Kang Dongru, Li Zhongai, Li Mangmang, Li Jie, Liu Yanhua, Ai Penghui, Ding Hongxu, Zhu Yi, Wang Ying and Wang Zicheng
Plant Germplasm Resources and Genetic Laboratory, Kaifeng Key Laboratory of Chrysanthemum Biology, School of Life Sciences, Henan University, Kaifeng, Henan, China

SUMMARY DNA methylation plays an important role in plant growth and development. The purpose of this study was to observe the expression of DNA methylation related genes in Chrysanthemum × morifolium. Homologous genes related to DNA methylation in chrysanthemum were cloned, and obtained 1,509-bp for CmCMT, 1,470-bp for CmDRM and 608-bp for CmDME. The C. morifolium cultivar ‘Nannonghongxiu’ was exposed to short-day (SD) conditions, and the expression of DNA methyltransferase and demethylase genes in flowering plants was analyzed by quantitative real-time polymerase chain reaction. At flowering stage, CmFT expression level exhibited an increasing trend while CmMET1 and CmCMT3 showed a decreasing trend; the intensity of decrease was greater in SD-treated plants compared to control plants in the same stage. The expression of CmDRM2 was up-regulated in the flowering stage. The expression level of CmDRM2 was lower in control plants as compared to SD-treated plants in the first three growth stages. However, the CmDRM2 expression level in the control plants was at peak during full bloom stage as well as higher than SD-treated plants. The highest CmDME expression level was observed during full bloom stage in both types, however, control plants showed higher level in comparison with the plants exposed to SD conditions. The expression levels of the DNA methyltransferase and demethylase genes undergo dynamic changes during the transition from vegetative growth to reproductive growth (flowering induction stage) and flower development, which seems to influence DNA methylation changes in the leaves. Keywords Chrysanthemum × morifolium, gene clone, DNA methylation, vegetative growth, reproductive growth

Significance of this study What is already known on this subject? It is well known that DNA methylation plays an important role in the growth and development of plants, but the specific mechanism in the induction of flowering in Chrysanthemums is still unclear. What are the new findings? The expression level of the DNA methyltransferase and demethylase genes undergo dynamic changes during the transition from vegetative growth to reproductive growth. What is the expected impact on horticulture? The study on the expression of DNA methylation-related genes not only provides genetic resources for the subsequent regulation of flowering period in Chrysanthemums, but also provides a basis for the subsequent studies on related mechanisms.

E-mail: wzc@henu.edu.cn  

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Received: 28 May 2020 | Accepted: 14 October 2020 | Published: 3 May 2021 | Available online: 3 May 2021