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Mechanism of Dehydrin MsDHN1 Improving Al Tolerance of Alfalfa Revealed

August 30, 2021      Author:

Recently, the team led by Prof. An Yuan from the School of Agriculture and Biology, SJTU had their new findings published on the website of Plant Journal, titled “Dehydrin MsDHN1 improves aluminum tolerance of alfalfa (Medicago sativa L.) by affecting oxalateexudation from root tips”.

Alfalfa is a perennial legume forage with high nutritional value and good economic benefits. In southern China, due to the acidity of the soil, the active aluminum ion (Al3+) in the soil severely restricts the growth of alfalfa, thus affecting the development of animal husbandry in the southern region.

Dehydratin is a type of late embryogenesis abundant protein (LEA) and also an important stress response protein in plants. Alfalfa MsDHN1 is a typical intrinsically disordered protein, which can form dimers in plants and has high expression in root vascular bundles. The study found that the alfalfa SK3 dehydrogen MsDHN1 significantly alleviated the aluminum toxicity of alfalfa by increasing the secretion of oxalic acid from alfalfa root tips. At the same time, aquaporins (MsPIP2;1 and MsTIP1;1) interact with MsDHN1 and may play a role in aluminum-induced Oxalic acid secretion.

Dr. Lv Aimin (now a postdoctoral fellow in the research group), who graduated from the School of Agriculture and Biology, SJTU, is the first author of the paper, and Prof. An Yuan is the corresponding author. Doctoral students Wen Wuwu, Fan Nana, post-doctoral fellow Su Liantai and Associate Professor Zhou Peng also participated in the research. This work was funded by the National Natural Science Foundation of China and the National Key Research and Development Program.

 

 

Source: School of Agriculture and Biology, SJTU

Translated by Fu Jing

 

 

SUMMARY:

A SK3-type dehydrin MsDHN1 was cloned from alfalfa (Medicago sativa L.). Its function and gene regulatory pathways were studied via overexpression and suppression of MsDHN1 in alfalfa seedlings or hairy roots. The results showed that MsDHN1 is a typical intrinsically disordered protein that exists in the form of monomers and homodimers in alfalfa. The plant growth rates increased as a result of MsDHN1 overexpression (MsDHN1-OE) and decreased upon MsDHN1 suppression (MsDHN1-RNAi) in seedlings or hairy roots of alfalfa compared with the wild-type or the vector line under Al stress. MsDHN1 interacting with aquaporin (AQP) MsPIP2;1 and MsTIP1;1 positively affected oxalate secretion from root tips and Al accumulation in root tips. MsABF2 was proven to be an upstream transcription factor of MsDHN1 and activated MsDHN1 expression by binding to the ABRE element of the MsDHN1 promoter. The transcriptional regulation of MsABF2 on MsDHN1 was dependent on the abscisic acid signaling pathway. These results indicate that MsDHN1 can increase alfalfa tolerance to Al stress via increasing oxalate secretion from root tips, which may involve in the interaction of MsDHN1 with two AQP.