LONO1 encoding a nucleoporin is required for embryogenesis and seed viability in Arabidopsis.

Christopher Braud,Wenyan Xiao,Wenguang Zheng

doi:10.1104/pp.112.202192

Christopher Braud, Wenyan Xiao + Show 1 more

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https://doi.org/10.1104/pp.112.202192

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Journal: Plant Physiology	Publication Date: Aug 16, 2012
Citations: 19	License type: CC BY 4.0

Affiliation: Saint Louis University

Abstract

Early embryogenesis in Arabidopsis (Arabidopsis thaliana) is distinguished by a predictable pattern of cell divisions and is a good system for investigating mechanisms of developmental pattern formation. Here, we identified a gene called LONO1 (LNO1) in Arabidopsis in which mutations can abolish the first asymmetrical cell division of the zygote, alter planes and number of cell divisions in early embryogenesis, and eventually arrest embryo development. LNO1 is highly expressed in anthers of flower buds, stigma papilla of open flowers, and embryo and endosperm during early embryogenesis, which is correlated with its functions in reproductive development. The homozygous lno1-1 seed is not viable. LNO1, a homolog of the nucleoporin NUP214 in human (Homo sapiens) and Nup159 in yeast (Saccharomyces cerevisiae), encodes a nucleoporin protein containing phenylalanine-glycine repeats in Arabidopsis. We demonstrate that LNO1 can functionally complement the defect in the yeast temperature-sensitive nucleoporin mutant nup159. We show that LNO1 specifically interacts with the Arabidopsis DEAD-box helicase/ATPase LOS4 in the yeast two-hybrid assay. Furthermore, mutations in AtGLE1, an Arabidopsis homolog of the yeast Gle1 involved in the same poly(A) mRNA export pathway as Nup159, also result in seed abortion. Our results suggest that LNO1 is a component of the nuclear pore complex required for mature mRNA export from the nucleus to the cytoplasm, which makes LNO1 essential for embryogenesis and seed viability in Arabidopsis.

Highlights

Embryogenesis in Arabidopsis (Arabidopsis thaliana) is distinguished by a predictable pattern of cell divisions and is a good system for investigating mechanisms of developmental pattern formation
We found that LNO1 (At1G55540) was required for seed viability in Arabidopsis
To further confirm that the seed abortion phenotype was caused by the T-DNA insertional mutation in LNO1, we transformed the LNO1 transgene under the control of the 35S promoter into LNO1/lno1-1 heterozygous plants, and the result showed that the transgene was able to complement the mutant phenotype and restored the seed viability in the homozygous mutant lno1-1/lno1-1 background

Summary

Introduction

Embryogenesis in Arabidopsis (Arabidopsis thaliana) is distinguished by a predictable pattern of cell divisions and is a good system for investigating mechanisms of developmental pattern formation. We identified a gene called LONO1 (LNO1) in Arabidopsis in which mutations can abolish the first asymmetrical cell division of the zygote, alter planes and number of cell divisions in early embryogenesis, and eventually arrest embryo development. Mutations in some genes can make the basal lineage cells adopt an embryonic cell fate by undergoing longitudinal cell divisions (Vernon and Meinke, 1994; Zhang and Somerville, 1997; Lotan et al, 1998; Lukowitz et al, 2004). PIN proteins control polar auxin transport and establish auxin gradients during embryogenesis, which are required for early embryo pattern formation in Arabidopsis (Friml et al, 2003; Weijers et al, 2005). RECEPTOR-LIKE PROTEIN KINASE1 and TOADSTOOL2 are critical for embryonic pattern formation (Nodine et al, 2007)

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