A Mutable Albino Allele in Rice Reveals that Formation of Thylakoid Membranes Requires the SNOW-WHITE LEAF1 Gene

Abstract

Active DNA transposons are important tools for gene functional analysis. The endogenous non-autonomous transposon, nDart1-0, in rice (Oryza sativa L.) is expected to generate various transposon-insertion mutants because nDart1-0 elements tend to insert into genic regions under natural growth conditions. We have developed a specific method (nDart1-0-iPCR) for efficient detection of nDart1-0 insertions and successfully identified the SNOW-WHITE LEAF1 (SWL1) gene in a variegated albino (swl1-v) mutant obtained from the nDart1-promoted rice tagging line. The variegated albino phenotype was caused by insertion and excision of nDart1-0 in the 5'-untranslated region of the SWL1 gene predicted to encode an unknown protein with the N-terminal chloroplast transit peptide. SWL1 expression was detected in various rice tissues at different developmental stages. However, immunoblot analysis indicated that SWL1 protein accumulation was strictly regulated in a tissue-specific manner. In the swl1 mutant, formations of grana and stroma thylakoids and prolamellar bodies were inhibited. This study revealed that SWL1 is essential for the beginning of thylakoid membrane organization during chloroplast development. Furthermore, we provide a developmental perspective on the nDart1-promoted tagging line to characterize unidentified gene functions in rice.

Lipid Trafficking in Plant Cells

“…Direct evidence that VIPP1 induces vesicles is still lacking (reviewed in ), and there is conflicting evidence from its homolog in Synechocystis , which suggests that aberrant thylakoid structure in knockouts may be due to a direct effect on photosynthetic ability . Similarly, snow‐white leaf1 (SWL1) has been described as involved in thylakoid biogenesis in rice . It was shown to be important for development of chloroplasts from proplastids, but not for amyloplasts or etioplasts, indicating a specific role in thylakoid biogenesis; however, its direct function has not yet been shown.…”

Leaf Variegation and Impaired Chloroplast Development Caused by a Truncated CCT Domain gene inalbostriansBarley

“…Genes involved in the variegation pattern formation have been cloned in monocot and dicot species (e.g. Wu et al, 1999; Chen et al, 2000; Takechi et al, 2000; Prikryl et al, 2008; Hayashi-Tsugane et al, 2014; Wang et al, 2016; Zheng et al, 2016; Guan et al, 2017; Zagari et al, 2017). Despite the advances of identifying the underlying genes, insights to the molecular mechanisms controlling the phenomenon are rare (Sakamoto, 2003; Yu et al, 2007).…”

A gain-of-function Bushy dwarf tiller 1 mutation in rice microRNA gene miR156d caused by insertion of the DNA transposon nDart1

“…The tagging system is a powerful tool because nDart1 elements are actively transposed under natural growth conditions and tend to be integrated into genic regions, particularly into promoter-proximal genic regions, 0.5 kb in front of the putative initiation codons 13 . To effectively identify nDart1 insertion sites of the genome, the AFLP-based transposon display (TD) procedure, nDart-TD, and the iPCR-based procedure, nDart1-0-iPCR, were also developed 14 15 .…”