The regulatory module MdBT2–MdMYB88/MdMYB124–MdNRTs regulates nitrogen usage in apple

Abstract

Less than 40% of the nitrogen (N) fertilizer applied to soil is absorbed by crops. Thus, improving the N use efficiency of crops is critical for agricultural development. However, the underlying regulation of these processes remains largely unknown, particularly in woody plants. By conducting yeast two-hybrid assays, we identified one interacting protein of MdMYB88 and MdMYB124 in apple (Malus × domestica), namely BTB and TAZ domain protein 2 (MdBT2). Ubiquitination and protein stabilization analysis revealed that MdBT2 ubiquitinates and degrades MdMYB88 and MdMYB124 via the 26S proteasome pathway. MdBT2 negatively regulates nitrogen usage as revealed by the reduced fresh weight, dry weight, N concentration, and N usage index of MdBT2 overexpression calli under low-N conditions. In contrast, MdMYB88 and MdMYB124 increase nitrate absorption, allocation, and remobilization by regulating expression of MdNRT2.4, MdNRT1.8, MdNRT1.7, and MdNRT1.5 under N limitation, thereby regulating N usage. The results obtained illustrate the mechanism of a regulatory module comprising MdBT2–MdMYB88/MdMYB124–MdNRTs, through which plants modulate N usage. These data contribute to a molecular approach to improve the N usage of fruit crops under limited N acquisition.

Magnesium promotes nitrate uptake by increasing shoot-to-root translocation of sorbitol in apple seedlings

“…According to previous studies (Tahir et al, 2021Zhang et al, 2021),MdNRT1.1 , MdNRT1.2 , MdNRT1.5 , MdNRT1.7 ,MdNRT1.8 , MdNRT2.1 , MdNRT2.2 , MdNRT2.4 andMdNRT2.5 are involved in N uptake and transport in apples, and they are all expressed in roots. To further explore how Mg promotes N uptake, we measured the expression of above MdNRTs .…”

“…According to the previous research and the purpose of our experiment Tahir et al, 2021Zhang et al, 2021, 9 NRTs and 6 SUTs were selected to determine the relative expression. Total RNA was extracted from about 60 mg of fresh leaves or roots tissues using the RNAisoPlus (Takara, Otsu, Shiga, Japan).…”

VqWRKY56 interacts with VqbZIPC22 in grapevine to promote proanthocyanidin biosynthesis and increase resistance to powdery mildew

“…As controls, A. tumfaciens GV3101 strains containing fusion plasmids, nLUC‐VqWRKY56 with cLuc, nLuc with cLUC‐VqbZIPC22, and nLuc with cLuc, were mixed with p19 (nLUC‐VqWRKY56 : nLUC : cLUC‐VqbZIPC22 : p19 = 1 : 1 : 1; nLUC : cLUC‐VqbZIPC22 : p19 = 1 : 1 : 1; nLUC : cLUC : p19 = 1 : 1 : 1, OD 600 = 0.4) and then co‐injected into tobacco leaves. At 48 h, the abaxial sides of tobacco leaves were coated with 1‐mM luciferin and imaged with a CCD instrument (Lumazone Pylon 2048B) (D. Zhang et al ., 2021).…”

Engineering drought-tolerant apple by knocking down six GH3 genes and potential application of transgenic apple as a rootstock

“…About 0.5 mg of the dry weight of leaves was used for soluble sugar and starch extractions, and the contents were determined by an anthrone colorimetric method [ 71 ]. Approximately 0.5 mg of dry weight of leaves was used for total N extraction, and the content was determined as described previously [ 72 ]. The fifth to ninth leaves from the base of the stems were used as plant materials.…”