The LuWD40-1 Gene Encoding WD Repeat Protein Regulates Growth and Pollen Viability in Flax (Linum Usitatissimum L.)

Abstract

As a crop, flax holds significant commercial value for its omega-3 rich oilseeds and stem fibres. Canada is the largest producer of linseed but there exists scope for significant yield improvements. Implementation of mechanisms such as male sterility can permit the development of hybrids to assist in achieving this goal. Temperature sensitive male sterility has been reported in flax but the leakiness of this system in field conditions limits the production of quality hybrid seeds. Here, we characterized a 2,588 bp transcript differentially expressed in male sterile lines of flax. The twelve intron gene predicted to encode a 368 amino acid protein has five WD40 repeats which, in silico, form a propeller structure with putative nucleic acid and histone binding capabilities. The LuWD40-1 protein localized to the nucleus and its expression increased during the transition and continued through the vegetative stages (seed, etiolated seedling, stem) while the transcript levels declined during reproductive development (ovary, anthers) and embryonic morphogenesis of male fertile plants. Knockout lines for LuWD40-1 in flax failed to develop shoots while overexpression lines showed delayed growth phenotype and were male sterile. The non-viable flowers failed to open and the pollen grains from these flowers were empty. Three independent transgenic lines overexpressing the LuWD40-1 gene had ∼80% non-viable pollen, reduced branching, delayed flowering and maturity compared to male fertile genotypes. The present study provides new insights into a male sterility mechanism present in flax.

Genome-wide identification, characterization, and expression profile of aquaporin gene family in flax (Linum usitatissimum)

“…RMA normalized gene-level signal intensity (log2) values for the unigenes exhibiting similarity to AQPs were used from all replicates and averaged further. Similarly, the normalized RNA-Seq dataset generated by Kumar, et al 77. available at http://linum.ca/downloads/RNAseq was also used to analyze the expression of AQPs.…”

Biotechnology of fibrous flax in Europe and China

“…It was seen that the LuWD40-1 gene encoding WD Repeat Protein regulates proper growth and pollen viability in flax (Kumar et al, 2013). It turned out that overproduction of WD Repeat Protein led to ca.…”

ARABIDOPSIS POLLEN ABORTION MUTANT 2, Encoding an Unknown Protein with Three WD40-Repeats, Is Essential for Late Pollen Mature in Arabidopsis thaliana

“…The OsLIS-L1 gene encoding the lissencephaly type-1-like protein with WD40 repeats is involved in plant height and male gametophyte formation in rice [22]. The LuWD40-1 gene encoding a WD40 repeat protein regulates growth and pollen viability in flax (Linum usitatissimum L.)) [23]. The JINGUBANG gene encodes a putative hydrophilic protein containing seven WD40 repeats, which is a negative regulator of pollen germination and prevents pollination in moist environments [24].…”