Journal
PLANT PHYSIOLOGY
Volume 183, Issue 2, Pages 750-764Publisher
AMER SOC PLANT BIOLOGISTS
DOI: 10.1104/pp.20.00208
Keywords
-
Categories
Funding
- National Key Research and Development Program of China [2018YFD1000200]
- National Natural Science Foundation of China [31972375, 31772288]
- Ministry of Agriculture of China [CARS-27]
- Shandong Province [SDAIT-06-03]
- Nanjing Agricultural University [ZW201805]
Ask authors/readers for more resources
Under high nitrate, BT2 ubiquitinates a bHLH transcription factor, reducing malate-associated gene transcription levels, thus controlling malate accumulation and vacuolar acidification. Excessive application of nitrate, an essential macronutrient and a signal regulating diverse physiological processes, decreases malate accumulation in apple (Malus domestica) fruit, but the underlying mechanism remains poorly understood. Here, we show that an apple BTB/TAZ protein, MdBT2, is involved in regulating malate accumulation and vacuolar pH in response to nitrate. In vitro and in vivo assays indicate that MdBT2 interacts directly with and ubiquitinates a bHLH transcription factor, MdCIbHLH1, via the ubiquitin/26S proteasome pathway in response to nitrate. This ubiquitination results in the degradation of MdCIbHLH1 protein and reduces the transcription of MdCIbHLH1-targeted genes involved in malate accumulation and vacuolar acidification, includingMdVHA-A, which encodes a vacuolar H+-ATPase, andMdVHP1, which encodes a vacuolar H+-pyrophosphatase, as well asMdALMT9, which encodes an aluminum-activated malate transporter. A series of transgenic analyses in apple materials including fruits, plantlets, and calli demonstrate that MdBT2 controls nitrate-mediated malate accumulation and vacuolar pH at least partially, if not completely, via regulating the MdCIbHLH1 protein level. Taken together, these findings reveal that MdBT2 regulates the stability of MdCIbHLH1 via ubiquitination in response to nitrate, which in succession transcriptionally reduces the expression of malate-associated genes, thereby controlling malate accumulation and vacuolar acidification in apples under high nitrate supply.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available