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Article|23 Mar 2022|OPEN
Heterografted chrysanthemums enhance salt stress tolerance by integrating reactive oxygen species, soluble sugar, and proline
Wenjie Li1 , Rui Meng1 , Ye Liu1 , Sumei Chen1 , Jiafu Jiang1 , Likai Wang1 , Shuang Zhao1 , Zhenxing Wang1 , Weimin Fang1 , Fadi Chen1 , and Zhiyong Guan,1
1State Key Laboratory of Crop Genetics and Germplasm Enhancement, Key Laboratory of Landscaping, Ministry of Agriculture and Rural Affairs, College of Horticulture, Nanjing Agricultural University, Nanjing 210095, China
*Corresponding author. E-mail: guanzhy@njau.edu.cn

Horticulture Research 9,
Article number: uhac073 (2022)
doi: https://doi.org/10.1093/hr/uhac073
Views: 200

Received: 17 Nov 2021
Accepted: 16 Mar 2022
Published online: 23 Mar 2022

Abstract

Chrysanthemum, one of the most important commercial ornamental crops, is susceptible to salinity, which limits its cultivation and application in coastal and inland saline areas. Grafting is widely used to improve the salt tolerance of horticultural crops, but the mechanisms of grafted chrysanthemum responses to salt stress remain unclear. In this study, we showed that heterografted chrysanthemums with Artemisia annua as rootstock exhibited increased salt tolerance compared with self-grafted and self-rooted chrysanthemums. Under high salt stress, the roots of heterografted chrysanthemums enrich Na+, resulting in a reduction of Na+ toxicity in the scion, with only a small amount of Na+ being transported to the leaves. On the other hand, the roots of heterografted chrysanthemums alleviated high Na+ stress via enhanced catalase enzyme activity, downregulation of the expression of reactive oxygen species (ROS) accumulation-related genes, massive accumulation of soluble sugars and proline, and upregulation of the expression of heat shock protein-related genes to enhance salt tolerance. In addition, the leaves of heterografted chrysanthemums respond to low Na+ stress by increasing peroxidase enzyme activity and soluble sugar and proline contents, to maintain a healthy state. However, self-grafted and self-rooted plants could not integrate ROS, soluble sugars, and proline in response to salt stress, and thus exhibited a salt-sensitive phenotype. Our research reveals the mechanisms underlying the increased salt tolerance of heterografted chrysanthemums and makes it possible to have large-scale cultivation of chrysanthemums in saline areas.