Inhibition of a Basal Transcription Factor 3-Like Gene Osj10gBTF3 in Rice Results in Significant Plant Miniaturization and Typical Pollen Abortion

Abstract

BTF3, which was originally recognized as a basal transcription factor, has been known to be involved in transcription initiation, translational regulation and protein localization in many eukaryotic organisms. However, its function remains largely unknown in plant species. In the present study, we analyzed a BTF3-related sequence in Oryza sativa L. subsp. japonica, which shares the conserved domain of a nascent polypeptide-associated complex with human BTF3, and was referred to as Osj10gBTF3. The expression of Osj10gBTF3 was primarily constitutive and generally modulated by salt, high temperature and exogenous phytohormone stress. The Osj10gBTF3::EGFP (enhanced green fluorescence protein) fusion protein was localized in both the nucleus and cytoplasmic membrane system. Inhibition of Osj10gBTF3 led to significant morphological changes in all detected tissues and organs, with a reduced size of between 25% and 52%. Furthermore, the pollen that developed was completely sterile, which was correlated with the altered expression of two Rf (fertility restorer)-like genes that encode pentatricopeptide repeat-containing proteins OsPPR676 and OsPPR920, translational initiation factors OseIF3e and OseIF3h, and the heat shock protein OsHSP82. These findings were verified through a yeast two-hybrid assay using a Nipponbare callus cDNA library as bait followed by the reverse transcription-PCR analysis of total leaf or anther RNAs. Our demonstration of the important role of Osj10gBTF3 in rice growth and development provides new insights showing that more complex regulatory functions are associated with BTF3 in plants.

Basal Transcription Factor 3 Plays an Important Role in Seed Germination and Seedling Growth of Rice

“…RNAs extractions, the full length of cDNA synthesis, were carried out using the BTF3 gene-specific primers via procedures as described by Wang et al [6]. The amplified products of cDNA were cloned into a pMD18-T vector (TaKaRa).…”

“…The amplified products of cDNA were cloned into a pMD18-T vector (TaKaRa). RNAi repression vector was constructed as suggested by Wang et al [6]. The resultant vector was incorporated into the EHA105 ( A. tumefaciens strain), which was used to infect rice embryogenic calli raised from mature seeds of Nipponbare to produce transformed calli.…”

“…Among these TFs, the basal transcription factors 3 (BTF3) is one of the extremely important transcription factors due to their role in various biotic and abiotic stress processes [3–6] and different physiological and developmental mechanisms such as ionic homeostasis [7], photosynthetic rate [8], and pollen development [6] in plants.…”

“…Recently, in rice, Wang et al [6] have demonstrated that BTF3 plays important role in plant growth and development. However, the function of different variants of OsBTF3 in seed germination and seedling growth is not yet documented.…”

Direct Detection of Transcription Factors in Cotyledons during Seedling Development Using Sensitive Silicon-Substrate Photonic Crystal Protein Arrays

“…This finding meshes well with the results from our study, in that this gene's expression peaked at stage 4 (in the middle of the seedling cotyledon's functional transition from yellow storage organ to green photosynthesizing organ), with the protein increasing dramatically in abundance coincident with the greening of the seedling cotyledon. Other studies have suggested that BTF3 has roles in biotic and abiotic stress response and pollen development (Huh et al, 2012;Wang et al, 2012;Kang et al, 2013).…”