01 12 / 2013

28 8 / 2013

Volunteer GM wheat, mischief or carelessness?

Volunteer GM wheat, mischief or carelessness?

27 8 / 2013

Medieval iconography of watermelons in Mediterranean Europe
The watermelon, Citrullus lanatus (Cucurbitaceae), is an important fruit vegetable in the warmer regions of the world. Watermelons were illustrated in Mediterranean Antiquity, but not as frequently as some other cucurbits. Little is known concerning the watermelons of Mediterranean Europe during medieval times. With the objective of obtaining an improved understanding of watermelon history and diversity in this region, medieval drawings purportedly of watermelons were collected, examined and compared for originality, detail and accuracy.

Medieval iconography of watermelons in Mediterranean Europe

The watermelon, Citrullus lanatus (Cucurbitaceae), is an important fruit vegetable in the warmer regions of the world. Watermelons were illustrated in Mediterranean Antiquity, but not as frequently as some other cucurbits. Little is known concerning the watermelons of Mediterranean Europe during medieval times. With the objective of obtaining an improved understanding of watermelon history and diversity in this region, medieval drawings purportedly of watermelons were collected, examined and compared for originality, detail and accuracy.

26 8 / 2013

Characterization of rhizosphere fungi that mediate resistance in tomato against bacterial wilt disease
Plant immunization for resistance against a wide variety of phytopathogens is an effective strategy for plant disease management. Seventy-nine plant growth-promoting fungi (PGPFs) were isolated from rhizosphere soil of India. Among them, nine revealed saprophytic ability, root colonization, phosphate solubilization, IAA production, and plant growth promotion. Seed priming with four PGPFs exhibited early seedling emergence and enhanced vigour of a tomato cultivar susceptible to the bacterial wilt pathogen compared to untreated controls. Under greenhouse conditions, TriH_JSB27 and PenC_JSB41 treatments remarkably enhanced the vegetative and reproductive growth parameters. Maximum NPK uptake was noticed in TriH_JSB27-treated plants. A significant disease reduction of 57.3% against Ralstonia solanacearum was observed in tomato plants pretreated with TriH_JSB27. Furthermore, induction of defence-related enzymes and genes was observed in plants pretreated with PGPFs or inoculated with pathogen. The maximum phenylalanine ammonia lyase (PAL) activity (111U) was observed at 24h in seedlings treated with TriH_JSB27 and this activity was slightly reduced (99U) after pathogen inoculation. Activities of peroxidase (POX, 54U) and β-1,3-glucanase (GLU, 15U) were significantly higher in control plants inoculated with pathogen after 24h and remained constant at all time points. A similar trend in gene induction for PAL was evident in PGPFs-treated tomato seedlings with or without pathogen inoculation, whereas POX and GLU were upregulated in control plus pathogen-inoculated tomato seedlings. These results determine that the susceptible tomato cultivar is triggered after perception of potent PGPFs to synthesize PAL, POX, and GLU, which activate defence resistance against bacterial wilt disease, thereby contributing to plant health improvement.

Characterization of rhizosphere fungi that mediate resistance in tomato against bacterial wilt disease

Plant immunization for resistance against a wide variety of phytopathogens is an effective strategy for plant disease management. Seventy-nine plant growth-promoting fungi (PGPFs) were isolated from rhizosphere soil of India. Among them, nine revealed saprophytic ability, root colonization, phosphate solubilization, IAA production, and plant growth promotion. Seed priming with four PGPFs exhibited early seedling emergence and enhanced vigour of a tomato cultivar susceptible to the bacterial wilt pathogen compared to untreated controls. Under greenhouse conditions, TriH_JSB27 and PenC_JSB41 treatments remarkably enhanced the vegetative and reproductive growth parameters. Maximum NPK uptake was noticed in TriH_JSB27-treated plants. A significant disease reduction of 57.3% against Ralstonia solanacearum was observed in tomato plants pretreated with TriH_JSB27. Furthermore, induction of defence-related enzymes and genes was observed in plants pretreated with PGPFs or inoculated with pathogen. The maximum phenylalanine ammonia lyase (PAL) activity (111U) was observed at 24h in seedlings treated with TriH_JSB27 and this activity was slightly reduced (99U) after pathogen inoculation. Activities of peroxidase (POX, 54U) and β-1,3-glucanase (GLU, 15U) were significantly higher in control plants inoculated with pathogen after 24h and remained constant at all time points. A similar trend in gene induction for PAL was evident in PGPFs-treated tomato seedlings with or without pathogen inoculation, whereas POX and GLU were upregulated in control plus pathogen-inoculated tomato seedlings. These results determine that the susceptible tomato cultivar is triggered after perception of potent PGPFs to synthesize PAL, POX, and GLU, which activate defence resistance against bacterial wilt disease, thereby contributing to plant health improvement.

25 8 / 2013

Science’s Special Issue on Smarter Pest Control includes news and reviews on the plant immune system, pesticide’s effect on young brains, and preventing suicides by locking up pesticides.

12 8 / 2013

11 8 / 2013

GMO debate: inconclusive


In his Foreword to my book Haldane’s Daedalus Revisited, Nobel laureate Joshua Lederberg (1995) correctly emphasized the difficulty of making accurate scientific predictions. Nevertheless, I agree with M. S. Swaminathan (2012) that the current concerns of biosafety will soon give way to an appreciation of the potential benefits of the new genetics including the GMO technology. I have reviewed the subject of GMOs in agriculture in my book: “Emerging Consequences of Biotechnology” (2009).

GMO debate: inconclusive

In his Foreword to my book Haldane’s Daedalus Revisited, Nobel laureate Joshua Lederberg (1995) correctly emphasized the difficulty of making accurate scientific predictions. Nevertheless, I agree with M. S. Swaminathan (2012) that the current concerns of biosafety will soon give way to an appreciation of the potential benefits of the new genetics including the GMO technology. I have reviewed the subject of GMOs in agriculture in my book: “Emerging Consequences of Biotechnology” (2009).

10 8 / 2013

Caffeine suppresses homologous recombination through interference with RAD51-mediated joint molecule formation
Caffeine is a widely used inhibitor of the protein kinases that play a central role in the DNA damage response. We used chemical inhibitors and genetically deficient mouse embryonic stem cell lines to study the role of DNA damage response in stable integration of the transfected DNA and found that caffeine rapidly, efficiently and reversibly inhibited homologous integration of the transfected DNA as measured by several homologous recombination-mediated gene-targeting assays. Biochemical and structural biology experiments revealed that caffeine interfered with a pivotal step in homologous recombination, homologous joint molecule formation, through increasing interactions of the RAD51 nucleoprotein filament with non-homologous DNA. Our results suggest that recombination pathways dependent on extensive homology search are caffeine-sensitive and stress the importance of considering direct checkpoint-independent mechanisms in the interpretation of the effects of caffeine on DNA repair.

Caffeine suppresses homologous recombination through interference with RAD51-mediated joint molecule formation

Caffeine is a widely used inhibitor of the protein kinases that play a central role in the DNA damage response. We used chemical inhibitors and genetically deficient mouse embryonic stem cell lines to study the role of DNA damage response in stable integration of the transfected DNA and found that caffeine rapidly, efficiently and reversibly inhibited homologous integration of the transfected DNA as measured by several homologous recombination-mediated gene-targeting assays. Biochemical and structural biology experiments revealed that caffeine interfered with a pivotal step in homologous recombination, homologous joint molecule formation, through increasing interactions of the RAD51 nucleoprotein filament with non-homologous DNA. Our results suggest that recombination pathways dependent on extensive homology search are caffeine-sensitive and stress the importance of considering direct checkpoint-independent mechanisms in the interpretation of the effects of caffeine on DNA repair.

09 8 / 2013

The value and use of social media as communication tool in the plant sciences
Social media now complements many parts of our lives. Facebook, Twitter, YouTube and many other social networking sites allow users to share and interact with online content and to connect with like-minded people. Its strengths – rapid dissemination and amplification of content and the ability to lead informal conversations – make it a powerful tool to use in a professional context. This commentary explains the overall concept of social media and offers suggestions on usage and possible types of scientific content. It advises researchers on the potential benefits and how to take a strategic approach towards building a social media presence. It also presents examples of effective social media use within the plant science community. Common reasons for scientists to not engage with social media include the fear of appearing unprofessional, posting something wrong or being misunderstood, or a lack of confidence in their computer skills. With the rapid changes in academic publishing, dissemination and science communication, as well as the rise of ‘altmetrics’ to track online engagement with scientific content, digital literacy will become an essential skill in a scientist’s tool kit.

The value and use of social media as communication tool in the plant sciences

Social media now complements many parts of our lives. Facebook, Twitter, YouTube and many other social networking sites allow users to share and interact with online content and to connect with like-minded people. Its strengths – rapid dissemination and amplification of content and the ability to lead informal conversations – make it a powerful tool to use in a professional context. This commentary explains the overall concept of social media and offers suggestions on usage and possible types of scientific content. It advises researchers on the potential benefits and how to take a strategic approach towards building a social media presence. It also presents examples of effective social media use within the plant science community. Common reasons for scientists to not engage with social media include the fear of appearing unprofessional, posting something wrong or being misunderstood, or a lack of confidence in their computer skills. With the rapid changes in academic publishing, dissemination and science communication, as well as the rise of ‘altmetrics’ to track online engagement with scientific content, digital literacy will become an essential skill in a scientist’s tool kit.

08 8 / 2013

Plant biology in reduced gravity on the Moon and Mars
While there have been numerous studies on the effects of microgravity on plant biology since the beginning of the Space Age, our knowledge of the effects of reduced gravity (less than the Earth nominal 1 g) on plant physiology and development is very limited. Since international space agencies have cited manned exploration of Moon/Mars as long-term goals, it is important to understand plant biology at the lunar (0.17 g) and Martian levels of gravity (0.38 g), as plants are likely to be part of bioregenerative life-support systems on these missions. First, the methods to obtain microgravity and reduced gravity such as drop towers, parabolic flights, sounding rockets and orbiting spacecraft are reviewed. Studies on gravitaxis and gravitropism in algae have suggested that the threshold level of gravity sensing is around 0.3 g or less. Recent experiments on the International Space Station (ISS) showed attenuation of phototropism in higher plants occurs at levels ranging from 0.l g to 0.3 g. Taken together, these studies suggest that the reduced gravity level on Mars of 0.38 g may be enough so that the gravity level per se would not be a major problem for plant development. Studies that have directly considered the impact of reduced gravity and microgravity on bioregenerative life-support systems have identified important biophysical changes in the reduced gravity environments that impact the design of these systems. The author suggests that the current ISS laboratory facilities with on-board centrifuges should be used as a test bed in which to explore the effects of reduced gravity on plant biology, including those factors that are directly related to developing life-support systems necessary for Moon and Mars exploration.

Plant biology in reduced gravity on the Moon and Mars


While there have been numerous studies on the effects of microgravity on plant biology since the beginning of the Space Age, our knowledge of the effects of reduced gravity (less than the Earth nominal 1 g) on plant physiology and development is very limited. Since international space agencies have cited manned exploration of Moon/Mars as long-term goals, it is important to understand plant biology at the lunar (0.17 g) and Martian levels of gravity (0.38 g), as plants are likely to be part of bioregenerative life-support systems on these missions. First, the methods to obtain microgravity and reduced gravity such as drop towers, parabolic flights, sounding rockets and orbiting spacecraft are reviewed. Studies on gravitaxis and gravitropism in algae have suggested that the threshold level of gravity sensing is around 0.3 g or less. Recent experiments on the International Space Station (ISS) showed attenuation of phototropism in higher plants occurs at levels ranging from 0.l g to 0.3 g. Taken together, these studies suggest that the reduced gravity level on Mars of 0.38 g may be enough so that the gravity level per se would not be a major problem for plant development. Studies that have directly considered the impact of reduced gravity and microgravity on bioregenerative life-support systems have identified important biophysical changes in the reduced gravity environments that impact the design of these systems. The author suggests that the current ISS laboratory facilities with on-board centrifuges should be used as a test bed in which to explore the effects of reduced gravity on plant biology, including those factors that are directly related to developing life-support systems necessary for Moon and Mars exploration.