Arabidopsis ERdj3B coordinates with ERECTA-family receptor kinases to regulate ovule development and the heat stress response.

The endoplasmic reticulum-localized DnaJ family 3B (ERdj3B), is a component of the stromal cell-derived factor 2 (SDF2)-ERdj3B-binding immunoglobulin protein (BiP) chaperone complex, which functions in protein folding, translocation, and quality control. We found that ERdj3B mutations affected integument development in the Ler ecotype but not in the Col-0 ecotype of Arabidopsis (Arabidopsis thaliana). Map-based cloning identified the ERECTA (ER) gene as a natural modifier of ERdj3B. The double mutation of ERdj3B and ER caused a major defect in the inner integument under heat stress. Additional mutation of the ER paralog ERECTA-LIKE 1 (ERL1) or ERL2 to the erdj3b er double mutant exacerbated the defective integument phenotype. The double mutation of ER and SDF2, the other component of the SDF2-ERdj3B-BiP complex, resulted in similar defects in the inner integument. Furthermore, both the protein abundance and plasma membrane partitioning of ER, ERL1, and ERL2 were markedly reduced in erdj3b plants, indicating that the SDF2-ERdj3B-BiP chaperone complex might control the translocation of ERECTA-family proteins from the endoplasmic reticulum to the plasma membrane. Our results suggest that the SDF2-ERdj3B-BiP complex functions in ovule development and the heat stress response in coordination with ERECTA-family receptor kinases.

[Analysis of histone modification of MtSERK1 during in vitro regeneration in Medicago truncatula].

Epigenetic modification, especially histone modification, plays an important role in maintaining plant genome stability, regulating gene expression and promoting regeneration in vitro. MtSERK1 is an important marker gene involved in establishing of embryogenic callus during in vitro regeneration of Medicago truncatula. In order to understand the regulation Epigenetic modification, especially histone modification, plays an important role in maintaining plant genome stability, regulating gene expression and promoting regeneration in vitro. MtSERK1 is an important marker gene involved in establishing of embryogenic callus during in vitro regeneration of Medicago truncatula. In order to understand the regulation relationship between dynamic histone modification and MtSERK1s expression during the processes of in vitro organogenesis, the expression of MtSERK1 was analyzed by qRT-PCR, and the modification status of H3K9me2, H3K4me3 and H3K9ac in the promoter region and different regions included in the gene body was analyzed by chromatin immunoprecipitation (ChIP). We found expression activation of MtSERK1 was related to the dynamic changes of histone H3K4me3 and H3K9ac in the 5' and 3' regions. This study will provide important theoretical guidance for understanding of the regulatory mechanism of MtSERK1 and also for establishing efficient genetic transformation system of Medicago truncatula.