ERA Banner

Allen Good

RSS Feed
Share

My basic interest lies in understanding how plants adapt to a variety of different environmental stresses, such as disease, flooding, drought or nutrient deficiency. My approach involves using a combination of classical genetic tools, and the modern tools of molecular biology and genomics. This strategy is based on the premise that while the reductionist approach that modern gene cloning tools provide has been very valuable, a detailed understanding of how plants adapts to a stress will require an understanding of how the genotype interacts with specific genes and gene combinations. One of my rationales for combining a genetic approach with molecular biology is to give students a broad background in both classical and molecular genetics. I believe that this approach will provide students with the kind of training that will be required to solve the more complex problems that plant biologists are now starting to address.

Allen Good

Department of Biological Sciences

Room: G 425A, Biological Sciences
Phone: (780) 492-1905
Fax: (780) 492-9234
Email: allen.good@ualberta.ca
Curriculum Vitae

  • Professor, Biological Sciences

  • GENEius Award (2007) Seed Growers Association of Canada 2007
  • AVAC/ASTech Innovation in Agriculture Award 2002
  • Weed Science, Outstanding Scientific Paper (Annual award) 2001
  • International Society of Plant Molecular Biology, Scientific Organizing Committee 2000
  • International Society of Plant Molecular Biology - Chair (Plant Stress) 2000
  • Canadian Society of Plant Physiology - Science Policy Director 1998-1999
  • Canadian Genetics Society - Western Canadian Director 1998-2000

http://hdl.handle.net/10402/era.17193

Subject areas and related deposits

  • Agricultural productivity

    • Engineering nitrogen use efficiency with alanine aminotransferase.

      Nitrogen (N) is the most important factor limiting crop productivity worldwide. The ability of plants to acquire N from applied fertilizers is one of the critical steps limiting the efficient use of nitrogen. To improve N use efficiency, genetically modified plants that overexpress alanine aminotransferase (AlaAT) were engineered by introducing a barley AlaAT cDNA driven by a canola root specific promoter (btg26). Compared with wild-type canola, transgenic plants had increased biomass and seed yield both in the laboratory and field under low N conditions, whereas no differences were observed under high N.The transgenics also had increased nitrate influx. These changes resulted in a 40% decrease in the amount of applied nitrogen fertilizer required under field conditions to achieve yields equivalent to wild-type plants

      Download
  • Alga selenastrum-minutum

    • Long term anaerobic metabolism in root tissue: Metabolic products of pyruvate metabolism

      The onset of anaerobiosis in barley root tissue (Hordeum vulgare L. cv Himalaya) results in the following metabolic responses. There are rapid increases in the levels of pyruvate, lactate, and ethanol. Malate and succinate concentrations increase over the first 12 h, after which they return to the levels found in oxygenated root tissue. Alanine concentration increases over the first 12 h, and this is matched by a corresponding decrease in aspartate. The initial stoichiometric decline in aspartate and increase in alanine suggests that the amino group of aspartate is conserved by transaminating pyruvate to alanine. Aspartate catabolism also probably provides the initial source of carbon for reduction to succinate under anoxic conditions. Under long-term anaerobiosis (>24 h), there is no further accumulation of any of the fermentative end products other than ethanol, which also represents the major metabolic end product during long-term anaerobiosis. Although a number of the enzymes involved in fermentative respiration have been found to be induced under anaerobic conditions, neither aspartate aminotransferase nor malate dehydrogenase is induced in barley root tissue. The observations suggest that the long-term adaptations to hypoxic conditions may be quite different than the more well-characterized short-term adaptations.

      Download
  • Brassica

    • The effects of drought stress on the water relations in Brassica

      The physiological responses of different species of Brassica to induced drought stress were studied by analysing the relationships between relative water content, leaf water potential and leaf osmotic potential during the onset of drought stress. These data indicate that while there was a decrease in leaf osmotic potential with the onset of drought stress, this did not result from a net increase in solutes. Therefore, these genotypes of Brassica do not appear able to osmoregulate under these drought conditions.

      Download
  • Carthamus tinctorius/genetics

  • Flea beetles

  • Gene families

    • The APETALA-2-Like Transcription Factor OsAP2-39 Controls Key Interactions between Abscisic Acid and Gibberellin in Rice

      The interaction between phytohormones is an important mechanism which controls growth and developmental processes in plants. Deciphering these interactions is a crucial step in helping to develop crops with enhanced yield and resistance to environmental stresses. Controlling the expression level of OsAP2-39 which includes an APETALA 2 (AP2) domain leads to phenotypic changes in rice. Overexpression of OsAP2-39 leads to a reduction in yield by decreasing the biomass and the number of seeds in the transgenic rice lines. Global transcriptome analysis of the OsAP2-39 overexpression transgenic rice revealed the upregulation of a key Abscisic Acid (ABA) biosynthetic gene OsNCED-I which codes for 9-cis-epoxycarotenoid dioxygenase and leads to an increase in the endogenous ABA level. In addition to OsNCED-1, the gene expression analysis revealed the upregulation of a gene that codes for the Elongation of Upper most Internode (EUI) protein, an enzyme that catalyzes 16a, 17-epoxidation of non-13-hydroxylated GAs, which has been shown to deactivate gibberellins (GAs) in rice. The exogenous application of GA restores the wild-type phenotype in the transgenic line and ABA application induces the expression of EUI and suppresses the expression of OsAP2-39 in the wild-type line. These observations clarify the antagonistic relationship between ABA and GA and illustrate a mechanism that leads to homeostasis of these hormones. In vivo and in vitro analysis showed that the expression of both OsNCED-1 and EUI are directly controlled by OsAP2-39. Together, these results reveal a novel mechanism for the control of the ABA/GA balance in rice which is regulated by OsAP2- 39 that in turn regulates plant growth and seed production.

      Download
  • Glyoxylate aminotransferase

    • Purification and characterization of an anaerobically induced alanine aminotransferase from barley roots

      Alanine aminotransferase (AlaAT, EC 2.6.1.2) is an enzyme that is induced under anaerobic conditions in cereal roots. In barley (Hordeum vulgare L.) roots, there are a number of isoforms of AlaAT. We have identified the anaerobically induced isoform and have purified it to homogeneity. The isolation procedure involved a two-step ammonium sulfate precipitation, gel filtration, ion-exchange chromatography, and chromatofocusing. The enzyme was purified approximately 350-fold to a specific activity of 2231 units/milligram protein. The apparent molecular masses of the native and sodium dodecyl sulfate-denatured AlaAT proteins are 97 and 50 kilodaltons, respectively, indicating that the native enzyme is probably a homodimer. AlaAT has a number of interesting characteristics when compared with other plant aminotransferases. AlaAT does not require the presence of pyridoxyl-5-phosphate to retain its activity, and it appears to be very specific in the reactions that it will catalyze.

      Download
  • Maize root-tips

    • Enhanced low oxygen survival in Arabidopsis through increased metabolic flux in the fermentative pathway

      We manipulated the enzyme activity levels of the alcohol fermentation pathway, pyruvate decarboxylase (PDC), and alcohol dehydrogenase (ADH) in Arabidopsis using sense and antisense overexpression of the corresponding genes (PDC1, PDC2, and ADH1). Transgenic plants were analyzed for levels of fermentation and evaluated for changes in hypoxic survival. Overexpression of either Arabidopsis PDC1 or PDC2 resulted in improved plant survival. In contrast, overexpression of Arabidopsis ADH1 had no effect on flooding survival. These results support the role of PDC as the control step in ethanol fermentation. Although ADH1 null mutants had decreased hypoxic survival, attempts to reduce the level of PDC activity enough to see an effect on plant survival met with limited success. The combination of flooding survival data and metabolite analysis allows identification of critical metabolic flux points. This information can be used to design transgenic strategies to improve hypoxic tolerance in plants.

      Download
  • Nitrogen-use efficiency

    • Fertilizing Nature: A Tragedy of Excess in the Commons

      Globally, we are applying excessive nitrogen (N) fertilizers to our agricultural crops, which ultimately causes nitrogen pollution to our ecosphere. The atmosphere is polluted by N2O and NOx gases that directly and indirectly increase atmospheric warming and climate change. Nitrogen is also leached from agricultural lands as the water-soluble form NO3-, which increases nutrient overload in rivers, lakes, and oceans, causing ‘‘dead zones’’, reducing property values and the diversity of aquatic life, and damaging our drinking water and aquatic-associated industries such as fishing and tourism. Why do some countries show reductions in fertilizer use while others show increasing use? What N fertilizer application reductions could occur, without compromising crop yields? And what are the economic and environmental benefits of using directed nutrient management strategies?

      Download
  • Outcrossing

    • Pollen-mediated gene flow from transgenic safflower ( Carthamus tinctorius L.) intended for plant molecular farming to conventional safflower

      Field experiments were conducted in Chile and western Canada to measure short-distance (0 to 100 m) outcrossing from transgenic safflower (Carthamus tinctorius L.) intended for plant molecular farming to nontransgenic commodity safflower of the same variety. The transgenic safflower used as the pollen source was transformed with a construct for seed-specific expression of a high-value protein and constitutive expression of a gene conferring resistance to the broad-spectrum herbicide glufosinate. Progeny of non-transgenic plants grown in plots adjacent to the transgenic pollen source were screened for glufosinate resistance to measure outcrossing frequency. Outcrossing frequency differed among locations: values closest to the transgenic pollen source (0 to 3 m) ranged from 0.48 to 1.67% and rapidly declined to between 0.0024 to 0.03% at distances of 50 to 100 m. At each location, outcrossing frequency was spatially heterogeneous, indicating insects or wind moved pollen asymmetrically. A power analysis assuming a binomial distribution and a range of alpha values (type 1 error) was conducted to estimate an upper and lower confidence interval for the probable transgenic seed frequency in each sample. This facilitated interpretation when large numbers of seeds were screened from the outcrossing experiments and no transgenic seeds were found. This study should aid regulators and the plant molecular farming industry in developing confinement strategies to mitigate pollen mediated gene flow from transgenic to non-transgenic safflower.

      Download
  • Rape Brassica-Napus

    • Introgression potential between safflower (Carthamus tinctorius) and wild relatives of the genus Carthamus

      Background: Safflower, Carthamus tinctorius, is a thistle that is grown commercially for the production of oil and birdseed and recently, as a host for the production of transgenic pharmaceutical proteins. C. tinctorius can cross with a number of its wild relatives, creating the possibility of gene flow from safflower to weedy species. In this study we looked at the introgression potential between different members of the genus Carthamus, measured the fitness of the parents versus the F1 hybrids, followed the segregation of a specific transgene in the progeny and tried to identify traits important for adaptation to different environments. Results: Safflower hybridized and produced viable offspring with members of the section Carthamus and species with chromosome numbers of n = 10 and n = 22, but not with n = 32. The T-DNA construct of a transgenic C. tinctorius line was passed on to the F1 progeny in a Mendelian fashion, except in one specific cross, where it was deleted at a frequency of approximately 21%. Analyzing fitness and key morphological traits like colored seeds, shattering seed heads and the presence of a pappus, we found no evidence of hybrid vigour or increased weediness in the F1 hybrids of commercial safflower and its wild relatives. Conclusion: Our results suggest that hybridization between commercial safflower and its wild relatives, while feasible in most cases we studied, does not generate progeny with higher propensity for weediness.

      Download
  • Rice (wild)

    • Annual variation in wild rice (Zizania palustris L.) in Saskatchewan; growth and potential yield

      Mature wild rice plants collected from 20 sites across northern Saskatchewan over the period 1984-1987 were measured for various morphological traits. Considerable regional variation was noted for factors such as stem length, degree of tillering and seed production with plants in the west being generally more robust. Differences also occurred between years. Much of this variation appeared to be related to environmental conditions with high water levels being particularly detrimental to the plants. Seeds collected at each site during the 1986 harvest were sown into growth tanks. Plant development under uniform growing conditions was compared to individuals collected from corresponding natural sites. Although intersite variability was considerably reduced indicating a high degree of environmental plasticity in the population, some regional variation in tillering and seed production was still detectable in the artificial populations and plants from eastern sites still tended to flower earlier. Such inherent genetic variability should be considered when seed is introduced into new sites as the industry expands in northern Saskatchewan.

      Download
  • Triticum-Aestivum L

    • Al-Induced, 51-Kilodalton, Membrane-Bound Proteins Are Associated with Resistance to Al in a Segregating Population of Wheat

      Incorporation of S-35 into protein is reduced by exposure to Al in wheat (Triticum aestivum), but the effects are genotype-specific. Exposure to 10 to 75 mu M Al had little effect on S-35 incorporation into total protein, nuclear and mitochondrial protein, microsomal protein, and cytosolic protein in the Al-resistant cultivar PT741. In contrast, 10 mu M Al reduced incorporation by 21 to 38% in the Al-sensitive cultivar Katepwa, with effects becoming more pronounced (31-62%) as concentrations of Al increased. We previously reported that a pair of 51-kD membrane-hound proteins accumulated in root tips of PT741 under conditions of Al stress. We now report that the 51-kD band is labeled with S-35 after 24 h of exposure to 75 mu M Al. The specific induction of the 51-kD band in PT741 suggested a potential role of one or both of these proteins in mediating resistance to Al. Therefore, we analyzed their expression in single plants from an F-2, population arising from a cross between the PT741 and Katepwa cultivars. Accumulation of 1,3-beta-glucans (callose) in root tips after 24 h of exposure to 100 mu M Al indicated that this population segregated for Al resistance in about a 3:1 ratio. A close correlation between resistance to Al (low callose content of root tips) and accumulation of the 51-kD band was observed, indicating that at least one of these proteins cosegregates with the Al-resistance phenotype. As a first step in identifying a possible function, we have demonstrated that the 51-kD band is most clearly associated with the tonoplast. Whereas Al has been reported to stimulate the activity of the tonoplast HC-ATPase and H+-PPase, antibodies raised against these proteins did not cross-react with the 51-kD band. Efforts are now under way to purify this protein from tonoplast-enriched fractions.

      Download
    • Induction of Vacuolar ATPase and Mitochondrial ATP Synthase by Aluminum in an Aluminum-Resistant Cultivar of Wheat

      Two 51-kD aluminum (Al)-induced proteins (RMP51, root membrane proteins of 51 kD) were recently discovered in an aluminum-resistant cultivar of wheat (Triticum aestivum) cv PT741 (Basu et al., 1994a). These proteins segregate with the aluminum resistance phenotype in a segregating population arising from a cross between Al-resistant cv PT741 and Al-sensitive cv Katepwa (Taylor et al., 1997). The proteins have been purified by continuous elution electrophoresis and analyzed by peptide microsequencing. Sequence analysis of the purified peptides revealed that they are homologous to the B subunit of the vacuolar H(+)-ATPase (V-ATPase) and the alpha- and beta -subunits of the mitochondrial ATP synthase (F(1)F(0)-ATPase). To confirm that these ATPases are induced by Al, ATPase activity and transcript levels were analyzed under Al stress. Both V-ATPase and F(1)F(0)-ATPase activities were induced by Al and responded in a dose-dependent manner to 0 to 150 muM Al. In contrast, plasma membrane H(+)-ATPase (P-ATPase) activity decreased to 0.5x control levels, even when plants were exposed to 25 muM Al. Northern analysis showed that the transcript encoding the B subunit of V-ATPase increased by 2.2x in a dose-dependent manner, whereas levels of the transcript encoding the alpha -subunit of F(1)F(0)-ATPase remained constant. The effect of Al on ATPase activity in other cultivars was also examined. The Al-resistant cultivar, cv PT741, was the only cultivar to show induction of V- and F(1)F(0)-ATPases. These results suggest that the V-ATPase in cv PT741 is responding specifically to Al stress with the ATP required for its activity supplied by ATP synthase to maintain energy balance within the cell.

      Download