Characterization of two non-homoeologous nuclear genes encoding mitochondrial alternative oxidase in common wheat.

Abstract

Mitochondrial alternative oxidase (AOX) is the terminal oxidase responsible for cyanide-insensitive and salicylhydroxamic acid-sensitive respiration. We have isolated two non-homoeologous genes ( Waox1a and Waox1c ) encoding AOX proteins from common wheat ( Triticum aestivum L.). These two genes were orthologous to rice AOX1a and AOX1c , and their exon/intron structure was conserved, as it is in most other plant AOX genes. Southern blot analysis indicated that both Waox1a and Waox1c were located in at least three homoeologous loci and that additional AOX genes with lower homology were present in the genome of common wheat. The Waox1a and Waox1c loci were respectively assigned to the homoeologous group 2 and 6 chromosomes. The steady-state level of Waox1a and Waox1c transcripts increased under cold stress, while only that of Waox1a was increased by cyanide treatment.

Expression profiles of respiratory components associated with mitochondrial biogenesis during germination and seedling growth under normal and restricted conditions in wheat

“…Since we extracted mitochondrial and total proteins using reducing buffer, we detected only a single monomeric band corresponding to the reduced form of AOX. The apparent molecular mass of this monomeric form on the polyacrylamide gels was about 40 kDa, which was higher than 37 kDa deduced from the cDNA sequences of the two wheat Aox genes (Takumi et al, 2002). A similar size discrepancy was reported in soybean (Finnegan et al, 1997).…”

Alternative oxidase: an inter-kingdom perspective on the function and regulation of this broadly distributed 'cyanide-resistant' terminal oxidase

“…AOX is a nuclear-encoded gene in eukaryotes and occurs as a multigene family in many plants, including soybean, A. thaliana, tobacco, corn, mango, sugarcane, wheat, cotton and rice (Whelan et al 1995(Whelan et al , 1996Saisho et al 1997;Considine et al 2001;Karpova et al 2002;Saika et al 2002;Takumi et al 2002;Borecky et al 2006;Li et al 2008). In angiosperms, two types of AOX genes exist: AOX1 genes have been found in all angiosperms examined to date, while AOX2 genes appear to be limited to dicot speces (Considine et al 2002).…”

Mitochondrial biogenesis as revealed by mitochondrial transcript profiles during germination and early seedling growth in wheat

“…Primer sequences for wheat rps7 and rps12 were after Tsukamoto et al (2000), for Mn-SOD after Baek and Skinner (2003), for Whlp, TaMRPL5 and TaMRPL11 after Mizumoto et al (2004) and for Waox1a from Takumi et al (2002). These rice and wheat genes were amplified from DNA of "Nipponbare" and "CS", respectively, by PCR using rTag DNA polymerase (TOYOBO, Osaka, Japan).…”