The Petunia tra1 gene controls cell elongation and plant development, and mediates responses to cytokinins

The molecular control of cell elongation, one of the basic processes of plant morphogenesis, is still largely not understood. This paper describes a Petunia hybrida mutant of dumpy phenotype, trapu, which identifies tra1, a gene required for cell elongation and mediating responses to applied cytokinin. This mutant displayed an extreme reduction in length, due to a single recessive mutation which was expressed in every part of the plant and during the entire life of the plant, including the mature embryo. The mutant was unable to flower. The mutant roots, as well as the leafy organs, were short and thick, and the root elongation zone, hypocotyl and petioles were absent. The mutant plantlets responded neither to applied auxin nor to gibberellin, indicating that this phenotype was not caused by a deprivation of these phytohormones. However, unlike the wildtype, the mutant growth was stimulated by applied cytokinin, even though its morphology remained abnormal. A histological study revealed the presence of all tissue types in normal positions, including root hairs and vascular bundles. The mutant's cells were rounder in every tissue. Both shoot and root meristems were disorganized, without consistent cell shape and size. The regular cell files, which are typical of a normal root apex organization, were totally absent in the mutant root apex. Indirect immunofluorescence of α-tubulin on root apices showed the cortical microtubules in the mutant cells to be unable to form the parallel arrays in elongating cells and the preprophase band in dividing cells. This default resulted in the prevention of unidirectional cell elongation and formation of regular cell files, thus causing the trapu phenotype. This paper discusses the similarities and differences of trapu to the Arabidopsis mutants, fass and ton, trapu confirming that the establishment of plant body pattern and differentiation can be dissociated from cell elongation.     

Lactobacillus rhamnosus GG-supplemented formula expands butyrate-producing bacterial strains in food allergic infants

Dietary intervention with extensively hydrolyzed casein formula supplemented with Lactobacillus rhamnosus GG (EHCF+LGG) accelerates tolerance acquisition in infants with cow''s milk allergy (CMA). We examined whether this effect is attributable, at least in part, to an influence on the gut microbiota. Fecal samples from healthy controls (n=20) and from CMA infants (n=19) before and after treatment with EHCF with (n=12) and without (n=7) supplementation with LGG were compared by 16S rRNA-based operational taxonomic unit clustering and oligotyping. Differential feature selection and generalized linear model fitting revealed that the CMA infants have a diverse gut microbial community structure dominated by Lachnospiraceae (20.5±9.7%) and Ruminococcaceae (16.2±9.1%). Blautia, Roseburia and Coprococcus were significantly enriched following treatment with EHCF and LGG, but only one genus, Oscillospira, was significantly different between infants that became tolerant and those that remained allergic. However, most tolerant infants showed a significant increase in fecal butyrate levels, and those taxa that were significantly enriched in these samples, Blautia and Roseburia, exhibited specific strain-level demarcations between tolerant and allergic infants. Our data suggest that EHCF+LGG promotes tolerance in infants with CMA, in part, by influencing the strain-level bacterial community structure of the infant gut.     

Aerobic growth and respiration of a delta-aminolevulinic acid synthase (hemA) mutant of Bradyrhizobium japonicum.

Oxygen-dependent growth of the Bradyrhizobium japonicum hemA mutant MLG1 (M.L. Guerinot and B.K. Chelm, Proc. Natl. Acad. Sci. USA 83:1837-1841, 1986) was demonstrated in cultured cells in the absence of exogenous delta-aminolevulinic acid (ALA), but growth of analogous mutants of Rhizobium meliloti or of Escherichia coli was not observed unless ALA was added to the yeast extract-containing media. No heme could be detected in extracts of strain MLG1 cells as measured by the absorption or by the peroxidase activity of the heme moiety, but the rates of growth and endogenous respiration of the mutant were essentially identical to those found in the parent strain. A role for ALA in the viability of strain MLG1 could not be ruled out since the ALA analog levulinic acid inhibited growth, but neither ALA synthase nor glutamate-dependent ALA synthesis activity was found in the mutant. The data show that the cytochromes normally discerned in wild-type B. japonicum cultured cells by absorption spectroscopy are not essential for aerobic growth or respiration.     

Effect of different photoperiodic regimes on growth, flowering and essential oil in Mentha species

Three major cultivated Mentha spp. (M. arvensis, M. citrata and M. cardiaca) were grown under short-days, normal-days or long-days for 60 cycles. Subsequent to photoperiodic treatment, the plants were assessed for growth behaviour, essential oil content, oil composition and essential oil biosynthesis. The species grew better under long-day conditions. The long-day treatment resulted in flowering in M. citrata, which normally does not flower under our conditions. The oil concentration and biogenesis was maximal in short-day plants. The photoperiodic treatment also affected the oil composition. The observations are discussed in relation to physiology of the oil biogenesis.     

Regulation of essential oil production in plants

This review provides a summary of the physiological dynamics andregulation of essential oil production, from the literature and availableinformation on diverse volatile oil crops. Essential oil production is highlyintegrated with the physiology of the whole plant and so depends on themetabolic state and preset developmental differentiation programme of thesynthesising tissue. Essential oil productivity is ecophysiologically andenvironmentally friendly. These and other aspects of the modulation ofessentialoil production are presented, along with a brief outline of the current conceptof the relevant biosynthetic mechanisms.     

Genome Sequence of Acinetobacter sp. Strain HA, Isolated from the Gut of the Polyphagous Insect Pest Helicoverpa armigera

In this study, Acinetobacter sp. strain HA was isolated from the midgut of a fifth-instar larva of Helicoverpa armigera. Here, we report the draft genome sequence (3,125,085 bp) of this strain that consists of 102 contigs, 2,911 predicted coding sequences, and a G+C content of 41%.