Alstroemeria (Liliales) has two layers of petaloid tepals, in which the often spotted narrow inner tepals can be distinguished easily from the wider outer tepals. In order to explore this floral morphology in Alstroemeria, we investigated the tepal morphology and the expression patterns of three class B genes, whose homologs in eudicots have been shown previously to be involved in petal and stamen development. The two DEF-like genes (AlsDEFa and AlsDEFb) and the one GLO-like gene (AlsGLO) of Alstroemeria ligtu were isolated by rapid amplification of cDNA ends (RACE). Northern hybridization, reverse transcription-PCR (RT-PCR) and in situ hybridization analyses indicated that AlsDEFb and AlsGLO were expressed in whorls 1, 2 and 3 (outer tepals, inner tepals and stamens, respectively), whereas AlsDEFa expression was detected only in whorls 2 and 3. These results suggest that in A. ligtu, AlsDEFb and AlsGLO would participate in determining the organ identity of the two-layered petaloid tepals and stamens, which is in support of the modified ABC model. Additionally, the distinctive expression patterns of AlsDEFa and AlsDEFb might be related to morphological differences between the two-layered tepals.
MADS-box genes encode transcriptional regulators that are critical for a number of developmental processes. In the MADS-box gene family, the SEPAL-LATA (SEP) gene subfamily plays an important role in controlling the development of floral organs in flowering plants. To understand the molecular mechanisms of floral development in Asparagus, we isolated and characterized several SEP-like genes from dioecious Asparagus officinalis and hermaphrodite A. virgatus: AOMADS1, AOMADS2, AOMADS3, and AVMADS1, AVMADS2, AVMADS3, respectively. Through alignment of the predicted amino acid sequences of various SEP-like genes, we defined three characteristic motifs in the C-terminal region of the genes: SEP motif I, SEP/ AGL6 motif, and SEP motif II. Of the genes we isolated, AOMADS3 and AVMADS3 had lost the SEP motif II. Phylogenetic analysis revealed that AOMADS1, AO-MADS2, AVMADS1, and AVMADS2 were closely related to SEP3 from Arabidopsis, whereas AOMADS3 and AVMADS3 were classified in different clade which is far related to SEP3 gene. Northern hybridization and RT-PCR showed that three SEP-like genes in A. officinalis were specifically expressed in the flower buds. In addition, PCR RFLP showed that there was no significant difference in the amount of transcripts of AO-MADS1 and AOMADS2. These results suggest that AOMADS1 and AOMADS2 may be redundant genes. In contrast, the expression of AOMADS3 was weaker than that of AOMADS1 or AOMADS2, suggesting that the function of AOMADS3 may be different than that of AOMADS1 or AOMADS2.
Bacteria that exhibit ionic-liquid (IL) tolerance are useful in chemical industries using renewable carbon sources pre-treated by ILs to produce biofuels and fine chemicals. An IL, 1-butyl-3-methylimidazolium chloride ([BMIM]Cl), has a remarkable ability to solubilize wood components, whereas [BMIM]Cl inhibits the growth of various bacterial hosts useful for bioconversion. We previously isolated a 10% [BMIM]Cl-tolerant bacterium Bacillus amyloliquefaciens CMW1. Here we report novel mechanisms of tolerance to [BMIM]Cl in strain CMW1 and a novel major facilitator superfamily transporter coded by an ionic-liquid tolerance (ILT) gene. First, using CMW1 cells grown in the presence or absence of 10% [BMIM]Cl, whole-transcriptome analysis and differentially expressed gene analysis were performed. Probable mechanisms of tolerance to [BMIM]Cl include the uptake of osmoprotectants from the culture medium toward CMW1 cells and the export of [BMIM] cations that accumulated in CMW1 cells. The finding represents a first step in elucidation of the mechanisms of IL resistance in Gram-positive bacteria. Second, we conferred tolerance to 5% [BMIM]Cl on [BMIM]Cl-susceptible Brevibacillus choshinensis using ILT gene. This finding provides a notable basis for engineering IL-tolerant bacterial hosts that are applicable for the effective and sustainable production of industrially important chemicals.
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