Plant, Cell & Environment

Cooke et al. review recent advances in bud dormancy research from both a physiological and molecular perspective. Bud dormancy is dynamic rather than a single state, with interactions between intrinsic and environmental signaling cues altering the depth of dormancy. The review discusses our state of knowledge of molecular mechanisms implicated in bud formation, growth cessation and dormancy acquisition, including the circadian clock, FT/CO regulatory module, epigenetics, central metabolism, and cell-to-cell communication. Recent quantitative and population genetics studies that aim to discover genes underlying genetic variation in dormancy are also highlighted.

The physiological significance of plant circadian clocks in natural environments is discussed. Robust rhythms under flucutuating natural enviromnents is critically compared with sustainable circadian rhythms under laboratory constant conditions in this review.

Recent studies have identified FT-like proteins as major regulatory factors in a wide range of developmental processes including the regulation of flowering time, fruit set, vegetative growth, stomatal control and tuberization. These multifaceted roles of FT-like proteins appear to have resulted from extensive gene duplication events, which occurred independently in nearly all modern angiosperm lineages, followed by sub- or neo-functionalization. This review assesses the plethora of roles that FT-like genes have aquired during evolution and their implications in plant diversity, adaptation and domestication.

Mitochondrial nitrogen (N) metabolism is best understood in the context of supplying C skeletons for N incorporation; however, it is now apparent that mitochondria are engaged in many other processes or pathways. The aim of our review was to emphasize central role of mitochondria in anabolic, catabolic and signaling pathways of N metabolism. We discuss the changes in mitochondrial N metabolism under different environmental conditions or developmental stages of plants.

Seed dormancy is an important component of plant fitness that causes a delay of germination until the arrival of a favourable growth season. This review gives an overview of our present understanding of the mechanisms that control seed dormancy at the molecular level. The regulators involved in the induction and release of dormancy, the influence of environmental factors and the conservation of seed dormancy mechanisms between plant species are discussed, as well as expected future directions in seed dormancy research.

Recently, several studies have demonstrated how correlated gene expression patterns can be compared between species using gene expression data and homology. The incorporation of detailed functional annotations as well as experimental data provides a means to identify conserved gene modules and translate biological knowledge between organisms. In this review, we describe the different steps required to systematically compare expression data across plants species and discuss some future applications of comparative transcriptomics.

Wheat provides 20% of the calories to the world's population so the future productivity of wheat will arguably have more influence on global food security than that of any other crop. The Wheat Yield Consortium brings expertise in photosynthesis, crop adaptation, and genetics to a common breeding platform thereby focusing research on combining the traits most likely to show impact in an agronomic context. Theory suggest RUE of wheat could be increased ∼50% using a combination of transgenic and non transgenic approaches, but to maximize yield expression will also require dynamic optimization of source: sink so that dry matter partitioning to reproductive structures is not at the cost of physiological and structural integrity of the crop canopy. A range of conventional and innovative breeding approaches are described, as well as the need for complementary work in crop management and networking to ensure that the benefits of new cultivars are maximized.

Plants have tremendous capacity to acclimate to environmental condition. Therefore, analysis solely of plants grown under constant conditions may give partial or misleading indications of their responses to the fluctuating natural conditions in which they evolved. Metabolic profiling offers a powerful way to understand the metabolic changes at global level in plants under ambient and stressful condition and we have studied systematic differences in metabolite levels between Arabidopsis thaliana grown under field and controlled conditions. Numerous compounds showed light-intensity dependent accumulation under controlled conditions, including many sugars and sugar derivatives. When plants were shifted to field conditions, levels of many identified metabolites (mainly amino acids, sugars and TCA cycle intermediates) rose after 2 h and peaked after 73 h, indicative of a ‘biphasic response’ and ‘circadian’ effects

Iron toxicity is a major nutritional disorder affecting rice production but mechanisms involved in plant resistance are not clearly elucidated. In this study, we propose for the first time, to the best of our knowledge, a transcriptomic analysis of rice under iron stress. In order to investigate the effect on both short- and long-term, micro-array gene expression profiling was performed on rice seedlings after 3 days and 3 weeks of iron exposure. Our results revealed a strong difference in the gene regulation after 3 days and 3 weeks of iron exposure. In order to decipher the metabolic consequences of the recorded changes, we also performed a targeted metabolite and physiological approach related to specific identified pathways affected by iron exposure and highlight the links between gene expression and the underlying physiological response of rice to ferrous iron toxicity.

Arabidopsis thaliana is a geographically widely spread species consisting of local accessions that may be adaptated to their habitat climate. Here we present evidence for geographical clines in the leaf freezing tolerance of 54 different accessions. Measurements of Glc, Fru, Suc, Raf and Pro contents and of the xpression levels of 14 cold induced genes shed new light on the molecular determinants of plant freezing tolerance and cold acclimation and their geographical dependence.