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Proprioception: sensing of the posture, shape and relative orientation of body parts

Are Plants Self-Aware?

No, I’m NOT referring to plant self-awareness as it relates to plant “consciousness”. (If you’re interested in such metaphysical aspects of plant physiology, please see here, for example.)

What I’m referring to is the notion that plants are physically self-aware. In other words, can a plant perceive the configuration of its own body?

In zoology this concept is sometimes referred to as “proprioception”.

The term “proprioception” was first used over 100 years ago by neurophysiologist Charles Scott Sherrington to define an animal’s sense of the relative position of the parts of its body.

Close your eyes. Now touch your nose with the tip of a finger. That’s an example of an ability made possible by proprioception.

In animals, mechanisms of proprioception are complex, the result of multiple inputs, both internal and external, all integrated and interpreted by the brain.

In the past few years, some plant scientists have suggested that proprioception also occurs in plants and, moreover, significantly affects plant development.

Shape-Sensing in Plants?

As far as I know, a paper published in 2013 (see Ref. 1 below) may have been the first to propose that proprioception is a significant factor in plant development. Briefly, the authors analyzed shoot growth in response to gravity and concluded that the observed curvature was a result not only of shoot gravity-sensing but also localized self-sensing of the shoot shape.

“Localized” may be the key word with regard to invoking proprioception in plants, and also how this concept differs in plants compared to proprioception animals.

On using the term “proprioception” with regard to plant development: “The overall picture is still rudimentary, but it bears some similarity to animals, with two types of proprioception. The first is a basic proprioception that allows for shape and growth activity control in the meristems and growth zones. Proprioceptive capacities are shared by all cells. In growing organs at later stages (e.g. stem, roots), a second type of proprioception may involve more specialized cells and cross-talk with other sensory specialized cells (e.g. the statocytes involved in gravitropic sensing) to achieve proper posture control and shape resilience to the mechanical hazards of the outer world…” (from Ref. 2 below)

Seems to me that what they’re saying here isn’t really new; they’re just trying to appropriate an animal physiological concept that relates to the whole organism and to apply it to plants at the cellular level.

That plant growth and form are the result of both internal (hormones, mechanical) and external (gravity, light, wind) factors have been known for decades (centuries?). Heck, even I had a post on the internal, mechanical affects on plant development in 2012: How Stress Shapes Plants.

Thus, appropriating the term “proprioception” from zoology and trying to apply it to plants may be a bit too much of a stretch. (Please see here for my rant regarding why I think we shouldn’t, in general, try to zoomorphize plants.) Would using the concept of automorphogenesis be more appropriate?

Anyway, what’s new and exciting now, however, is the computational and molecular research being conducted on how internal mechanical forces may affect differential gene expression, which, ultimately, determines plant development.

But back to the question: Are Plants Self-Aware?….

Do Plants “Know” How Big They Are?

One way plants may be able to determine their relative size is by “node counting”. That is, the more nodes (stem buds/leaves) the plant has, the bigger (more productive) it is. (For all you scholars out there, an exhaustive review of “node counting” can be found here.)

A plant may also gauge its size by how far the shoot apical meristem (SAM) is from the roots. Or a plant may determine its overall size by how big a root system it has. There is scientific evidence for all of these possibilities. However, the key to all of them is that the nodes, the roots, or both produce chemical signals (likely one or more of the common plant hormones) that travel via the phloem to the SAM.

Bottom Line: Are plants self-aware, physically speaking? At the whole plant level, I think not. Certainly, not like animals are. Active areas of plant growth and development may be affected by local, physical factors and also by plant hormones originating from distal parts of the plant. But lacking a central processing unit, i.e., brain, plants don’t really have a way to integrate multiple inputs to create an awareness of a single, unified whole shape.

References

1. Bastien, R., T. Bohr, B. Moulia and S. Douady (2013) “Unifying model of shoot gravitropism reveals proprioception as a central feature of posture control in plants.” PNAS, Vol. 110, pp. 755–760. doi: 10.1073/pnas.1214301109 (Full Text)

2. Hamant, O. and B. Moulia (2016) “How do plants read their own shapes?” New Phytologist, Vol. 212, pp. 333–337. (Full Text)

3. Chelakkot, R. and L. Mahadevan (2017) “On the growth and form of shoots.” Journal of the Royal Society Interface, 2017 14 20170001; DOI: 10.1098/rsif.2017.0001. Published 22 March 2017. (Full Text – PDF)

“The Shape I’m In” by The Band

The final stop on our “Selfish Plant” tour = Selfish Genes in Plants

HowPlantsWork © 2008-2017 All Rights Reserved.

When No Really Means No (In Plants)

When it comes to sexual reproduction, nearly half of all flowering plant species are self-incompatible.

That is, the pollen (male parts of flowers) produced by an individual plant is somehow recognized by the plant and rendered ineffectual in self-fertilizing the ovules (female parts of flowers).

This prevention of self-fertilization promotes outcrossing and allogamy and, thus, increased genetic diversity. Self-incompatibility (SI) “…is one of the most important means of preventing inbreeding and promoting the generation of new genotypes in plants, and it is considered as one of the causes for the spread and success of angiosperms on the earth. (from Wikipedia)

Considering the above, I suppose you might say that SI is not really an example of the “selfish” plant… just the opposite.

But, in order for this sexual self-incompatibility to work, the plant must be able to somehow discern its own pollen from that of other plants. In other words, here we have yet another example of plants being able to recognize “self” from “non-self”.

In this case of SI, however, the plant rejects “self” pollen, but not “non-self” pollen.

When I was teaching this subject in class at university (in a former life), the students (who were still awake) would typically have three questions: (1) How do SI plants tell “self” from “non-self” pollen? (2) How do they “reject” the “self” pollen?, and (3) How did SI evolve in flowering plants?

Well, I’ll try to briefly answer these questions as follows:

  • (1) Pollen grains from SI plants have very specific protein “keys” on their surfaces that precisely fit only into “locks” on the surface of the stigmas of flowers from the same plant. Thus, when a “self” pollen grain lands on the stigma’s surface, the rejection mechanism is “unlocked” (activated). A “non-self” pollen grain does not have a matching “key” on its surface, so the rejection mechanism remains “locked” (inactive).
  • (2) In general, the rejection mechanism usually involves the biochemical inhibition of pollen germination by the stigma.
  • (3) “…different molecular mechanisms for avoiding self-breeding have evolved at least 35 times in angiosperm history.” (from Ref. 1 below) Because of this, the evolution of SI in flowering plants is currently unclear, although some (e.g., see Ref. 2 below) think that SI may be related to non-self rejection mechanisms (see previous post).
  • Please Note: The nature, mechanisms, and evolution of self-incompatibility (SI) in plants are quite complex. Rather than delve deeper into these subjects here, I’ll refer you to two of the best summaries I’ve found online, namely, Wikipedia and here.

    Since SI may be considered as a sort of plant kin recognition, in this case to discourage inbreeding, are there other examples of kin recognition in plants?

    Plant Nepotism?

    It’s well-know that kin recognition exists in animals, often resulting in both increased competition toward strangers and reduced interference (increased cooperation) toward kin.

    In 2007, a paper (Ref. 3 below) was published reporting that “…plants grown alongside unrelated neighbours are more competitive than those growing with their siblings….” (from Nature News), which (seems to me at least) sort of got the subject of plant kin recognition taken more seriously among plant scientists.

    Of course, one of the main questions regarding kin recognition in plants is how exactly the plants are able to discern “kin” from “non-kin”.

    The most popular theory appears to involve specific compounds in root exudates, but other theories have emerged including root electrical signals and also the quality of reflected light (Ref. 4 below) from adjacent plants above ground.

    Please see Ref. 5 below for a good review of this interesting subject.

    References

    1. Fujii, S., K-I. Kubo and S. Takayama (2016) “Non-self- and self-recognition models in plant
    self-incompatibility.” Nature Plants, 6;2(9):16130. doi: 10.1038/nplants.2016.130. (Abstract)

    2. Kear, P. J. and B. McClure (2012) “How did flowering plants learn to avoid blind date mistakes? Self-incompatibility in plants and comparisons with nonself rejection in the immune response.” Advances in Experimental Medicine and Biology, Vol.738, pp.108-123. doi: 10.1007/978-1-4614-1680-7_7. (Abstract)

    3. Dudley, S. A. and A. L. File (2007) “Kin recognition in an annual plant.” Biology Letters, Vol. 3, pp. 435-438; doi: 10.1098/rsbl.2007.0232. (Full Text)

    4. Crepy, M. A. And J. J. Casal (2015) “Photoreceptor-mediated kin recognition in plants.” New Phytologist, Vol. 205, pp. 329-338. (Full Text – PDF)

    5. Depuydt, S. (2014) “Arguments for and against self and non-self root recognition in plants.” Frontiers in Plant Science, 5:614. doi: 10.3389/fpls.2014.00614 (Full Text)

    For Next time:
    The Self-Aware Plant?

    HowPlantsWork © 2008-2017 All Rights Reserved.

    Dandelion Time….Again

    A recent story about how some of our Washington state lawmakers hate the sight of dandelions reminded me that it’s time for an encore of this post. Hope you enjoy it….again?

    Dandelions – Much Maligned.

    Some people become upset when they see dandelions (please see here, for example).

    Few plants generate such annoyance among suburban homeowners with immaculate lawnscapes (and even some Washington state legislators) as the common dandelion. (In North America, they are most likely Taraxacum officinale).

    What Do Suburban Lawns and the Vietnam War Have in Common?

    Answer: The herbicide 2,4-D.

    You may be familiar with this herbicide as an active ingredient in “Weed ‘n Feed®”, “Weed B Gon MAX®”, Turf Builder® With Weed Control”, etc..

    During the Vietnam War, it was an active ingredient in Agent Orange.

    On lawns it’s used to kill the dandelions, but NOT the grass. (Find out how it does this below).

    In the Vietnam War the U.S. military used it to defoliate the trees (so that they could more easily spot the Viet Cong).

    You’re likely familiar with the term “Agent Orange” because of the controversy regarding the tragic health problems it caused to U. S. soldiers. (For current info re. this issue see here).

    The serious health issues to both Americans and Vietnamese caused by Agent Orange are due to contaminants called dioxins produced during its chemical synthesis. (For more info on this see 2,4-D and dioxins and also here.)

    How Does 2,4-D Kill Dandelions…?

    First produced in the 1940’s, the herbicide 2,4-D is one of many so-called phenoxy herbicides. These herbicides all are both structural and functional analogs of the plant hormone auxin, more precisely, indole-3-acetic acid (IAA). Such synthetic auxins as 2,4-D are not only structurally similar to IAA, but they are also biologically active as auxins in most plants. Although they both look and act like auxins, plants can not metabolize these phenoxy herbicides as they can with IAA, the natural auxin. This turns out to be the key to why phenoxy herbicides such as 2,4 D are able to kill some plants.

    Auxin-based herbicides are referred to as “selective” herbicides because they kill so-called “broadleaf” plants (a.k.a., dicots) but not grasses, for example. (Hence, that’s why they’re such popular herbicides with both growers of lawns as well as of wheatfields.)

    But how exactly does spraying 2,4-D on susceptible plants kill them?

    This turns out to be very poorly understood, and it’s also the subject of much misinformation. For example, I’ve heard people say that such herbicides kill the plant because ” it grows itself to death”, and I’ve read that 2,4-D “…simply confuses the plant to death”.

    Huh?

    At the present time nobody really knows precisely how the auxin-like herbicides kill susceptible plants. As with most effects of plant hormones, it probably has a lot to do with the plant species in question.

    However, recent findings have provided important clues. And these clues support the idea that plant death may occur as a result of a combination of factors.

    Here’s a summary of the story:

    First off, one of the well-know effects of excess amounts of auxin on dicots is to cause them to overproduce the plant hormone ethylene. For example, in 1969, Mary Hallaway and Daphne J. Osborne first showed that ethylene is a factor in defoliation caused by 2,4-D.

    Because plants can’t break down 2,4-D, it’s action persists. This action includes the excess production of ethylene, which may result in a number of plant responses, including epinasty and senescence.

    Another effect of excess ethylene production in response to 2,4-D is to stimulate the production of yet another plant hormone, abscisic acid (ABA). The effects of ABA on the plant may contribute to eventual plant death. (For an illustration of the complex effects of auxin-based herbicides on plants, see Figure 1 in Ref. 1 below.)

    The most recent review on the subject (see Ref. 3 below) I’ve been able to find doesn’t provide a much clearer picture. Most of the literature on 2,4-D has to do with mechanisms of resistance to this herbicide in plants.

    …and why doesn’t 2,4, D Kill the Grass? (and You?)

    Perhaps the simplest explanation for both questions has to do with sensitivity to the plant hormone auxin.

    In general, grasses are much less sensitive to synthetic auxin herbicides than are dicots. That is, a much higher threshold level of auxin-based herbicide is required to elicit physiological responses in grasses versus the so-called “broadleaf” plants. So, at the doses used to kill dandelions, for example, grasses are largely unaffected. (Higher doses of 2,4-D may kill the grass, too, however.) Grasses may be more resistant to such herbicides because of differences in leaf morphology, translocation of the herbicide inside the plant, and the ability to metabolize (breakdown) synthetic auxins.

    Aside from the toxic contaminant dioxin, 2,4-D has no physiological effects on animals at hormonal levels, that is, at the concentrations that affect plants. (Indeed, there is no reputable evidence that any of the five main plant hormones affects animals.)

    Is Sex Necessary? – For The Common Dandelion, Apparently Not

    Despite efforts to eradicate them using chemical warfare, the dandelions exhibit a remarkable ability to proliferate.

    They do so likely because they produce seeds asexually, that is, without the complications of sexual reproduction, such as pollination.

    This is because most dandelions reproduce by a process called apomixis.

    Unlike other forms of asexual reproduction in plants such as vegetative plant propagation via cuttings, apomixis is asexual reproduction via seeds.

    In the case of most dandelions (i.e., Taraxacum officinale), the embryo in the seed forms without meiosis, thus the offsping are genetically identical to the parent.

    Hence, most, if not all, of the dandelions in your neighborhood may be clones.

    What are the benefits of apomixis?

    Well, despite the lack of the evolutionary benefits of sexual reproduction (lack of diversity), apomixis allows for the “mass production” of seeds, which appears to be an effective strategy for dandelion propagation.

    By rapidly producing cloned offspring, sex is certainly not necessary for the common dandelion.

    Dandelions – Highly Underrated?

    Perhaps to the chagrin of suburban “lawnscapers” who spend so much time and effort and money in eradicating dandelions, did you know that dandelions are actually commercially cultivated in many places in the United States? Vineland, New Jersey, may indeed be the “dandelion capital of the world”. See here and here for why.

    Also, did you know that dandelions can be a significant source of latex for the manufacture of tires (or tyres, if you’re outside the USA or Canada)?

    It’s true! See here and here, for just two links.

    Yes, and because of this, dandelions are plants of interest to biotechnologists in the USA, Germany, and the Netherlands.

    So, despite the fact that millions of pounds of herbicides are used every year to kill them in lawns throughout the USA, dandelions can be used for food and as herbs, to make wine (“mellow yellow”), and even to make tires (or tyres).

    And, There’s More!

    If you’d like more information about these plants that are seemingly ubiquitous this time of year because of their bright yellow flowers, here are some online resources:

    • Dandelions in folklore, in literature, and much more can be found here and here.

    References

    1. Grossmann, K. (2007) “Auxin Herbicide Action: Lifting the Veil Step by Step”, Plant Signaling & Behavior 2:421-423. (PDF)

    2. Grossmann, K. (2010) “Auxin herbicides: current status of mechanism and mode of action.” Pest Management Science, Vol. 66, pp. 113–120, (Abstract)

    3. Song, Y. (2014) “Insight into the mode of action of 2,4-dichlorophenoxyacetic acid (2,4-D) as an herbicide.” Journal of Integrative Plant Biology, Vol. 56, pp. 106-113. (Full Text)

    Up Next: The Selfish Plant – Part 3

    HowPlantsWork © 2008-2017 All Rights Reserved.

    If you know the enemy and know yourself, you need not fear the result of a hundred battles.
    – Sun Tzu, The Art of War

    Who Are You?

    How do plants distinguish “unfriendly” (a.k.a., pathogenic) microbes from “friendly” microbes (with which to form mutually beneficial partnerships, e.g.)?

    How do flowering plants choose their mating partners in order to promote outcrossing?

    There is evidence that some plants can distinguish the roots of related (“kin”) from non-related neighboring plants. How does this “kin recognition” work in plants?

    All of the above situations involve the concept of biological “self” versus “non-self” perception.

    It turns out that how plants distinguish “self” from “non-self” is critically important for plant defense, mutualistic symbioses, successful sexual reproduction in many flowering plants, and maybe even root-root interactions among different plant species.

    Pattern Recognition in Plant Defense and Symbiosis

    One of the most important defense mechanisms against microbial pathogens is a plant’s innate immune system. But what triggers the plant’s immune system to switch the plant from growth and development into a defense mode?

    The ability to distinguish ‘self’ from ‘nonself’ is the most fundamental aspect of any immune system. The evolutionary solution in plants to the problems of perceiving and responding to pathogens involves surveillance of nonself, damaged-self and altered-self as danger signals.” (From Ref. 1 below)

    As mentioned in the previous post, these “danger signals” are distinct, small fragments of cells, either from the plant itself (“self”) or from another biological entity (“non-self”). Plant cells may have an array of different cell-surface receptors, each one activated by a specific cellular fragment.

    In other words, “The first line of defense in plants is the recognition of conserved molecules characteristic of many microbes. These elicitors are also known as microbe- or pathogen-associated molecular patterns (MAMPs or PAMPs). MAMPs are essential structures for the microbes and are for that reason conserved both among pathogens, non-pathogenic and saprophytic microorganisms. MAMPs are recognized by pattern recognition receptors (PRRs), which are localized on the surface of plant cells…” (From Ref. 2 below.)

    Recognition of pathogen-derived molecules by pattern recognition receptors (PRRs) is a common feature of both animal and plant innate immune systems. In plants, PRR signaling is initiated at the cell surface by kinase complexes, resulting in the activation of immune responses that repel microbes.

    “PRRs were first discovered in plants. Since that time many plant PRRs have been predicted by genomic analysis (370 in rice; 47 in Arabidopsis). Unlike animal PRRs, which associated with intracellular kinases via adaptor proteins, plant PRRs are composed of an extracellular domain, transmembrane domain, juxtamembrane domain and intracellular kinase domain as part of a single protein.” (From Wikipedia)

    Interestingly, some of these PRRs also mediate symbiotic signaling (see Ref. 3 below). That is, small, unique molecules from “friendly” microbes, such as Rhizobium bacteria or mycorrhizal fungi, may specifically interact with some plant PRRs, which, in turn, may set in motion “symbiotic” or “mutualistic” responses in the plant.

    Recent findings suggest that, in some instances, the immune response may contribute to the process of symbiotic partner choice in plants (see Ref. 4).

    In short, emerging data suggest that ‘know thyself’, or at least ‘know thy partner’, may be as essential for development of beneficial infections as it is in defence against disease.” (From Ref. 4 below)

    To Be Continued….Self-incompatibilty and Kin Recognition

    References

    1. Sanabria, N. M., J.-C. Huang and I. A. Dubery (2010) “Self/non-self perception in plants in innate immunity and defense.” Self/Nonself, Vol. 1, pp. 40-54. (Full Text)

    2. Newman, M.-A., T. Sundelin, J. T. Nielsen, and G. Erbs (2013) “MAMP (microbe-associated molecular pattern) triggered immunity in plants.” Frontiers in Plant Science, 4:139. doi: 10.3389/fpls.2013.00139 (Full Text)

    3. Antolín-Llovera, M., et al. (2014) “Knowing your friends and foes – plant receptor-like kinases as initiators of symbiosis or defence.” New Phytologist, Vol. 204, pp. 791–802. (Full Text)

    4. Saffo, M. B. (2014) “Mutualistic Symbioses.” In: eLS. John Wiley & Sons, Ltd: Chichester. DOI: 10.1002/9780470015902.a0003281.pub2 (Download PDF for Full Text)

    The Who – Who Are You?

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    The Selfish Plant

    Looking Out For Number One

    In a previous post, way back last December, regarding the notion of plant “pain”, I acknowledged the subject of “damaged-self recognition” in plants, but I didn’t want to elaborate on it at that time.

    Well, it looks like now’s the time….

    “Damaged-self recognition” in plants has to do with how a plant senses that it has been physically injured.

    For example, how does a plant become aware that it’s been physically damaged – by a hailstorm, for instance, or by a herbivore? And can it tell the difference between the two?

    It’s well-known that plants can, and do, respond at the whole-plant (systemic) level when a part of the plant has been physically damaged.

    And recent experimental evidence tends to support the idea that plants can indeed distinguish different kinds of wounding – for example, caterpillar-chewing versus cattle-grazing – and respond differently to each.

    If so, then what are the cellular and whole-plant mechanisms that enable plants to distinguish and to defend themselves against different kinds of wounding?

    Perhaps the chief proponent (evangelist?) of the concept of “damaged-self recognition” in plants is Dr. Martin Heil. (See also an interview with Martin Heil.)

    In his words, here is a partial definition:
    Most elicitors of plant responses to folivory represent, or contain, parts of plant-derived molecules that are degraded, digested or localized outside their original cell compartment. To the plant, these
    elicitors indicate the ‘damaged self’. Such elicitors are released from disrupted cells and are probably perceived by receptors that monitor the extracellular chemistry. Thus, the information on the ‘damaged self’ is transported into the inner compartments of intact and metabolically active cells, which react through metabolic responses such as the synthesis of systemic signals and defence compounds.
    ” (From: Ref. 1 below)

    Briefly put, when a leaf, for example, is grazed by a herbivore (“folivore”), this produces broken pieces of plant cells and plant cell walls. These cellular fragments (“elicitors”) diffuse to surrounding intact cells, which may contain specific receptors for some of these elicitors.

    When these elicitor-receptors are activated, they trigger a chain of cellular processes that lead to the production of chemical “wound signals” that can diffuse throughout the plant, alerting it to the damage and initiating various defensive responses.

    PAMPs, MAMPs, DAMPs and HAMPs

    Multicellular organisms suffer injury and serve as hosts for microorganisms. Therefore, they require mechanisms to detect injury and to distinguish the self from the non-self and the harmless non-self (microbial mutualists and commensals) from the detrimental non-self (pathogens).” (From Ref. 3 below)

    The concept that animals and plants achieve the above by detecting specific molecules produced by, or on the surface of, microbes has been around a long time.

    Immunologists were likely among the first to identify and characterize such molecules. They discovered that cells of the immune system were activated by specific molecules associated with groups of pathogens. They called these elicitors of the immune response pathogen-associated molecular patterns (PAMPs).

    Since then, this concept has expanded and diversified well beyond the field of immunology, even into the realm of plant science.

    So, for example, today we now have MAMPs (microbe-associated molecular patterns) that are recognized by the plant innate immune systems pattern recognition receptors (PRRs).

    In more general terms, we also have damage-associated molecular patterns (DAMPs), also known as “danger-associated molecular patterns” or simply “danger signals”. For example, these may be molecular pieces of plant cells themselves that can act as “elicitors”, as mentioned above. (Please see Ref. 3 below.)

    And, finally, we have “herbivore-associated molecular patterns” (HAMPs) that include specific molecules derived from the regurgitate of feeding caterpillars and also plant-derived protein fragments that are formed specifically during insect feeding. Interestingly, a plant’s defensive responses elicited by HAMPs may differ from those triggered by DAMPs.

    Recent research (see Ref. 4 below) indicates that plants may also use a combination of DAMPs and HAMPs as cues in order to deploy a more fine-tuned response to specific wounding.

    Thus, a plant may possess quite sophisticated mechanisms – as yet to be fully understood – that allows it to not only perceive “damaged-self” but also damage by “non-self”.

    The Selfish Plant

    Delving into the subject of “damaged-self recognition” in plants got me to thinking about other ways plants display an awareness of self. (Dare I say “selfishness”?)

    No, I’m not going to investigate the subject of self-aware plants as it relates to plant “consciousness”. (For that, I’ll refer you to Ref. 5 below.)

    Instead, over the next few posts, lets’s explore the nature of what I’ll call “the selfish plant”.

    Next-Up: Self- and Non-Self Recognition in Plants

    References

    1. Heil, M. (2009) “Damaged-self recognition in plant herbivore defence.” Trends in Plant Science, Vol. 14, pp. 356-363. (Abstract)

    2. Heil, M., et al. (2012) “How Plants Sense Wounds: Damaged-Self Recognition Is Based on Plant-Derived Elicitors and Induces Octadecanoid Signaling.” PLoS ONE 7(2): e30537. doi:10.1371/journal.pone.0030537. (Full Text)

    3. Heil, M. and W. G. Land (2014) “Danger signals – damaged-self recognition across the tree of life.” Frontiers in Plant Science, Vol. 5, article 578. DOI: 10.3389/fpls.2014.00578. (Full Text)

    4. Duran-Flores, D. and M. Heil (2016) “Sources of specificity in plant damaged-self recognition.” Current Opinion in Plant Biology, Vol. 32, pp. 77-87. (Abstract)

    5. Trewavas, A. J. and F. Baluška (2011) “The ubiquity of consciousness.” EMBO Reports, Vol. 12, pp. 1221-1225. (Full Text)

    HowPlantsWork © 2008-2017 All Rights Reserved.

    From A Pumpkin Movie to Jimi Hendrix

    Yep, the plant news from last month was quite diverse.

    Let’s start with two movies – one happens over a time scale of months, and the other happens over a time scale of billionths of seconds.

  • Over the course of five months in 2014 — from a sprouting seed to a fair-ready 1,223 pound pumpkin — competitive pumpkin grower Matt Radach protected and pampered his growing plant, as captured in this time lapse video.

    Growing a 1,223 pound pumpkin from seed to scale in time lapse.

  • Using ultrafast imaging of moving energy in photosynthesis, scientists have determined the speed of crucial processes for the first time.

    First movie of energy transfer in photosynthesis solves decades-old debate.

  • As a growing plant extends its roots into the soil, the new cells that form at their tips assume different roles, from transporting water and nutrients to sensing gravity.
    A new study points to one way by which these newly-formed cells, which all contain the same DNA, take on their special identities.

    Transforming plant cells from generalists to specialists.

  • Sneaky parasitic weeds may steal genes from the plants they are attacking and use those genes against the host plant, according to a team of scientists.

    Parasitic weeds may steal genes from the plants they are attacking.

  • A team of researchers has named a new, rare and endangered succulent found only in Baja California after the rock legend.”

    Jimi Hendrix lends new plant species his name.

    Thanks for all the questions and comments in 2016, and for 2017, Happy Trails!

    HowPlantsWork © 2008-2017 All Rights Reserved.

  • From Where Potatoes Came From to Where Agriculture Is Going

    Last November the plant research news ranged from the past history of one of our most important crop plants to the future of agriculture in the 21st century.

  • November is the month of Thanksgiving in the USA, and one common feature of today’s Thanksgiving feasts was not present at the Pilgrim’s original one – potatoes.

    That’s because potatoes are native to South America and had not yet made their way to North America.
    Where in South America potatoes first became domesticated, however, is still unknown. Recent genetic studies point to the Andean highlands in southern Peru and northwestern Bolivia as the crop’s birthplace, but a lack of direct plant evidence has made it difficult to confirm.”

    Who First Farmed Potatoes? Archaeologists in Andes Find Evidence.

  • The fungus Piriformospora indica colonizes the roots of different plants. This can be orchids, tobacco, barley or even moss. It penetrates into the roots, but does not damage the plants.

    As reported in November of last year, a protein produced by this fungus may be able to suppress the innate immune system of its plant host.

    How a fungus inhibits the immune system of plants.

  • Farmers looking to reduce reliance on pesticides, herbicides and other pest management tools may want to heed the advice of Cornell agricultural scientists: Let nature be nature – to a degree.

    Wicked weeds may be agricultural angels.

  • Millions of years ago, some plants in the mustard family made the switch from simple leaves to complex leaves through two tiny tweaks to a single gene. One tweak to a small enhancer sequence gave the gene a new domain of expression in the leaf. Paradoxically, the other tweak sub-optimised its function in this new domain. But together, these changes gave rise to fit plants with complex leaves.

    A small piece of DNA with a large effect on leaf shape.

  • A decade ago, agricultural scientists at the University of Illinois suggested a bold approach to improve the food supply: tinker with photosynthesis, the chemical reaction powering nearly all life on Earth.
    The idea was greeted skeptically in scientific circles and ignored by funding agencies. But one outfit with deep pockets, the Bill and Melinda Gates Foundation, eventually paid attention, hoping the research might help alleviate global poverty.

    With an Eye on Hunger, Scientists See Promise in Genetic Tinkering of Plants.

    Next Up: The final chapter of the 2016 plant news retrospective.

    HowPlantsWork © 2008-2017 All Rights Reserved.

  • From Flowers That Smell Like Stressed Bees To Corn That Smells Like “Help Me!”

    October 2016 seemed to feature an unusual number of quirky plant news stories.

    For example, we previously saw an orchid that smelled like body odor, presumably to attract mosquitos.

    Now here’s another weird flower smell…

  • A new discovery takes plants’ deception of their pollinators to a whole new level. Researchers reporting in the journal Current Biology on October 6 found that the ornamental plant popularly known as Giant Ceropegia fools certain freeloading flies into pollinating it by mimicking the scent of honeybees under attack.

    This flower smells like a bee under attack.

  • Plants cannot simply relocate to better surroundings when their environmental conditions are no longer suitable. Instead, they have developed sophisticated molecular adaptation mechanisms. Scientists at the Technical University Munich (TUM) in cooperation with the Helmholtz Center Munich and the University of Nottingham have been able to demonstrate that brassinosteroids, which until now have mainly been regarded as growth hormones, increase the resistance of plants against frost.

    Defying frost and the cold with hormones.

  • Of the many elusive grails of agricultural biotechnology, the ability to confer nitrogen fixation into non-leguminous plants such as cereals ranks near the very top.

    Beyond genes: Protein atlas scores nitrogen fixing duet.

  • Here’s – by far – the most retweeted plant research news story of October 2016:

    It’s been a brutal forest fire season in California. But there’s actually a greater threat to California’s trees — the state’s record-setting drought. The lack of water has killed at least 60 million trees in the past four years.
    Scientists are struggling to understand which trees are most vulnerable to drought and how to keep the survivors alive. To that end, they’re sending human climbers and flying drones into the treetops, in a novel biological experiment.

    How Is A 1,600-Year-Old Tree Weathering California’s Drought?.

  • A photoreceptor molecule in plant cells has been found to moonlight as a thermometer after dark – allowing plants to read seasonal temperature changes. Scientists say the discovery could help breed crops that are more resilient to the temperatures expected to result from climate change.

    Plant ‘thermometer’ triggers springtime budding by measuring night-time heat.

  • When corn seedlings are nibbled by caterpillars, they defend themselves by releasing scent compounds that attract parasitic wasps whose larvae consume the caterpillar—but not all corn varieties are equally effective at giving the chemical signal for help.

    Researchers identify genes for “Help Me!” aromas from corn.

    Next Up: The penultimate look at plant news for 2016.

    HowPlantsWork © 2008-2017 All Rights Reserved.

  • From Plant Secrets To Plant Antibiotics

    What were the five most re-tweeted and favorited plant news stories that I shared in September of last year?

    Well, here they are, in order of popularity, lowest to highest.

  • Scientists from the John Innes Centre have pioneered innovative new cell imaging techniques to shed light on cells hidden deep inside the meristem. This new development has made it possible to explore further below the outer surface of plants and has uncovered how a key gene controls stem growth.

    Peeling back the layers: scientists use new techniques to uncover hidden secrets of plant stem development.

  • While we already knew that plant roots were capable of sensing many individual soil characteristics (water, nutrients and oxygen availability), we did not have any understanding of how they integrated these signals in order to respond in an appropriate way. Researchers from CNRS and INRA have just discovered a mechanism that allows a plant to adjust its water status and growth according to different soil flooding conditions.

    How plant roots sense and react to soil flooding.

  • “The mutualistic relationship between tree roots and ectomycorrhizal (ECM) fungi has been shaping forest ecosystems since their inception.

    How fungi help trees tolerate drought.

  • A team that includes a Virginia Tech plant scientist recently used life sciences technology to edit 14 target sites encompassing eight plant genes at a time, without making unintended changes elsewhere in the genome.
    The technology, a genome-editing tool called CRISPR-Cas9, revolutionized the life sciences when it appeared on the market in 2012. It is proving useful in the plant science community as a powerful tool for the improvement of agricultural crops.

    New study of CRISPR-Cas9 technology shows potential to improve crop efficiency.

  • One researcher thinks the drugs of the future might come from the past: botanical treatments long overlooked by Western medicine.

    Could ancient remedies hold the answer to the looming antibiotics crisis?

    So, ethnobotany actually wins over CRISPR-Cas9…

    Next-Up: What were some of the “tastier” plant science news stories in October 2016?

    HowPlantsWork © 2008-2017 All Rights Reserved.

  • From How Sunflowers Track The Sun To Where Strawberries Came From

    The eighth month of the year may be when many people are on holiday (at least in the Northern Hemisphere).

    But plant science news didn’t take a holiday.

    Indeed, there were so many popular reports published last August, it was difficult for me to select only a few.

    Anyway, here are five that you may find particularly “tasty”.

  • Sunflowers not only pivot to face the sun as it moves across the sky during the day, but they also rotate 180 degrees during the night to greet the morning sun. UC Davis and UC Berkeley researchers have now discovered how they do it:

    How sunflowers follow the sun.

  • How rapidly increasing levels of atmospheric CO2, due primarily to human activities, and its climatic consequences will affect the Earth’s terrestrial vegetation is currently one of the most important and active areas plant-related research. Two new findings reported in August 2016 contributed to our understanding of the changes that occurring.

    A University of Otago botany researcher and colleagues have developed a new system to map the world’s “biomes”— large-scale vegetation formations — that will provide an objective method for monitoring how vegetation reacts as climate changes.

    New map of world vegetation reveals substantial changes since 1980s.

    New research from the University of British Columbia suggests evolution is a driving mechanism behind plant migration, and that scientists may be underestimating how quickly species can move.

    Evolution drives how fast plants could migrate with climate change: UBC study.

  • Last August it was reported that a new way of fixing inactive proteins has been discovered in a single-celled algae.

    This repair system may have applications in agriculture and biotechnology because it could potentially be harnessed to enable proteins to become active only in the light.

    Novel “repair system” discovered in algae may yield new tools for biotechnology.

  • Scientists from the University of New Hampshire have unlocked a major genetic mystery of one of the ancestors of cultivated strawberry.

    UNH scientists unravel genetic ancestry of cultivated strawberry.

    Next-Time: Find out what the most re-tweeted plant research news stories were during September 2016.

    HowPlantsWork © 2008-2017 All Rights Reserved.

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