xu1, Fei Chen2, Shilian Qi1, Liangsheng Zhang1,2 & Shuang Wu1,
1College of Horticulture, FAFU-UCR Joint Center and Fujian Provincial Key Laboratory of Haixia Applied Plant Systems Biology, Fujian Agriculture and Forestry University, Fuzhou, China
2State 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 Agriculture and Forestry University, Fuzhou, China

Horticulture Research 5,
Article number: 18042 (2018)
doi: 10.1038/hortres.2018.42
Views: 1065

Received: 14 Jan 2018
Revised: 22 Apr 2018
Accepted: 26 Apr 2018
Published online: 01 Aug 2018

Abstract

The stomatal complex is critical for gas and water exchange between plants and the atmosphere. Originating over 400 million years ago, the structure of the stomata has evolved to facilitate the adaptation of plants to various environments. Although the molecular mechanism of stomatal development in Arabidopsis has been widely studied, the evolution of stomatal structure and its molecular regulators in different species remains to be answered. In this study, we examined stomatal development and the orthologues of Arabidopsis stomatal genes in a basal angiosperm plant, Nymphaea colorata, and a member of the eudicot CAM family, Kalanchoe laxiflora, which represent the adaptation to aquatic and drought environments, respectively. Our results showed that despite the conservation of core stomatal regulators, a number of critical genes were lost in the N. colorata genome, including EPF2, MPK6, and AP2C3 and the polarity regulators BASL and POLAR. Interestingly, this is coincident with the loss of asymmetric divisions during the stomatal development of N. colorata. In addition, we found that the guard cell in K. laxiflora is surrounded by three or four small subsidiary cells in adaxial leaf surfaces. This type of stomatal complex is formed via repeated asymmetric cell divisions and cell state transitions. This may result from the doubled or quadrupled key genes controlling stomatal development in K. laxiflora. Our results show that loss or duplication of key regulatory genes is associated with environmental adaptation of the stomatal complex.