IRE1, a component of the unfolded protein response signaling pathway, protects pollen development in Arabidopsis from heat stress.
The unfolded protein response (UPR) is activated by various stresses during vegetative development in Arabidopsis, but is constitutively active in anthers of unstressed plants. To understand the role of the UPR during reproductive development, we analyzed a double mutant, ire1a ire1b. The double mutant knocks out the RNA-splicing arm of the UPR signaling pathway. It is fertile at room temperature but male sterile at modestly elevated temperature (ET). The conditional male sterility in the mutant is a sporophytic trait, and when the double mutant was grown at ET, defects appeared in the structure of the tapetum. As a result, the tapetum in the double mutant failed to properly deposit the pollen coat at ET, which made pollen grains clump and prevented their normal dispersal. IRE1 is a dual protein kinase/ribonuclease involved in the splicing of bZIP60 mRNA, and through complementation analysis of various mutant forms of IRE1b it was demonstrated that the ribonuclease activity of IRE1 was required for protecting male fertility from ET. It was also found that overexpression of SEC31A rescued the conditional male sterility in the double mutant. SEC31A is involved in trafficking from the endoplasmic reticulum to Golgi and a major target of the IRE1-mediated UPR signaling in stressed seedlings. Thus, IRE1, a major component of the UPR, plays an important role in protecting pollen development from ET.
Department of Computer Science, Iowa State University, Ames, IA, 50011, USA.
Yan
Y
Deng
Plant Sciences Institute, Iowa State University, Ames, IA, 50011, USA.
Renu
R
Srivastava
Department of Botany, University of British Columbia, Vancouver, BC, V6T 1Z4, Canada.
Teagen D
TD
Quilichini
Department of Plant Pathology and Microbiology, Iowa State University, Ames, IA, 50011, USA.
Haili
H
Dong
Department of Genetics, Development and Cell Biology, Iowa State University, Ames, IA, 50011, USA.
Yan
Y
Bao
Department of Genetics, Development and Cell Biology, Iowa State University, Ames, IA, 50011, USA.|Microscopy and NanoImaging Facility, Iowa State University, Ames, IA, 50011, USA.
Harry T
HT
Horner
Plant Sciences Institute, Iowa State University, Ames, IA, 50011, USA.|Department of Genetics, Development and Cell Biology, Iowa State University, Ames, IA, 50011, USA.
Stephen H
SH
Howell
D017360:Arabidopsis / Q000235:genetics / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D004721:Endoplasmic Reticulum / Q000378:metabolism; D035264:Flowers / Q000235:genetics / Q000378:metabolism; D018506:Gene Expression Regulation, Plant / Q000235:genetics / Q000502:physiology; D006056:Golgi Apparatus / Q000378:metabolism; D006358:Hot Temperature; D015398:Signal Transduction / Q000235:genetics / Q000502:physiology; D056811:Unfolded Protein Response / Q000235:genetics / Q000502:physiology*
D029681:Arabidopsis Proteins
Sec31; endoplasmic reticulum; heat stress; male gametophyte; tapetum; vesicle trafficking