Editors' Choice

New Phytologist Editors' Choice March 2017

Tansley Medal winner and finalists

In this issue’s Editors' Choice we are pleased to feature the work of the Tansley Medal winner and finalists. The New Phytologist Tansley Medal is awarded annually to a scientist in the early stages of his or her career in recognition of an outstanding contribution to research in plant science. In 2016, the Tansley Medal was awarded to Etienne Laliberté of the University of Montreal, Canada.

Etienne Laliberté - New Phytologist Tansley Medal winner 2016

Etienne Laliberté of the University of Montreal, Canada.
Winner of the 2016 Tansley Medal.

This year's finalists were:

  • Marie Barberon, University of Lausanne, Lausanne, Switzerland.
  • Charles W. Melnyk, The Sainsbury Laboratory, Cambridge, UK.
  • Roberto Salguero-Gómez, University of Sheffield, UK.
  • Benjamin Schwessinger, Australian National University, Australia.

We encourage you to read the collection of Tansley insights in this issue, all of which were submitted as part of the 2016 Tansley Medal competition. We offer our warmest congratulations all of the finalists, and we look forward to following their future careers.

Barberon, M. 2017. The endodermis as a checkpoint for nutrients. New Phytologist 213: 1604–1610.
Laliberté E. 2017. Below-ground frontiers in trait-based plant ecology. New Phytologist 213: 1597–1603.
Melnyk, C W. 2017. Connecting the plant vasculature to friend or foe. New Phytologist 213: 1611–1617.
Salguero-Gómez , R. 2017. Applications of the fast–slow continuum and reproductive strategy framework of plant life histories. New Phytologist 213: 1618–1624
Schwessinger, B. 2017. Fundamental wheat stripe rust research in the 21st century. New Phytologist 213: 1625–1631

Listen to our interview with Etienne Laliberté:

Liam Dolan
University of Oxford, UK
Tansley review Editor, New Phytologist

New Phytologist Editors' Choice November 2016

Plant senescence

This latest New Phytologist Editors’ choice highlights a virtual issue on Plant senescence. Honorary Treasurer and former New Phytologist Editor Howard Thomas and Co-Editor Helen Ougham have compiled this collection that highlights a diverse field of enquiry which encompasses the full and broad scope of plant sciences, from molecular-level research to global studies (Thomas & Ougham, 2016).

The timing of this collection coincides with the 8th International Symposium on Plant Senescence which will take place in Jeju, Korea (31 October – 4 November 2016), and also comes when those of us in the Northern hemisphere are enjoying the changing of the seasons and the rich palette of fall colours.

Thomas & Ougham (2016) Figure 1

Figure 1 from Thomas & Ougham (2016): Leaves change colour as their lives end.

This collection also coincides happily with the award to Yoshinori Ohsumi of the Nobel Prize in Physiology or Medicine for his work in discovering mechanisms for autophagy. Autophagy, the process by which organelles or cytoplasmic components are maintained and repaired by dismantling and recycling damaged components, has been implicated in age-related changes to plant physiology and in plant pathology, and thus features highly in senescence research (Thomas, 2013). The process of autophagy was originally identified in mammalian and yeast cells, but much of Prof. Oshumi’s work in this area has been in plant sciences, including collaborations with New Phytologist Editors Ralph Panstruga and Ken Shirasu (Yoshimoto et al., 2009).

Yoshimoto K, Jikumaru Y, Kamiya Y, Kusano M, Consonni C, Panstruga P, Ohsumi Y, Shirasu K. 2009. Autophagy Negatively Regulates Cell Death by Controlling NPR1-Dependent Salicylic Acid Signaling during Senescence and the Innate Immune Response in ArabidopsisPlant Cell 21: 2914–2927.

Thomas H. 2013Senescence, ageing and death of the whole plantNew Phytologist 197: 696–711.

Thomas H, Ougham H. 2016Introduction to a Virtual Issue on plant senescenceNew Phytologist 212: 531–536.

Sarah Lennon, Managing Editor New Phytologist
Lancaster, United Kingdom

New Phytologist  Editors' Choice April 2016

The New Phytologist  Tansley Medal 2015

The New Phytologist  Tansley Medal is awarded annually to a scientist in the early stages of his or her career in recognition of an outstanding contribution to research in plant science. In 2015, the Tansley Medal was awarded to Alexander M. Jones of the Sainsbury Laboratory, Cambridge, UK.

A.M Jones

Alexander M. Jones (Sainsbury Laboratory, Cambridge, UK)
Winner of the 2015 Tansley Medal

In this issue’s Editors' Choice we are very proud to highlight the work and achievements of Alexander and his fellow finalists and we encourage you to read their Tansley insights, submitted as part of the 2015 Tansley Medal competition. We offer our warmest congratulations all of the finalists, and we look forward to following their future careers.

Anderson JT. 2016. Plant fitness in a rapidly changing world. New Phytologist  210: 81–87.
Crutsinger GM. 2016. A community genetics perspective: opportunities for the coming decade. New Phytologist  210: 65–70.
Jones AM. 2016a. A new look at stress: abscisic acid patterns and dynamics at high resolution. New Phytologist  210: 38–44.
Lozano-Duran R. 2016. Geminiviruses for biotechnology: the art of parasite taming. New Phytologist  210: 58–64.
Macho AP. 2016. Subversion of plant cellular functions by bacteria type-lll effectors: beyond suppression of immunity. New Phytologist  210: 51-57.
Pringle EG. 2016. Integrating plant carbon dynamics with mutualism ecology New Phytologist  210: 71-75
Rodriguez-Villalon A. 2016. Wiring a plant: genetic networks for phloem formation in Arabidopsis thaliana roots. New Phytologist 210: 45-50.
Zhong X. 2016 Comparative epigenomics: a powerful tool to understand the evolution of DNA methylation. New Phytologist  210: 76-80.

Liam Dolan, Tansley review Editor, New Phytologist
University of Oxford,
Oxford, UK

New Phytologist  Editors' Choice March 2016

Plant volatiles

In late January and early February 2016 researchers will come together to participate in the 2016 Gordon Research Conference on the Diversity of Targets, Effects and Applications of Plant Volatiles.

It is fitting, therefore, that we highlight not one article in this Editors' Choice, but a new collection of articles on the topic of plant volatiles. These articles have been brought together by New Phytologist Editor André Kessler to form our latest Virtual Special Issue. See Kessler (2016) for full details.

Over 1,700 volatile organic compounds (VOCs), from at least 90 plant families, have been identified to date. The reviews and research articles brought together in this collection explore not only the mechanisms of biosynthesis and physiology of plant VOCs, but also the ecological functions of plant VOCs and their role in mediating plant interactions with other organisms, from pollinators, herbivores and natural enemies of herbivores to other plants, as well as the effects of VOC emission induced by biotic stresses.

Figure 2 

Figure 2 from Kessler (2016). Flower of the Peruvian native wild tomato Solanum peruvianum  L. (Solanaceae) visited by a Colletes  sp. (Colletidae) bee. Solanum peruvianum  provides an example for ‘herbivory-mediated pollinator limitation’ (Kessler et al., 2011). Herbivore-induced changes in floral volatile organic compound emission can affect pollinator attraction and, in consequence, plant fitness. (Photo: André Kessler)

Kessler A. 2016. Introduction to a Virtual Special Issue on plant volatiles. New Phytologist  209: 1333–1337.
Kessler A, Halitschke R, Poveda K. 2011. Herbivory-mediated pollinator limitation: negative impacts of induced volatiles on plant-pollinator interactions. Ecology  92: 1769–1780.

Read the Virtual Special Issue on Plant volatiles.

Sarah Lennon, Managing Editor, New Phytologist
Lancaster, United Kingdom

New Phytologist  Editors' Choice January 2016

Ozone, VOCs, and pollinator attraction

In the latest issue of New Phytologist  Farré-Armengol et al.  report new research highlighting the fascinating finding that high concentrations of ozone in ambient air induces the degradation of floral volatile organic carbon compounds (VOCs), which in turn influences the behaviour of the pollinators attracted to the floral scents. In an accompanying commentary, Manuel Lerdau explores the history of research on pollination, VOC emissions from plants and chemical degradation in the atmosphere, and considers future directions in light of Farré-Armengol et al .’s findings.

Farré-Armengol and colleagues analysed the degradation of floral scent volatiles in Brassica nigra  flowers in response to ozone and the subsequent behaviour of the generalist pollinator Bombus terrestris.  They concluded that high ozone concentrations can reduce the distance over which floral VOCs can be detected by pollinators, and hat this can have a significant negative impact on the pollinators’ attraction to the plants in question.

Figure 7

Figure 7 from Farré-Armengol et al.  Pollinator visitation to artificial flowers for the behavioural tests comparing: (a) floral scent (distance 0 at 0 ppb O3) vs clean air (filtered air with no flower scent) (n  = 21); (b) floral scent (distance 3 at 120 ppb O3) vs clean air (filtered air with no flower scent) (n  = 24); (c) floral scent (distance 0 at 120 ppb O3) vs degraded floral scent (distance 3 at 120 ppb O3) (n  = 21). Asterisks indicate the level of significance of paired t-tests (*, P < 0.05). Error bars indicate standard error of the mean (SEM).

Farré-Armengol G, Peñuelas J, Li T, Yli-Pirilä P, Filella I, Llusia J, Blande JD. 2016. Ozone degrades floral scent and reduces pollinator attraction to flowers. New Phytologist  209: 152–160.
Lerdau M. 2016. Minding (and bridging) the gap between evolutionary ecology and atmospheric biogeochemistry in a study of plant pollinator behaviour. New Phytologist  209: 11–12.

David Ackerly, Editor, New Phytologist
University of California, Berkeley
Berkeley, CA, USA

New Phytologist  Editors' Choice December 2015

Photosynthetic bark

New Phytologist  has a rich history of publishing work on drought-induced forest mortality and stress, and this topic is more vital than ever as we see growing evidence of forest decline and tree mortality linked to global change associated droughts. In this issue of New Phytologist, Vandegehuchte et al. (pp. 998–1002) discuss the little-explored role of carbon fixation by woody tissue, and make a case for incorprating measurements of photosynthesis in woody tissues into drought stress experiments. This topic is explored further in the corresponding commentary by Cernusak & Cheesman (pp. 995-997) who highlight how this important feature of drought physiology of woody plants can pave the way for future research and investigation.

editors choice

Figure 1 from Cernusak & Cheesman. A depiction of stem recycling photosynthesis in a woody plant. (a) The stem anatomy; the stem contains living cells in the sapwood, vascular cambium, and bark. These living cells respire CO2, which, along with CO2 translocated into the stem segment by the transpiration stream, diffuses to the atmosphere when the stem is in the dark (b). When illuminated, however, a portion of the respired CO2 is captured and recycled by the photosynthetic cells in the bark cortex (c).

Vandegehuchte MW, Bloemen J, Vergeynst LL, Steppe K. 2015. Woody tissue photosynthesis in trees: salve on the wounds of drought? New Phytologist  208: 998–1002.
Cernusak LA, Cheesman AW. 2015. The benefits of recycling: how photosynthetic bark can increase drought tolerance. New Phytologist 208: 995–997.

Nathan G. McDowell, Editor, New Phytologist
 Los Alamos National Laboratory
Los Alamos, NM, USA

New Phytologist  Editors' Choice October 2015

Plant synthetic biology

In June 2012 the 4th New Phytologist Workshop on synthetic biology brought together scientists working in the highly interdisciplinary field of synthetic biology to discuss research across three key themes, including ‘Engineering principles and approaches in synthetic biology’; ‘Synthetic biology in microbes’; and ‘Synthetic biology in plants’. The presentations from this Workshop are freely available: https://www.newphytologist.org/workshops/view/5.

It is fitting, therefore, that we take this opportunity to highlight a cluster of articles published in the most recent issue of New Phytologist, which develop the themes discussed at the June 2012 Workshop.

First, a new Viewpoint article in the Forum section of the journal outlines the development of the first common standard for the assembly of DNA parts for plant synthetic biology. This work led by Dr Nicola Patron of the Sainsbury Laboratory, Norwich, UK, describes the development of a standard for Type IIS restriction endonuclease-mediated assembly, defining a common syntax of 12 fusion sites to enable the assembly of eukaryotic transcriptional units. This common syntax is the result of work by leaders of the international plant science and synthetic biology communities, including inventors, developers and adopters of Type IIS cloning methods.

editors choice

Figure 3 from Patron et al. (2015). Twelve fusion sites have been defined. These sites allow a multitude of standard parts to be generated. Standard parts comprise any portion of a gene cloned into a plasmid flanked by a convergent pair of BsaI recognition sequences. Parts can comprise the region between an adjacent pair of adjacent fusion sites. Alternatively, to reduce complexity or when a particular functional element is not required, parts can span multiple fusion sites (examples in pink boxes).

Also in the Forum, a Meeting Report by Ruth Carmichael and co-authors highlights the ERASynBio/OpenPlant summer school for early career researchers, held in September 2014. This meeting aimed to provide participants with an introduction to synthetic biology in plant systems, and it marks the second ERASynBio-funded summer school that brought together early career researchers for synthetic biology training and networking.

Finally, a Profile of New Phytologist  Editor and Trustee Anne Osbourne rounds off the cluster. Anne is a Project Leader at the John Innes Centre and Director of the Norwich Research Park Industrial Biotechnology and Bioenergy Alliance. She also co-organised the 2012 New Phytologist Workshop, and is a Co-Director of the OpenPlant Consortium, a collaborative initiative between the University of Cambridge, the John Innes Centre and The Sainsbury Laboratory in Norwich that is focused on the development of open technologies for plant synthetic biology.

Patron NJ, Orzaez D, Marillonnet S, Warzecha H, Matthewman C, Youles M, Raitskin O, Leveau A, Farré G, Rogers C. 2015. Standards for plant synthetic biology: a common syntax for exchange of DNA parts. New Phytologist  208: 13–19.
Carmichael RE, Boyce A, Matthewman C, Patron NJ. 2015. An introduction to synthetic biology in plant systems :ERASynBio/OpenPlant summer school for early career researchers, September 2014. New Phytologist  208: 20–22.
Osbourn A. 2015. Profile: Anne Osbourn. New Phytologist  208: 23–25.

Sarah Lennon, Managing Editor New Phytologist
Lancaster, United Kingdom

New Phytologist  Editors' Choice August 2015

´Selfie´ DNA: friend or foe

Plants and other organisms interact in a myriad of ways in terrestrial ecosystems and the basis of communication among and within species is a source of intense interest, from molecular to global scales. While we think of DNA as the code that provides the genetic information of all organisms, recent discoveries on the functions of fragmented extracellular DNA (eDNA) outside the cell have opened a new arena for our understanding of biotic interactions. In this issue of New Phytologist, the Editors' Choice is a perspective piece by Vereslogou and colleagues, which explores a provocative phenomenon observed in plant litter (Mazzeloni et al. 2015) on the role of self eDNA in inhibiting growth and seed germination of plants of the same species. The authors of the original research interpreted the observed reduction in growth to a toxic effect of the self eDNA –that is, that the self DNA (as opposed to eDNA from other species) acts to inhibit growth, which the organisms are able to recognize and distinguish from other non-self eDNA fragments.

Vereslogou and colleagues (and see Commentary by Duran-Flores & Heil, 2015) suggest another explanation, that is not mutually exclusive, which is that the self eDNA actually functions as a signalling molecule for other plants of the same species – that is, plants that release eDNA fragments generally do so as a function of stress – which means that these fragments could be seen as a new form of a damage-associated molecular pattern (DAMP). Rather than a toxic effect, these self eDNA fragments serve to identify a hostile environment for conspecific individuals – a way of communicating that the present environment may not be the most hospitable for germination and growth.

Whether self eDNA serves as a friendly warning or a toxic avenger has yet to be determined, and there is still much work that needs to be done to establish the generality of these patterns across organisms and ecosystems. What is most interesting for me is to see the intersection of disciplines bringing to light a new and interesting insight into the ways in which organisms interact and communicate in their natural environment.

  Conceptual diagram

Figure 1 from the paper (Vereslogou et al., 2015). Conceptual diagram highlighting established (terpenoids, Baldwin et al. (2006); mycelial networks, Barto et al., 2012) and prospective (self-DNA) signaling pathways for plant–plant communication. Self-DNA appears to possess a range of unique signaling properties that could explain its presence in plants. 

Baldwin IT, Halitschke R, Paschold A, von Dahl CC, Preston CA. 2006. Volatile signaling in plant–plant interactions: “Talking trees? in the genomics era. Science  311: 812–815.
Barto EK, Weidenhamer JD, Cipollini D, Rillig MC. 2012. Fungal superhighways: do common mycorrhizal networks enhance belowground communication? Trends in Plant Science  17: 633–637.
Duran-Flores D, Heil M. 2015. Growth inhibition by self-DNA: a phenomenon and its multiple explanations. New Phytologist  207: 482–485
Mazzoleni S, Cartenì F,Bonanomi G, Senatore M,Termolino P, Giannino F,Incerti G, Rietkerk M, Lanzotti V, Chiusano ML. 2015. Inhibitory effects of extracellular self-DNA: a general biological process? New Phytologist 206: 127–132.
Veresoglou SD, Aguilar-Trigueros CA, Mansour I, Rillig MC. 2015. Self-DNA: a blessing in disguise? New Phytologist  207: 488–490.

Amy T. Austin Editor, New Phytologist 
IFEVA, Consejo Nacional de Investigaciones Científicas y Técnicas, Universidad de Buenos Aires, Buenos Aires, Argentina and IIB-INTECH, Consejo Nacional de Investigaciones Científicas y Técnicas, Universidad Nacional de San Martín, Buenos Aires, Argentina

New Phytologist  Editors' Choice July 2015

Rain forest radiations in the Amazon

In this Special Issue of New Phytologist  on Plant Evolutionary Radiations, Koenen et al.  present compelling evidence for recent evolutionary radiations in rain forest mahoganies in the Amazon. The mahogany family (Meliaceae) comprises 700 species of deciduous and evergreen trees in seasonally dry and wet forests across the tropics. Koenen et al.  reconstruct a phylogeny for the family and estimate spatiotemporal diversification trajectories in one of the first studies to compare diversification patterns across lineages spanning dry and wet tropical forests. They show that the majority of mahogany species diversity in tropical rainforests is recent and the result of higher speciation rates compared to non-rainforest lineages.

While it is apparent that other species-rich Amazonian tree lineages also diversified rapidly in the late Miocene and Pliocene, this study provides much more convincing evidence that these rainforest clades, viewed in the context of a global analysis of the whole family, do constitute radiations subtended by species diversification rate increases. It is striking that these rain forest radiations are ecologically, structurally and functionally convergent and happened in the same place at the same time in different lineages. If we believe the age estimates in this study, most of the species in these radiations evolved during the Pleistocene, an idea that has been the focus of much debate surrounding Amazonian Pleistocene refuge theory, but which has not been demonstrated before in macroevolutionary studies of Amazonian trees.

Figure 2

Figure 2 from the paper (Koenen et al.)  Phylorate plot with branches colored by speciation rate (lineages/Myr) as indicated by the scale bar, representing a summary of the full post-burn-in Markov chain Monte Carlo (MCMC) sample of the Bayesian analysis of macro-evolutionary mixtures (BAMM) analysis. Red circles indicate the positions of regime shifts in the maximum a posteriori (MAP) configuration (the MAP configuration is also shown in the upper left panel of Supporting Information Fig. S6). Numbers beneath the shifts indicate the marginal probability of a shift occurring along that branch. The tree displayed here is the maximum clade credibility (MCC) tree of Scenario 2.

The evolution of tropical rain forest hyperdiversity remains poorly understood. On the one hand rain forests have been viewed as museums where diversity accumulated at a constant slow rate with low extinction throughout the Cenozoic. Others have suggested that most rain forest diversity is much more recent, invoking a recent cradle model to explain current hyperdiversity. What is significant and interesting about Koenen et al.’s  study is the model of high episodic species turnover they propose to explain their results. Under this new model rainforests can be viewed as museums of higher-level taxa and trait diversity that provided the template for recent radiations.

Koenen EJM, Pennington TD, Clarkson JJ, Chatrou LW. 2015. Recently evolved diversity and convergent radiations of rain forest mahoganies (Meliaceae) shed new light on the origins of rain forest hyperdiversity. New Phytologist  207: 327–339.

Colin Hughes, Reto Nyffeler and Peter Linder
Guest Editors, New Phytologist
University of Zurich, Switzerland

New Phytologist  Editors' Choice June 2015

Root biochemistry, root traits, and soil carbon – making the links

A large fraction of the carbon that is sequestered in soil is derived from fine roots, but traditional indices of root decomposition (e.g., carbon-to-nitrogen ratio) have failed to adequately reflect the importance of fine roots to soil carbon. Phenolic compounds exert a disproportionate influence on root decomposition and recalcitrance, and in the latest issue of New Phytologist Wang et al.  report on the linkage between macro-elemental and morphological traits of fine roots with the quantitative and qualitative profile of phenolic compounds.

Recognizing that fine roots cannot be treated as a homogenous carbon source, Wang et al. structured their investigation using the framework of variation of root traits within fine root architecture. They analyzed the seasonal dynamics of phenolic compounds in leaves and roots of Ardisia quinquegona, an important forest shrub species in South China and looked for correlations between phenolic content and a suite of root traits across root branching order. Free and bound phenols decreased with increasing root order, and seasonal variation was greater in lower order roots. Significantly, root traits such as specific root length and nitrogen content were decoupled from the phenolic profile, revealing the inadequacy of these more traditional indicators of carbon quality.

This paper is particularly noteworthy for making the critical links between detailed biochemical analyses, the higher order ecological implications of the phenolic profiles, and the value of the root trait framework to ecological modeling. Comprehensive and integrative perspectives such as this are needed for developing a predictive understanding of carbon, water, and nutrient cycling in terrestrial biosphere models.

Wang J-J, Tharayil N, Chow AT, Suseela V, Zeng H. 2015. Phenolic profile within the fine root branching orders of an evergreen species highlights a disconnect in root tissue quality predicted by elemental- and molecular-level carbon composition. New Phytologist 206: 1261–1273.

Richard Norby, EditorNew Phytologist
Oak Ridge, TN, USA

New Phytologist  Editors' Choice April 2015

Septoria leaf blotch disease in wheat

In the latest issue of New Phytologist a Rapid report by Lee et al.  describes recent insights into how the fungus that causes Septoria leaf blotch disease in wheat is able to hijack the host’s signalling machinery to its own advantage. As this fungus is a major foliar pathogen and is a significant threat to yield in most wheat growing regions the work has considerable biotechnological potential.

Septoria leaf blotch disease is caused by a hemibiotrophic pathogenic fungus Zymoseptoria tritici  (also known as Mycosphaerella graminicola  and Septoria tritici), and it is characterised by a long, symptomless fungal growth period in host cells that is followed by a rapid switch to a necrotrophic growth phase. The necrotrophic phase results in lesions that ultimately destroy the leaves of the plant. The mechanism by which the pathogen achieves the long symptomless growth phase in the host tissue is not clear although it is known that the transition to the necrotrophic phase is associated with global reprogramming of host transcription. In their paper, Lee et al.  identified a wheat homeodomain (PHD) protein, TaR1, that plays a crucial role in the transition from the symptomless to the necrotrophic growth of Septoria. The authors suggest that TaR1 contributes to this transition through its capacity to regulate gene activation at transcriptionally active chromatin.

When Lee et al.  investigated TaR1 expression they found that it is maximal during the latter stage of symptom-less infection and then drops off dramatically at the transition to the necrotrophic phase. Silencing TaR1 resulted in cell death symptoms appearing earlier in infected wheat leaves, as well as reduced production of picnidia and spores by the pathogen. These observations suggest that TaR1 suppresses the defence responses of the plant and influences the ability of Septoria to reproduce asexually in wheat. The authors conclude that TaR1 helps Septoria bypass the natural defences of the plant, and this mechanism could potentially be exploited in future to develop Septoria control measures.

Figure 2

Figure 2 from the paper (Lee et al.Triticum aestivum R1  expression increases on infection. SilencingTaR1  leads to earlier onset of symptoms and reduced spore production. (a) Real-time polymerase chain reaction (RT-PCR) data shows the expression pattern ofTaR1  in both Septoria infected (grey bars) and healthy (black bars) plants over 17 d of infection. Error bars, ± standard error (SE) of the mean of raw data. (b) RT-PCR data shows the expression of TaR1  is reduced in virus-induced gene silencing (VIGS) treated plants silenced by BSMV:TaR1_A and BSMV:TaR1_B, 14 d after Barley Stripe Mosaic Virus (BSMV) treatment, compared to BSMV:00 and wild-type (Mock). Expression in the wild-type sample is set to 1 and all expression levels are given in arbitrary units relative to this. Error bars, ± SE of the mean of raw data. (c) A single leaf of BSMV:TaR1_A silenced and BSMV:00 mock silenced wheat from 10 to 18 d post-infection with Zymoseptoria tritici  (left), or mock infection (right). Symptoms appear up to 2 d earlier in BSMV:TaR1_A silenced plants (day 13) compared to mock silenced (day 15), while no symptoms appear in either of the mock silenced plants. (d) Representative images showing the level of picnidia formation on mock silenced and TaR1 silenced leaves, 4 wk after infection with Z. tritici. (e) The number of picnidia produced on the leaves of TaR1 silenced plants shows about a two-fold reduction compared to mock silenced plants. Student's t -tests show a significant difference between the number of picnidia produced on the mock silenced plants and the TaR1_A (P value = 9.9 × 10−3) and TaR1_B (P = 5.2 × 10−3) silenced lines, but no difference between the two TaR1 silenced lines (P = 0.23). Error bars, ± SE of the mean of raw data. (f) Spore washes performed 4 wk after infection show a more than two-fold reduction in spores produced on TaR1  silenced plants. Student's t-tests show a significant difference between the number of spores produced in the mock silenced plants and the TaR1_A (P value = 1.4 × 10−32) and TaR1_B (P = 2.4 × 10−34) silenced lines, but no difference between the two TaR1 silenced lines (P = 0.49). Error bars, ± SE of the mean of raw data.

Lee, J, Orosa, B, Millyard, L, Edwards, M, Kanyuka, K, Gatehouse, A, Rudd, J, Hammond-Kosack, K, Pain, N, Sadanandom, A. 2015. Functional analysis of a Wheat Homeodomain protein, TaR1, reveals that host chromatin remodelling influences the dynamics of the switch to necrotrophic growth in the phytopathogenic fungus Zymoseptoria tritici. New Phytologist  206: 598–605.

Alistair Hetherington, Editor-in-Chief New Phytologist
Bristol, United Kingdom

Sarah Lennon, Managing Editor New Phytologist
Lancaster, United Kingdom

New Phytologist  Editors' Choice April 2015

Chemical mimicry and Aristolochia

An increasing number of deceptive pollination systems and their underlying complex pollinator attraction mechanisms have been identified in recent years. Through structural, visual and scent cues deceptive plants mimic the presence of mating partners, oviposition substrates, and food to attract their respective pollinators, with an often remarkable specificity. The genus Aristlochia  L. represents a prime example because seemingly all species in this genus deceive their pollinators. In the latest issue of New Phytologist Oelschlägel et al.  discuss interactions between the Mediterranean Aristolochia rotunda and its pollinators, and describe an extraordinary pollination system, kleptomyiophily, where the plant releases compounds that mimic those emitted from recently-killed insects in order to attract kleptoparasites.

The main pollinators of A. rotunda  are female Chloropidae, kleptoparasitic insects that feed on secretions of true bugs (Miridae). Oelschlägel et al. note that Aristolochia flowers release a scent which mimics that of recently killed mirids – a scent which entices chloropids to visit the plant in search for a putative food source. Aristolochia  thus ‘deceive’ their pollinators by promising the reward of a food source that the plant does not fulfil.

Figure 1

Figure 1 from the paper (Oelschlägel et al.). Actors involved in the newly discovered mimicry system and bioassay setup. (a) Flower of Aristolochia rotunda  with a Trachysiphonella ruficeps  individual at the margin of the flower tube. (b) Magnification of panel (a). (c) T. ruficeps  pollinator collected from an A. rotunda  flower in the female stage, carrying Aristolochia  pollen on the head and thorax. (d) Flytrap used for bioassays. (e) T. ruficeps  pollinator sticking to insect glue of a trap loaded with Mix ‘Aristolochia-Miridae’. (f) T. ruficeps  individuals on a freshly killed Capsus ater. The fly in the upper part of the picture is feeding on C. ater  secretions.

Oelschlägel B, Nuss M, von Tschirnhaus M, Pätzold C, Neinhuis C, Dötterl S, Wanke S. 2015. The betrayed thief – the extraordinary strategy of Aristolochia rotunda  to deceive its pollinators. New Phytologist  206: 342–351.

Andre Kessler, Editor New Phytologist
Cornell University, Ithaca, NY, USA

New Phytologist  Editors' Choice March 2015

Mycorrhizal fungal community composition: host identity and ecosystem development

When the new—soil-less—ground becomes available after glacier retraction or volcanic eruptions, organisms start to arrive and soil starts to develop through the complex interplay of biota and abiota. How the vegetation and physicochemical properties of soils change during this process (primary succession) is relatively well understood, however, knowledge about how plant-related microbes, so essential for soil formation and plant life, change during succession, is still very fragmentary. This is not because there is no interest. Rather, the strongest limitation is that there are few study systems on the Earth where natural succession can be investigated without confounding factors such as altitudinal and related climatic, or other changes, alongside the changing age of ecosystems. Franz Josef Glacier in New Zealand is one of the few such sites, having freshly deglaciated lands, progressing mid-successional and climax ecosystems and retrogressing habitats, spanning site ages from 5 to 120 000 years since deglaciation.

This paper by Martinez-Garcia and colleagues embarks on an exciting journey towards understanding how the assemblages of plant root associating arbuscular mycorrhizal (AM) fungi change during primary succession. They find that some AM fungi prevail during early succession, others are found in well-developed ecosystems and a third group of fungi can be found in the retrogressing ecosystems; some fungi occur throughout all stages. Major shifts, rather than incremental changes of the fungal communities, occur between the ecosystem stages. The identity of the plant host was demonstrated to be the major factor determining the suite of root-associating AM fungi.

Figure 2

Figure 2 from the paper (Martinez-Garcia et al.). Proportion of pyrosequencing operational taxonomic units (OTUs) along the Franz Josef soil chronosequence that have a significant response (P 0.05) to ecosystem age: (a) linear or log-linear decreases (early OTUs), (b) quadratic (mature OTUs) and (c) linear or log-linear increases (retrogression OTUs). Model selection based on lowest Akaike Information Criterion (AIC) value.

This study is the first one to look at the AM fungal communities over such a long gradient of ecosystem development, and provides the very first data of AM fungi from retrogressive habitats. As an exemplary ground-breaking study, this paper opens more questions than it answers, indicative of the exciting discoveries ahead. What are the properties (traits) of AM fungi making them abundant in differently aged vegetation? What governs the AM fungal–plant-host relationships? Which AM fungi are needed to revegetate a barren ground or to restore a well-functioning self-sustaining mature ecosystem? These are just a few of the questions that will be tackled by the scientific community, thanks to this paper, with fresh rigour and inspiration.

Martínez-García, LB, Richardson, SJ, Tylianakis, JM, Peltzer, DA, Dickie, IA. 2015. Host identity is a dominant driver of mycorrhizal fungal community composition during ecosystem development . New Phytologist  205: 1565–1576.

Maarja Öpik, Editor New Phytologist
University of Tartu, Estonia

New Phytologist  Editors' Choice February 2015

The New Phytologist  Tansley Medal 2014

In this issue’s Editors' Choice we are very proud to highlight and acknowledge the achievements of the winner and finalists of the 2014 New Phytologist Tansley Medal competition. The 2014 Tansley Medal was awarded to William Anderegg of Princeton University for his Minireview titled ‘Spatial and temporal variation in plant hydraulic traits and their relevance for climate change impacts on vegetation’. More information on William and the other finalists can be found in the Editorial by Lennon and Dolan (2014).

William R. L. Anderegg, Princeton University

Image above: The 2014 Tansley Medal winner William R. L. Anderegg, Princeton University, NJ, USA.

The Minireviews published in the latest issue of New Phytologist  showcase the work of seven outstanding scientists, each of whom are in the early stage of their career, and they also encompass all four sections of New Phytologist : Physiology & Development; Environment; Interaction; and Evolution. This outstanding group of articles underscores the excellence of the 2014 winner and finalists, and we offer our heartfelt congratulations to them all.

Anderegg WRL. 2015. Spatial and temporal variation in plant hydraulic traits and their relevance for climate change impacts on vegetation. New Phytologist  205: 1008–1014.
Campbell SA. 2015. Ecological mechanisms for the coevolution of mating systems and defence. New Phytologist  205: 1047–1053.
De Frenne P. 2015. Innovative empirical approaches for inferring climate-warming impacts on plants in remote areas. New Phytologist  205: 1015–1021.
Hollister JD. 2015. Polyploidy: adaptation to the genomic environment. New Phytologist  205: 1034–1039.
Lennon S, Dolan L. 2015. The New Phytologist Tansley Medal 2014. New Phytologist  205: 951–952.
Nakamura M. 2015. Microtubule nucleating and severing enzymes for modifying microtubule array organization and cell morphogenesis in response to environmental cues. New Phytologist  205: 1022–1027.
Saunders DGO. 2015. Hitchhiker's guide to multi-dimensional plant pathology. New Phytologist  205: 1028–1033.
Sloan DB. 2015. Using plants to elucidate the mechanisms of cytonuclear co-evolution. New Phytologist  205: 1040–1046.

Sarah Lennon, Managing Editor New Phytologist
Lancaster, United Kingdom

New Phytologist  Editors' Choice January 2015

Transcriptional targeting branches out

Genome-wide approaches are dramatically expanding our understanding of the breadth of transcription factor target gene repertoires. While these techniques have primarily been applied to Arabidopsis, the addition of other taxa has the potential to provide critical insight into the evolution of transcriptional networks. Recent work in Andrew Groover’s lab has made an important contribution to this effort in identifying the genome-wide targets of the KNOX homeodomain protein ARBORKNOX1 (ARK1) in Populus. This protein is of special interest because it has been shown to play a major role in patterning and promoting activity of the vascular cambium. Of course, orthologs of ARK1, including the Arabidopsis gene SHOOTMERISTEMLESS (STM), are also broadly responsible for maintaining the peripheral zone of shoot apical meristems in many taxa. It, therefore, appears that the meristematic KNOX genetic module has been activated in the stem to promote a woody habit in Populus. This co-option event is likely to have been repeated many times independently in different phylogenetic lineages in association with the evolution of extensive secondary growth.

Aspen (Populus tremuloides) Tree

Image showing an aspen (Populus tremuloides ) tree. Photo credit: Gayle Dupper, USDA Forest Service.

The current Populus dataset, derived from vascular samples, has revealed a number of interesting patterns. First, within the context of the recent Populus  genome duplication, the authors find that ARK1 targets are significantly enriched among retained paralogs, possibly suggesting that developmentally important loci have been preferentially retained following genome duplication. Across a much wider phylogenetic scale, the authors also compare their set of ARK1 targets to those identified from maize reproductive meristems for the KNOTTED1 (KN1) ortholog. Although this comparison is complicated by several intervening genome duplication events, it appears that there are thousands of commonly targeted homologs between ARK1 in Populus  and KN1 in maize, possibly suggesting deep conservation of the target repertoire of ARK1 orthologs. Moreover, this could indicate that the activation of meristematic growth in the context of the vascular cambium shares considerable similarity to the promotion of meristematic growth at the shoot apex. In order to fully explore these kinds of questions, we will need comparable sampling from apical meristems in Populus  as well as additional, phylogenetically distributed taxa.

Liu L, Zinkgraf M, Petzold HE, Beers EP, Filkov V, Groover A. 2015. The Populus  ARBORKNOX1 homeodomain transcription factor regulates woody growth through binding to evolutionary conserved target genes of diverse function. New Phytologist  205: 682–694.

Elena Kramer, Editor New Phytologist
Harvard University, Cambridge, MA, USA

New Phytologist  Editors' Choice January 2015

Kin recognition in plants Many animals are able to recognise kin from strangers. This ability has allowed them to develop a diverse range of cooperative behaviours. By comparison, the occurrence of kin recognition in plants is less well studied. A recent report by Crepy and Casal however has demonstrated that kin recognition contributes to increasing fitness in the model flowering plant Arabidopsis thaliana. Shading between neighbouring plants can comprise their growth by reducing the light available for photosynthesis. In their study, Crepy and Casal found that kin plants were able to recognise their neighbours and promote light sharing by horizontally re-orienting their leaves so as to minimise shading between plants. Consequently, kin plants showed improved productivity, yielding more seed compared to non-kin plants or plants comprised in their ability to re-orientate their leaves (Fig. 2b).

Fig. 2b

Figure 2b from the article (Crepy and Casal). Representative leaf (false coloured) changing its growth direction in a row formed by kin neighbours: originally oriented towards its neighbour (day 5), the leaf then grows towards the empty space out of the row of neighbours (day 7).

These new findings therefore highlight a mutual benefit for cooperative interactions between kin plants. The authors also go on to show that light cues perceived by specific photoreceptor proteins play a key role in re-orientating the leaves between neighbouring kin plants. To date, studies on plant kin recognition have largely centred on belowground interactions between roots. The work by Crepy and Casal now clearly demonstrates the contribution of aboveground interactions in mediating kin recognition in Arabidopsis. Taken together, these findings provide further evidence to support the existence of kin recognition in plants and should have important implications in improving productivity in agriculture.

Crepy MA, Casal JJ. 2015. Photoreceptor-mediated kin recognition in plants. New Phytologist  205: 329–338.

John Christie, Editor New Phytologist
University of Glasgow, Glasgow, UK

See also the commentary on this article by Harish P. Bais entitled Shredding light on kin recognition in plants.

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