NEWS FROM
PHYSIOLOGIA PLANTARUM
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Published monthly on behalf of SPPS by Wiley-Blackwell.
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Function of mitochondria in desiccation tolerance
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When seeds mature they loose most protoplasmic water and eventually holds no free water in the cells. This calls for a number of protective mechanisms to protect the structure and function of macromolecules and membranes, including the mitochondria whose function is imperative for the seed's ability to germinate after rehydration. In order to study this, Song-Quan Song from The Chinese Academy of Sciences in Beijing, China investigated mitochondrial function and structure of pea (Pisum sativum) seeds during germination after various sequential imbibition, dehydration and re-imbibition treatments. It turned out that while the outer mitochondrial membrane kept its integrity in all treatments, integrity of the inner mitochondrial membrane and cytochrome respiratory function was more labile after prolonged imbibition (more than 12 hours) and this correlated with decreased desiccation tolerance. Imbibition in the presence of CaCl2, however, increased desiccation tolerance, suggesting the requirement for Ca2+ in mitochondrial membrane structure and function.
Read full article here: Wang et al (January 2012) Physiologia Plantarum 144: 20
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NEWS IN BRIEF
FROM OTHER JOURNALS
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How to hijack genes
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Source: Deng et al (5 January 2012) Science doi:10.1126/science.1215670 & Mak et al (5 January 2012) Science doi:10.1126/science.1216211
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Failed water management caused decline of the Khmer Empire
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Source: Day et al (3 January 2012) PNAS doi:10.1073/pnas.1111282109
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Scandinavian research institute:
Faculty of Landscape Planning, Horticulture and Agricultural Sciences, SLU, Sweden
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SLU is divided into 4 faculties located at 4 main campuses. From www.slu.se
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SLU (Swedish University of Agricultural Sciences or Sveriges Lantbruksuniversitet) is a university seated under the Ministry for Rural Affairs and, accordingly, is highly focused on research in biological resources and production. With a total staff of 2900, 700 graduate students and 4000 undergraduate students, the university deals with almost all topics related to agriculture, forestry and food industry to environmental questions, veterinary medicine and biotechnology. SLU is divided into four faculties located at four main campuses spread around the country: In this issue of the SPPS Newsletter we will present the Faculty of Landscape Planning, Horticulture and Agricultural Sciences, which is located at the campus in Alnarp in the southernmost part of Sweden.
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Landscape, horticulture and agriculture takes the lime light at the SLU faculty in Alnarp. Photo collage by Gorm Palmgren
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The faculty is further divided into 8 departments, one of which is Plant Breeding and Biotechnology headed by Tomas Bryngelsson. Two main approaches are taken, namely molecular markers to facilitate breeding and modification of biosynthetic pathways to improve crop quality. To the first end, the department is working with a minor oil crop, niger (Guizotia abyssinica), that is mainly grown in northeastern Africa. It has been recognized as a neglected and underutilized species, since little scientific interest in the crop has led to a lack of tools for improving it by means of modern breeding techniques. In cooperation with international research groups, however, Mulato Geleta and colleagues have now established an extensive library of ESTs, chloroplast genomic data and nuclear microsatellite markers that can prove useful in further efforts to improve the crop.
Taking the biotechnological approach, Margareta Welander and Li-Hua Zhu might have overcome some of the food safety issues with genetically engineered crops. Instead of transforming the crop per se they decided to manipulate the rootstock onto which an apple bearing scion was grafted. Rootstocks that induce dwarfing in the scion are generally preferred, but since they can be hard to root, the researchers transformed it with the root inducing rolB gene from Agrobacterium tumefasciens. The results showed, that while the the transgenic rootstocks were both easy to root and induced the desired dwarfing phenotype of the scion, the fruit quality remained high. It was further shown, that neither the rolB transgene or its mRNA was translocated from the rootstock to the scion, so the harvested apples remained unmodified and 'natural'. This approach might lead to higher consumer acceptance and easier approval.
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Pheromones are used to disrupt mating of pests on vineyards in Northern Italy. From J Chem Ecol (2010) 36: 80
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Another department, Plant Protection Biology headed by Ylva Hillbur, takes several different approaches to the problems of keeping crops free from pests. One of them deals with the use of sex pheromones to control the behavior of insects. In a review from 2010, Peter Witzgall describes how pheromones are already being used on more than 1 million hectares of farmland to lure insects into traps. Since pheromones are generally safe chemicals, they do not harm the environment and due to their extreme efficiency they can even be used at low pest densities. In cooperation with Italian colleagues in 2010 he used eletroantennographic measurements and wind tunnel bioassays to demonstrate which blend of odors from grapevine (Vitis vinifera) was most attractive to the female grapevine moth (Lobesia botrana).
Erik Andreasson from the department is studying mitogen-activated protein kinase (MAPK) signal transduction cascades involved in eg defence responses. A large program for understanding plant-pathogen interactions in potato is currently undertaken, financed by the Swedish foundation for Strategic research. In this program mainly a proteomic approach is taken. Together with Erland Liljeroth induced resistance against late blight caused by Phytophtora infestans has been investigated in field studies with promising results. Agents that inducing resistance that has been used is beta.amino butyric acid (BABA) and Potassium phosphate (K2HPO3). The group has recently found a Paranoid potato clone in a breeding program that has defense system activated even without challenged of a pathogen.
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Late blight caused by Phytophtora infestans is a severe pathogen in potatoes. From www.omafra.gov.on.ca
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In cooperation with Malin Hultberg from the Department of Horticulture they have also studied biological control of late blight on potatoes. This destructive disease is caused by the oomycete Phytophtera infestans and has proven very hard to manage without frequent applications of fungicides. The researchers found, however, that the bacteria Pseudomonas koreensis produced a biosurfactant that inhibited fungal zoospores and caused a significant disease reduction. Biosurfactants are produced by the bacteria in order to allow them to grow on water-immiscible substrates, and this effect apparently interfered with zoospore germination.
Other research at the Department of Horticulture, which is headed by Håkan Asp, embrace pre- and post-harvest quality of crops. A number of different polyacetylenes are present in carrots and they are known for both bitter off-tastes and pleasant flavours. Lars Kjellenberg and colleagues have studied the amounts of various polyacetylenes in fresh and stored carrots under different circumstances. HPLC analysis published in 2010 revealed that the relative and absolute amounts of three polyacetylenes - falcarinol, falcarindiol, and falcarindiol-3- acetate - varied according to the time of harvest, but during storage the amounts of polyacetylenes leveled off and became more similar. Based on these studies, the authors propose that carrots harvested by the end of the season will be expected to have better taste and more health-promoting effects.
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Joint research from Departments of Agrosystems and Landscape Architecture deals with the perception of pesticide use. From www.visualphotos.com
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Participating in the polyacetylene studies was also Eva Johansson from the Department of Agrosystems. This department is headed by Erik Steen Jensen and carries out research on sustainable and multifunctional cropping systems for both conventional and organic farming systems. In a recent study from 2011, researchers from the department investigated how the timing of nitrogen application affected wheat grain protein accumulation. The results indicated that a desired high gluten strength was best achieved by early nitrogen application.
Another line of research by Nur Ahmed also involves Mats Lieberg from the Department of Landscape Architecture (headed by Anders Larsson) and concerns how pesticide use are perceived by the farmers themselves and their neighbors. The study used a questionnaire send out to 1200 farmers and non-farmers living in semi-rural areas between the suburbs and the countryside. The study found, as could have been expected, that neighbors had a more negative perception of pesticide use, but more surprisingly the majority of neighbors actually used pesticide for their own gardens. However, they did not think of themselves as pesticide users and, as the authors suggest, this could play a role for regulations of pesticide use.
Three additional departments - Landscape Management (headed by Anders Kristoffersson), Rural Buildings and Animal Husbandry (headed by Eva von Wachenfelt) and Work Science, Business Economics and Environmental Psychology (headed by Peter Lundqvist) - are not included in this overview but you can read more about them and the Faculty of Landscape Planning, Horticulture and Agricultural Sciences at SLU in Alnarp on the official homepage.
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