Rice OsDOF15 contributes to ethylene‐inhibited primary root elongation under salt stress

Abstract

Summary In early seedlings, the primary root adapts rapidly to environmental changes through the modulation of endogenous hormone levels. The phytohormone ethylene inhibits primary root elongation, but the underlying molecular mechanism of how ethylene‐reduced root growth is modulated in environmental changes remains poorly understood. Here, we show that a novel rice (Oryza sativa) DOF transcription factor OsDOF15 positively regulates primary root elongation by regulating cell proliferation in the root meristem, via restricting ethylene biosynthesis. Loss‐of‐function of OsDOF15 impaired primary root elongation and cell proliferation in the root meristem, whereas OsDOF15 overexpression enhanced these processes, indicating that OsDOF15 is a key regulator of primary root elongation. This regulation involves the direct interaction of OsDOF15 with the promoter of OsACS1, resulting in the repression of ethylene biosynthesis. The control of ethylene biosynthesis by OsDOF15 in turn regulates cell proliferation in the root meristem. OsDOF15 transcription is repressed by salt stress, and OsDOF15‐mediated ethylene biosynthesis plays a role in inhibition of primary root elongation by salt stress. Thus, our data reveal how the ethylene‐inhibited primary root elongation is finely controlled by OsDOF15 in response to environmental signal, a novel mechanism of plants responding to salt stress and transmitting the information to ethylene biosynthesis to restrict root elongation.

Ethylene: A Master Regulator of Salinity Stress Tolerance in Plants

“…Interestingly, SOS2 phosphorylates EIN3 and activates salinity-inducible ESE1 [68]. In rice, OsDOF15 was identified as a gene involved in the coordination between salinity and ethylene biosynthesis in rice to inhibit primary root development by affecting cell proliferation in the root apical meristem [69]. In addition, the expression levels of OsEIL2 were found to be upregulated during salinity stress in WT plants; however, OsEIL2 overexpression plants showed growth retardation with shortened roots and shoots than control plants [70].…”

Genome-Wide Association Study of Root System Development at Seedling Stage in Rice

“…The major root components, namely, the primary root, crown root, and lateral root, together comprise a complex root system, each part of which has diverse functions during different rice growth stages. For instance, primary roots are important for mineral nutrient acquisition and support shoot growth during the germination and young seedling growth stages [65]. The major functions of the crown and lateral roots are water and nutrient uptake and regulation of interactions between the plant and its environment [19].…”

Ethylene signaling in rice and Arabidopsis: New regulators and mechanisms

“…OsEIL1 and OsEIL2 may work in part by regulating OsHKT2;1 expression and Na + uptake in the roots (Yang et al, 2015b). In rice roots, the salt‐suppressed transcription factor OsDOF15 inhibits ethylene biosynthesis by directly binding to the promoter of OsACS1 , linking ethylene biosynthesis with salt stress in regulating primary root elongation (Qin et al, 2019b). A recent study showed that the ACC deaminase‐producing Burkholderia sp.…”