Ethylene Response Factors MbERF4 and MbERF72 Suppress Iron Uptake in Woody Apple Plants by Modulating Rhizosphere pH. (23rd December 2019)

• Record Type: Journal Article
• Authors: Zhang, Guifen; Liu, Wei; Feng, Yi; Li, Duyue; Li, Keting; Sun, Qiran; Zhai, Longmei; Wu, Ting; Zhang, Xinzhong; Xu, Xuefeng; Wang, Yi; Han, Zhenhai
• Is Part Of: Plant & cell physiology. Volume 61:Number 4(2020)
• Page Start: 699
• Page End: 711
• Publication Date: 2019-12-23
• Subjects: Apple rootstock -- Ethylene response factor -- Fe deficiency -- MbHA2 -- Transcription factor; Plant physiology -- Periodicals; Microbiology -- Periodicals; Cytology -- Periodicals; Cell Physiology -- Periodicals; Plant Physiological Phenomena -- Periodicals; Cytology; Microbiology; Plant physiology; Periodicals; 571.205
• DOI: 10.1093/pcp/pcz234
• Languages: English
• ISSNs: 0032-0781

Abstract

Abstract: Iron (Fe) deficiency limits the yield of fruit trees. When subjected to Fe deficiency, H + secretion increases in the rhizosphere of dicotyledonous plants and pH decreases. This leads to the acidification of the soil and promotes Fe 3+ to Fe 2+ conversion, which plants can better uptake. This study investigated the relationship between two inhibitory transcription factors (ethylene response factors MbERF4 and MbERF72) and the H + -ATPase gene MbHA2 . Two species of apple woody plants were studied: the Fe-inefficient Malus baccata and the Fe-efficient Malus xiaojinensis . Yeast one-hybrid and electrophoretic mobility shift assays showed that both MbERF4 and MbERF72 bind to the GCC cassette (AGCCGCC) of the MbHA2 promoter. Moreover, yeast two-hybrid and bimolecular fluorescence complementation assays showed that MbERF4 interacts with MbERF72. Furthermore, β-glucuronidase and luciferase reporter assays showed that the MbERF4- and MbERF72-induced repression of MbHA2 expression is synergistic. Virus-induced gene silencing of MbERF4 or MbERF72 increased MbHA2 expression, and thus lowered the rhizosphere pH in M. baccata . Consequently, the high expressions of MbERF4 and MbERF72 induced by Fe deficiency contributed to the Fe sensitivity of M. baccata . Moreover, the low expressions of MxERF4 and MxERF72 contributed to the Fe-deficiency tolerance of M. xiaojinensis via different binding conditions to the HA2 promoter. In summary, this study identified the relationship of two inhibitory transcription factors with the H + -ATPase gene and proposed a model in which ERF4 and ERF72 affect the rhizosphere pH in response to Fe deficiency.