A broadly sampled 3-loci plastid phylogeny of Atraphaxis (Polygoneae, Polygonoideae, Polygonaceae) reveals new taxa: II. Atraphaxis selengensis spec. nov., and A. davurica Jaub. &amp; Spach from Russian Transbaikalia

Maximum Likelihood (ML) and Bayesian analyses (BI) applied for 3-plastid loci (cpDNA trnL(UAA) intron, trnL–trnF IGS, and rpl32–trnL(UAG) IGS regions) / 55 tips of Atraphaxis revealed a subclade of two endemics from Transbaikalia (Dahuria) which are often mistaken for A. pungens and A. frutescens but phylogenetically distant from both. Atraphaxis selengensis is a species new to science which inhabits dune sands along the Selenga and Chikoy rivers and has specific morphology of perianth, fruits, ochreas, leaf blades, and pollen. Atraphaxis davurica inhabits stony mountain steppe in Buryatia and Chita region and differs from A. pungens and A. frutescens by longer ochreas, fruits, styles and stigmas extended to ends. Two varieties recognized by Ledebour in plants from Russian Transbaikalia have no clear morphological and molecular distinctions, but the plants from Khentei-Chikoy Highlands subtly differ in leaf ratio (length/width), bark colour, and a single-nucleotide substitution in trnL–F region. These plants are described as A. davurica var. chikoensis var. nov. Morphological descriptions of A. selengensis and A. davurica are supplied with LM and SEM images and a distributional map. Atraphaxis frutescens and A. pungens are absent from Russian Transbaikalia but distributed in Altai, Tuva, Khakassia, Mongolia and China.

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A single nucleotide substitution in the coding region of Ogura male sterile gene, orf138, determines effectiveness of a fertility restorer gene, Rfo, in radish

Molecular Genetics and Genomics ◽

10.1007/s00438-021-01777-y ◽

2021 ◽

Author(s):

Hiroshi Yamagishi ◽

Megumi Jikuya ◽

Kanako Okushiro ◽

Ayako Hashimoto ◽

Asumi Fukunaga ◽

...

Keyword(s):

Male Sterility ◽

Nucleotide Substitution ◽

Fertility Restoration ◽

Type A ◽

Restorer Gene ◽

Single Nucleotide Substitution ◽

Coding Region ◽

Fertility Restorer ◽

Single Nucleotide ◽

Fertility Restorer Gene

AbstractCytoplasmic male sterility (CMS) observed in many plants leads defect in the production of functional pollen, while the expression of CMS is suppressed by a fertility restorer gene in the nuclear genome. Ogura CMS of radish is induced by a mitochondrial orf138, and a fertility restorer gene, Rfo, encodes a P-type PPR protein, ORF687, acting at the translational level. But, the exact function of ORF687 is still unclear. We found a Japanese variety showing male sterility even in the presence of Rfo. We examined the pollen fertility, Rfo expression, and orf138 mRNA in progenies of this variety. The progeny with Type H orf138 and Rfo showed male sterility when their orf138 mRNA was unprocessed within the coding region. By contrast, all progeny with Type A orf138 were fertile though orf138 mRNA remained unprocessed in the coding region, demonstrating that ORF687 functions on Type A but not on Type H. In silico analysis suggested a specific binding site of ORF687 in the coding region, not the 5′ untranslated region estimated previously, of Type A. A single nucleotide substitution in the putative binding site diminishes affinity of ORF687 in Type H and is most likely the cause of the ineffectiveness of ORF687. Furthermore, fertility restoration by RNA processing at a novel site in some progeny plants indicated a new and the third fertility restorer gene, Rfs, for orf138. This study clarified that direct ORF687 binding to the coding region of orf138 is essential for fertility restoration by Rfo.

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