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Isolation and characterization of a wheat F8-1 homolog required for physiological male sterility induced by a chemical hybridizing agent (CHA) SQ-1

Song, Yulong, Wang, Junwei, Zhang, Gaisheng, Zhao, Xinliang, Zhang, Pengfei, Niu, Na, Ma, Shoucai
Euphytica 2015 v.205 no.3 pp. 707-720
RNA interference, Secale cereale, Triticum aestivum, Triticum turgidum subsp. durum, Triticum urartu, abortion (plants), amino acids, anthers, consensus sequence, expressed sequence tags, genes, isoelectric point, male fertility, males, molecular weight, open reading frames, plant breeding, pollen, wheat
We investigated the relationship between a pollen-specific protein homolog and pollen abortion in an SQ-1-induced male sterile line of wheat (Triticum aestivum L.). We previously determined that EST S414 (Ta20678) was obviously down-regulated in a line of Xinong 1376 wheat in which male sterility was induced by SQ-1 (a chemical hybridizing agent). In the present study, we obtained the full sequence of F8-1 from wheat. The open reading frame sequence of the F8-1 gene was 495 bp, encoding 165 amino acid residues with a predicted molecular weight of 18.2759 kDa and an isoelectric point of 4.86. This sequence was identified as a Secale cereale × Triticum durum F8-4 homolog with 100 % identity. The amino acids represent a conserved domain in pollen Ole e I that contains the consensus sequence Q-G-R-V-Y-C-D-T-C-R. The protein has a close evolutionary relationship with orthologs in S. cereale × T. durum and Triticum urartu, consisting of 9.09 % alpha helix, 24.85 % extended strand, and 66.06 % random coil. F8-1 was only expressed in anthers during the binucleate and trinucleate stages and expression gradually decreased from the binucleate stage to the trinucleate stage. The expression of F8-1 gene of physiological male sterility 1376 (PHYMS-1376) was lower than that of 1376 at both the binucleate and trinucleate stages. Subcellular localization showed that the F8-1 protein was expressed at the nucleus. RNAi tests showed that down-regulation of the F8-1 was associated with an increase in the percentage of pollen abortion. Therefore, F8-1 is a positive regulator of physiological male sterility.