I am currently focusing on Iron uptake and homeostasis in Arabidopsis.

 I had previously studied other aspects of plant development and stress responses.

(1) A number of plant cDNAs enhance stress tolerance in fission yeast S. pombe. I focused on two genes involved in two aspects of stress biology.

(a) OXS2 : Stress-induced reproduction.

OXS2 is a nucleo-cytoplasmic shuttling transcription factor. The  EXPORTIN1-mediated localization of OXS2 in the cytoplasm is stress-sensitive. Upon translocation in the nucleus, OXS2 targets floral integrators.  

(b) OXS3 : Epigenetics.

OXS3 is a plant-specific protein that protects cells from oxidative stress. OXS3 is found in discrete regions of the chromatin and resembles chromatin-modifying enzymes such as Histone Acetyl Transferases. It is yet unknown whether OXS3 protects the chromatin or changes its transcriptional selectivity to activate or repress genes important for the stress response.

(2) "Cargo" proteins, like OXS2, are actively exported from the nucleoplasm by EXPORTIN1/CRM1 (XPO1) proteins. This nuclear export depends upon the presence of a small leucine-rich sequence called  a Nuclear Export Signal (NES) within the cargo. There are two XPO1 loci in Arabidopsis for which we isolated loss-of-function alleles. We showed that in sesquimutant plants, 50% of the ovules were affected. In cases of fertilization, a wild type allele of XPO1, brought by the sperm cell, could not rescue the mutant ovules and the embryo did not develop. 

(3) The zygote of most plants divides into two asymmetrical cells. The small cell, distal to the mycropyle, generates the embryo proper and the large cell develops into a single file of 8-10 cells called the suspensor which ultimately degenerates. The study of a promoter trap line specifically active in suspensor cells of the Arabidopsis embryo revealed that the associated locus encodes a cytotoxic peptide with an amphiphillic alpha-helix. The peptide, named Kiss Of Death (KOD), is involved in the developmental cell death of the suspensor.