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Natural variation in cytokinin maintenance improves salt tolerance in apple rootstocks
Author(s) -
Feng Yi,
Liu Jing,
Zhai Longmei,
Gan Zengyu,
Zhang Guifen,
Yang Shuhua,
Wang Yi,
Wu Ting,
Zhang Xinzhong,
Xu Xuefeng,
Han Zhenhai
Publication year - 2019
Publication title -
plant, cell and environment
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.646
H-Index - 200
eISSN - 1365-3040
pISSN - 0140-7791
DOI - 10.1111/pce.13403
Subject(s) - rootstock , cytokinin , biology , salt (chemistry) , variation (astronomy) , horticulture , botany , chemistry , genetics , physics , gene , auxin , astrophysics
Plants experiencing salt‐induced stress often reduce cytokinin levels during the early phases of stress‐response. Interestingly, we found that the cytokinin content in the apple rootstock “robusta” was maintained at a high level under salt stress. Through screening genes involved in cytokinin biosynthesis and catabolism, we found that the high expression levels of IPT5b in robusta roots were involved in maintaining the high cytokinin content. We identified a 42 bp deletion in the promoter region of IPT5b , which elevated IPT5b expression levels, and this deletion was linked to salt tolerance in robusta×M.9 segregating population. The 42 bp deletion resulted in the deletion of a Proline Response Element (ProRE), and our results suggest that ProRE negatively regulates IPT5b expression in response to proline. Under salt stress, the robusta cultivar maintains high cytokinin levels as IPT5b expression cannot be inhibited by proline due to the deletion of ProRE, leading to improve salt tolerance.