Hot off the presses! Oct 01 Trends Plant Sci

The Oct 01 issue of the Trends Plant Sci is now up on Pubget (About Trends Plant Sci): if you're at a subscribing institution, just click the link in the latest link at the home page. (Note you'll only be able to get all the PDFs in the issue if your institution subscribes to Pubget.)

Latest Articles Include:

• Editorial Board
  - Trends Plant Sci 16(10):i (2011)
  
• RNA-based regulation in the plant circadian clock
  - Trends Plant Sci 16(10):517-523 (2011)
  The circadian clock is an endogenous, approximately 24-h timer that enables plants to anticipate daily changes in their environment and regulates a considerable fraction of the transcriptome. At the core of the circadian system is the oscillator, made up of interconnected feedback loops, involving transcriptional regulation of clock genes and post-translational modification of clock proteins. Recently, it has become clear that post-transcriptional events are also critical for shaping rhythmic mRNA and protein profiles. This review covers regulation at the RNA level of both the core clock and output genes in Arabidopsis (Arabidopsis thaliana), with comparisons with other model organisms. We discuss the role of splicing, mRNA decay and translational regulation as well as recent insights into rhythms of noncoding regulatory RNAs.
• Molecular aspects of defence priming
  - Trends Plant Sci 16(10):524-531 (2011)
  Plants can be primed for more rapid and robust activation of defence to biotic or abiotic stress. Priming follows perception of molecular patterns of microbes or plants, recognition of pathogen-derived effectors or colonisation by beneficial microbes. However the process can also be induced by treatment with some natural or synthetic compounds and wounding. The primed mobilization of defence is often associated with development of immunity and stress tolerance. Although the phenomenon has been known for decades, the molecular basis of priming is poorly understood. Here, I summarize recent progress made in unravelling molecular aspects of defence priming that is the accumulation of dormant mitogen-activated protein kinases, chromatin modifications and alterations of primary metabolism.
• Nutritious crops producing multiple carotenoids â€" a metabolic balancing act
  - Trends Plant Sci 16(10):532-540 (2011)
  Plants and microbes produce multiple carotenoid pigments with important nutritional roles in animals. By unraveling the basis of carotenoid biosynthesis it has become possible to modulate the key metabolic steps in plants and thus increase the nutritional value of staple crops, such as rice (Oryza sativa), maize (Zea mays) and potato (Solanum tuberosum). Multigene engineering has been used to modify three different metabolic pathways simultaneously, producing maize seeds with higher levels of carotenoids, folate and ascorbate. This strategy may allow the development of nutritionally enhanced staples providing adequate amounts of several unrelated nutrients. By focusing on different steps in the carotenoid biosynthesis pathway, it is also possible to generate plants with enhanced levels of several nutritionally-beneficial carotenoid molecules simultaneously.
• Competitive inhibition of transcription factors by small interfering peptides
  - Trends Plant Sci 16(10):541-549 (2011)
  Combinatorial assortment by dynamic dimer formation diversifies gene transcriptional specificities of transcription factors. A similar but biochemically distinct mechanism is competitive inhibition in which small proteins act as negative regulators by competitively forming nonfunctional heterodimers with specific transcription factors. The most extensively studied is the negative regulation of auxin response factors by AUXIN/INDOLE-3-ACETIC ACID repressors. Similarly, Arabidopsis thaliana (Arabidopsis) little zipper and mini finger proteins act as competitive inhibitors of target transcription factors. Competitive inhibitors are also generated by alternative splicing and controlled proteolytic processing. Because they provide a way of attenuating transcription factors we propose to call them small interfering peptides (siPEPs). The siPEP-mediated strategy could be applied to deactivate specific transcription factors in crop plants.
• Emerging roles of the chloroplast outer envelope membrane
  - Trends Plant Sci 16(10):550-557 (2011)
  The chloroplast is essential for the viability of plants. It is enclosed by a double-membrane envelope that originated from the outer and plasma membranes of a cyanobacterial endosymbiont. Chloroplast biogenesis depends on binary fission and import of nuclear-encoded proteins. Our understanding of the mechanisms and evolutionary origins of these processes has been greatly advanced by recent genetic and biochemical studies on envelope-localized multiprotein machines. Furthermore, the latest studies on outer envelope proteins have provided molecular insights into organelle movement and membrane lipid remodeling, activities that are vital for plant survival under diverse environmental conditions. Ongoing and future research on the chloroplast outer envelope should add to our knowledge of organelle biology and the evolution of eukaryotic cells.
• Plant protein-coding gene families: emerging bioinformatics approaches
  - Trends Plant Sci 16(10):558-567 (2011)
  Protein-coding gene families are sets of similar genes with a shared evolutionary origin and, generally, with similar biological functions. In plants, the size and role of gene families has been only partially addressed. However, suitable bioinformatics tools are being developed to cluster the enormous number of sequences currently available in databases. Specifically, comparative genomic databases promise to become powerful tools for gene family annotation in plant clades. In this review, I evaluate the data retrieved from various gene family databases, the ease with which they can be extracted and how useful the extracted information is.
• Gibberellin control of stamen development: a fertile field
  - Trends Plant Sci 16(10):568-578 (2011)
  Stamen development is governed by a conserved genetic pathway, within which the role of hormones has been the subject of considerable recent research. Our understanding of the involvement of gibberellin (GA) signalling in this developmental process is further advanced than for the other phytohormones, and here we review recent experimental results in rice (Oryza sativa) and Arabidopsis (Arabidopsis thaliana) that have provided insight into the timing and mechanisms of GA regulation of stamen development, identifying the tapetum and developing pollen as major targets. GA signalling governs both tapetum secretory functions and entry into programmed cell death via the GAMYB class of transcription factor, the targets of which integrate with the established genetic framework for the regulation of tapetum function at multiple hierarchical levels.