JXB Advance Access originally published online on January 12, 2004
Journal of Experimental Botany, Vol. 55, No. 396, pp. 497-505, February 1, 2004
© 2004 Oxford University Press
Plants and the Environment |
Response to water deficit and high temperature of transgenic peas (Pisum sativum L.) containing a seed-specific 
-amylase inhibitor and the subsequent effects on pea weevil (Bruchus pisorum L.) survival
Received 29 January 2003; Accepted 13 October 2003
1 Department of Environmental Biology, Curtin University of Technology PO Box U1987, Perth, WA 6845, Australia
2 Western Australian Department of Agriculture, Locked Bag No.4, Bentley, WA 6983, Australia
3 CSIRO Plant Industry, Private Bag No. 5, Wembley, WA 6913, Australia
4 CSIRO Plant Industry, GPO Box 1600, Canberra, ACT 2601, Australia
* To whom correspondence should be addressed. E-mail: M.Majer{at}curtin.edu.au
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Abstract |
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The effects of water deficit and high temperature on the production of
-amylase inhibitor 1 (-AI-1) were studied in transgenic peas (Pisum sativum L.) that were developed to control the seed-feeding pea weevil (Bruchus pisorum L., Coleoptera: Bruchidae). Transgenic and non-transgenic plants were subjected to water-deficit and high-temperature treatments under controlled conditions in the glasshouse and growth cabinet, beginning 1 week after the first pods were formed. In the water-deficit treatments, the peas were either adequately watered (control) or water was withheld after first pod formation. The high-temperature experiments were performed in two growth cabinets, one maintained at 27/22 °C (control) and one at 32/27 °C day/night temperatures, with the vapour pressure deficit maintained at 1.3 kPa. The plants exposure to high temperatures and water deficit produced 27% and 79% fewer seeds, respectively, than the controls. In the transgenic peas the level of -AI-1 as a percentage of total protein was not influenced by water stress, but was reduced on average by 36.3% (the range in two experiments was 11–50%) in the high-temperature treatment. Transgenic and non-transgenic pods of plants grown at 27/22 °C and 32/27 °C were inoculated with pea weevil eggs to evaluate whether the reduction in level of -AI-1 in the transgenic pea seeds affected pea weevil development and survival. At the higher temperatures, 39% of adult pea weevil emerged, compared to 1.2% in the transgenic peas grown at the lower temperatures, indicating that high temperature reduced the protective capacity of the transgenic peas. Key words: Alpha-amylase inhibitor, Bruchus pisorum, high-temperature stress, Pisum sativum, transgenic peas, water deficit.
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Introduction |
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TopAbstractIntroductionMaterials and methodsResultsDiscussionReferences |
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Environmental stresses, such as extreme levels of light, temperature, water deficit, or nutrient deficiency, reduce the agricultural production and quality of many crops (Lawlor, 1979; Boyer, 1982; Xiong et al., 1999). In Australia, the major environmental factors influencing field pea are drought and high temperatures during the spring flowering period (Ali et al., 1994). These adverse environmental conditions are responsible for a considerable loss of production in the field, losses that could be the result of environmental effects on a range of genetic and molecular mechanisms (for reviews, see Zhu et al., 1997; Ingram and Bartels, 1996; Bohnert et al., 1995; Bray, 1993; Nguyen and Joshi, 1992). Significant production losses in field pea can also result from damage by the seed-feeding beetle, Bruchus pisorum L. (pea weevil) (Smith, 1990b).
A gene for the -amylase inhibitor 1 (-AI-1) has been transferred from the common bean (Phaseolus vulgaris L.) to the field pea (Pisum sativum L.) to limit damage by the pea weevil (Shade et al., 1994; Schroeder et al., 1995; Morton et al., 2000). The efficient cultivation and commercial success of transgenic plants depends on the continued expression of the introduced genes during periods of stress (Neumann et al., 1997; Sachs et al., 1998; Traore et al., 2000).
Severe environmental factors have been reported to influence the success of genetically modified crops under field conditions (Benedict et al., 1992, 1996; De Rocher et al., 1998; Sachs et al., 1998), resulting in variable performance (Kaiser, 1996; Jenkins et al., 1997; Sachs et al., 1998). The efficacy of presquare Bt cotton plants is reported to be significantly affected by the temperature regime and the efficacy against the main pest, Helicoverpa armigera, declines during the season (Olsen et al., 2001). Studies on transgenic maize (Zea mays L.) resistant to European corn borer (Ostrinia nibilalis L.) have shown that water stress affects the level of Bt proteins (Traore et al., 2000). In transgenic petunia (Petunia hydrida), the maize A1 gene encoding a dihydroflavonol reductase was inactivated in about 60% of the plants after a period of high light intensity and temperatures up to 36 °C (Meyer et al., 1992). In transgenic tomato (Lycopersicon esculentum L.) fruits exposed to prolonged incubation times at 27 °C and 38 °C, the introduced gene encoding for polygalacturonase and pectin methylesterase was inactivated at the higher temperature (Kagan-Zur et al., 1995; Lurie et al., 1996). Finally, Neumann et al. (1997) reported that in transgenic tobacco (Nicotiana tabacum L.) plants and seedlings maintained at 37 °C, a reduction or complete loss of luciferase-encoded activities occurred in 40% of the transgenic tobacco lines.
The present study focused on whether the level of the -amylase inhibitor (-AI-1) varied when transgenic peas were grown under water and heat stress and, if the inhibitor level was affected, whether this had any influence on the ability of the transgenic plants to control the development of the pea weevil.
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Materials and methods |
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Plant material
The garden pea (Pisum sativum L.) cv. Greenfeast and a transgenic Greenfeast line (F10) expressing
-amylase inhibitor (-AI-1) from common bean (Phaseolus vulgaris L.) in its seeds were used in these studies (Shade et al., 1994; Schroeder et al., 1995).
Growth of plant material
Four experiments were conducted. In each, pots (diameter 250 mm and 235 mm deep) with saucers underneath were filled with a base cover of about 5 cm crushed pine bark and with coarse river sand to give a total weight of 11 kg. Four pea seeds were inoculated with Group E Bradyrhizobium inoculum and sown in each pot. The four plants in each pot were treated with Phostrogen® fertilizer every 2 weeks and automatically watered daily until the start of the experiments. During the period from sowing until flowering, the plants for all four experiments were grown in a glasshouse under natural light with maximum and minimum temperatures of 27–31 °C and 11–14 °C, respectively, and maximum and minimum relative humidities (RH) of 96–97% and 47–60%, respectively. Pots with different genotypes and treatments were randomized in the glasshouse (i.e. moved weekly to a different position). Pods were tagged when they were visible (i.e. 5–6 mm long), hereafter defined as ‘pod set’, which was 3–4 d after flowering, and the tagging date recorded. In one experiment the flowers were tagged when fully open.
In the first experiment, the transgenic and non-transgenic peas were grown in the glasshouse and kept adequately watered in order to compare seed development. In the second experiment, the plants were kept in the glasshouse and water was withheld from half the pots, beginning on the first day after pod set, to determine the effect of water stress on seed development and -amylase inhibitor level. The remaining plants were watered daily. In the third experiment, all plants were transferred from the glasshouse to controlled-environment growth cabinets when flowering commenced. For 2 weeks, the plants were grown in two cabinets at 27/22 °C day/night temperatures. To determine the influence of high temperature on the level of -amylase inhibitor, the temperature in one cabinet was then increased to 32/27 °C day/night, while light and vapour pressure deficit (VPD) were unchanged. In the fourth experiment transgenic and non-transgenic peas were grown at the same high and low temperatures as in Experiment 3 and eggs of the pea weevil transferred to the pods at the onset of seed filling, about 8–10 d after flowering, to determine the influence of temperature on pea weevil survival.
Experiment 1: pod and seed growth of transgenic and non-transgenic peas
Six pots were sown with transgenic seed (4 plants pot–1), six with non-transgenic seed (4 plants pot–1) and the plants grown in the glasshouse with average maximum and minimum temperatures of 28 °C and 12 °C, respectively, and average maximum and minimum RHs of 97% and 60% RH, respectively, over the entire growing period. Each pod was tagged at pod set and the dates of pod set recorded. Five or more pods of the same age were randomly sampled every 3–4 d over 5 weeks from the 24 plants of the two lines. At each sampling, the pods and seeds were separated, oven dried overnight and the weighs recorded.
Experiment 2: effect of a water deficit
Six pots (4 plants pot–1) each of transgenic and non-transgenic peas were sown and kept in the glasshouse with average maximum and minimum temperatures of 27 °C and 11 °C, respectively, and average maximum and minimum RHs of 97% and 60% RH, respectively, until maturity. At pod set, pods were tagged every 2–3 d over a 12 d period and the date recorded. One week after first pod set, half of the transgenic and half of the non-transgenic plants were randomly designated as controls and the other half to the water-deficit treatment. In both treatments the soil was covered with white plastic beads to reduce soil evaporation, watered until there was slight through-drainage, and 24 h later the pots plus saucers were weighed. This weight was considered to be the pot capacity (Jones et al., 1980). Thereafter, pots were weighed daily to determine water use. Control pots were returned to pot capacity daily, while in the water stress treatment the pots were never re-watered. The extractable soil water was the difference in the amount of water between pot capacity (100%) and that at which no further water loss was detectable (0%) and was calculated in relative terms on an individual pot basis (Turner et al., 1985). Pods were harvested at maturity (63–67 d after first pod set) into separate bags, weighed and grouped according to the date of pod set (a) prior to the imposition of water stress (Pre-T); (b) set within 3 d of the stress treatment (IP-T); and (c) later than 4 d after stress imposition (Post-T). Seeds and pod walls were weighed separately, the number of seeds per pod counted, and seed yield per plant was calculated. Seeds were stored dry at 20 °C for the subsequent analysis of total protein and -amylase inhibitor content.
Experiment 3: effect of high temperature
Eight pots (4 plants pot–1) each of transgenic and non-transgenic peas were grown in a glasshouse with average maximum and minimum temperatures of 27 °C and 11 °C, respectively, and average maximum and minimum RHs of 97% and 60%, respectively, until flowering. Thereafter, four pots each of transgenic and non-transgenic peas, assigned randomly, were placed in each of two cabinets. For 2 weeks, both cabinets were kept at 27/22 °C day/night, with a 12 h photoperiod, and a continuous vapour pressure deficit (VPD) of 1.3 kPa. The plants were automatically watered to excess three times daily to keep the soil near pot capacity. After 2 weeks, the temperature in one cabinet was adjusted to 32/27 °C day/night temperatures and the VPD was maintained at 1.3 kPa, while the second cabinet was maintained at 27/22 °C (day/night) with a VPD of 1.3 kPa. Pods were tagged at pod set and harvested at maturity and analysed as in Experiment 2.
Experiment 4: pea weevil survival in transgenic peas at high temperature
As in Experiment 3, eight pots (4 plants pot–1) each of transgenic and non-transgenic peas were grown in a glasshouse with average maximum and minimum temperatures of 31 °C and 14 °C, respectively, and average maximum and minimum RHs of 96% and 47%, respectively, until flowering. At flowering, they were transferred to two controlled environment cabinets as described in Experiment 3 and the flowers tagged daily. Viable pea weevil eggs, ‘black spotted’ eggs in which the dark brown head capsule of the larva was visible (Smith, 1990a), were obtained from colonies maintained at the Western Australian Department of Agriculture, South Perth. These eggs were transferred to the exterior pod wall 8–10 d after flowering, using a wet No. 0 brush (Hardie, 1993). Mature pods were harvested and the seed analysed for total protein and -amylase inhibitor content. The seeds were observed under a dissecting microscope and examined for the presence of pea weevil larvae. Pea weevil larvae have four instars, which all develop within the seed, feeding on cotyledon contents and ultimately forming an exit hole, covered by the transparent membrane of the testa (termed a ‘window’). After reaching the 4th instar, the larva pupates and, later, transforms into an adult that is ready to emerge from the seed (Skaife, 1918; Brindley, 1933; Smith, 1990a, b; Morton et al., 2000). The stage of larval development and presence of pupae or adults was recorded.
Determination of -amylase inhibitor-1 level
The -amylase inhibitor level was assayed in transgenic seeds from Experiments 2, 3 and 4 by western blot analysis. The seeds were ground to the consistency of fine flour and the soluble protein from 20 mg of meal from each sample was extracted by vortex using a 1.5 ml Eppendorf tube with 1 ml protein extraction buffer (0.5 M NaCl, 0.1 M TES, 1mM EDTA). The samples were centrifuged at 14 000 rpm for 300 s and the supernatant containing soluble protein transferred to a fresh tube. Total protein concentration was determined according to Bradford (1976), and -AI levels were determined from the western blots as described by Schroeder et al. (1995) and Morton et al. (2000).
Statistical analyses
Two- and three-way analyses of variance were performed using the Super ANOVA statistical program (Abacus Concepts, 1989) and Zar (1999). The -AI values were square root transformed before analysis in order to normalize the variance.
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Results |
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Pod and seed growth of transgenic and non-transgenic peas
In both the transgenic and non-transgenic peas grown under unstressed conditions, pod wall dry weight increased rapidly to reach a maximum about 20 d after pod set and subsequently decreased (Fig. 1). After an initial lag phase of 6 d, individual seed weight increased sigmoidally to a maximum at about 35 d after pod set (Fig. 1). No significant difference in weight gain of the pod walls or seeds was observed between transgenic and non-transgenic peas.
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Effect of a water deficit
After the cessation of watering, the relative extractable water content of the soil decreased rapidly to 20% of that at pot capacity over the first 4–5 d and decreased more slowly to reach zero in all pots by 15 d (Fig. 2). Regular watering maintained the control plants near pot capacity (Fig. 2). There was no difference in the relative extractable water content between the pots containing the transgenic and non-transgenic plants at any time in both the control and water-deficit treatments. The measurements of leaf relative water content (Sousa-Majer, 2002) showed that the leaves of both the transgenic and non-transgenic peas lost water content for the first 10 d after the water-deficit treatment was imposed, but were unchanged in the control plants.
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Water deficits significantly reduced the number of seeds per pod (P=0.0001), weight per seed (P
0.0001) and pod wall weight (P 0.0001) in transgenic and non-transgenic peas (Table 1). The transgenic seeds were also significantly (P 0.05) smaller than the non-transgenic seeds under the water-deficit conditions.
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While the level of protein as a percentage of dry weight increased significantly from 27.8% in watered seeds to 36.3% in water-stressed seeds, western blot analysis revealed that the water stress did not have any significant effect on the level of the
-AI-1 expressed per unit of protein present in the transgenic pea seeds (Fig. 3a).
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Effect of high temperature and response to pea weevil attack
The high-temperature treatment significantly reduced the number of seeds per pod (P
0.0001) and the pod wall weight (P=0.025) in both transgenic and non-transgenic plants, but did not have a significant effect on weight per seed (Table 2). However, the weight per seed of the transgenic plants was lower than that of non-transgenic seeds at both temperatures (Table 2). There were no significant differences in the transgenic plants for total protein per seed (Fig. 4a), but a reduction in the levels of -AI-1 expressed on a protein basis (Fig. 4b) as a result of the high-temperature treatment that was consistent among the three groups of pods representing the different pod-setting periods (Fig. 4a, b).
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There was a 40.6% (range 33–48%) reduction in the level of
-AI-1 in transgenic pea seeds that were subjected to 32/27 °C compared with those at 27/22 °C in Experiment 3 (P=0.0013) (Figs 3b, 4b). Western blot analyses of the transgenic pea seeds in Experiment 4 indicated that the high-temperature treatment decreased the level of the -AI-1 by 33.2% (range 11–50%), which is in the same range as the reduction observed in Experiment 3 (Fig. 3b, c). In the non-transgenic peas grown at 27/22 °C and 32/27 °C, 92% and 94%, respectively, of the pea weevils emerged as adults (Fig. 5). In the transgenic peas, only 1.2% of the adult pea weevils emerged as adults at 27/22 °C, whereas 39% emerged as adults at 32/27 °C (Fig. 5). Table 3 shows the mean number of larvae or pupae alive at each instar in cohorts of inoculated seeds from transgenic and non-transgenic plants grown under the two temperature regimes. Analysis of the non-transgenic peas grown at either temperature revealed very few larvae, most having already emerged as adults. By contrast, transgenic peas grown at 27/22 °C had, on average, 2% of pea seeds still containing live larvae at the 1st to 2nd instar, 5% containing live larvae at the 2nd to 3rd instar, 6% containing live larvae at the 3rd to 4th instar, and 0.4% containing live larvae at the 4th instar or pupae. Thus total survival was about 14% (Table 3). When grown at 32/27 °C, the corresponding figures for transgenic peas were 1.2%, 9%, 15.4%, and 19%, respectively, giving a total survival of about 82%.
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Discussion |
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The results of this study clearly indicate that water stress reduced seed size, increased the protein concentration in the seed, but did not alter the proportion of
-amylase inhibitor (-AI-1) in the seed of the transgenic Greenfeast peas on a protein basis (but increased the level of -AI-1 on a dry weight basis), as summarized in Table 4. By contrast, high temperatures during seed set and seed filling had no effect on seed size or protein level, but reduced the level of -AI-1 in the transgenic peas (Table 4), allowing pea weevil larvae to survive to later instars in the seed and a greater number of pea weevil to emerge as adults, thereby making the transgenic peas much more susceptible to pea weevil attack. This suggests that the release of weevil-resistant transgenic peas in regions where high temperatures occur during seed filling should proceed with caution.
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Apart from the insertion of the inhibitor gene, the transgenic peas were similar to the non-transgenic peas. A comparison of seed and pod growth in transgenic and non-transgenic peas, under adequate water and glasshouse temperature conditions, showed that there was no difference in pod or seed dry weight during development. These results agree with Schroeder et al. (1995), who reported that the homozygous transgenic T4 and T5 pea seeds were phenotypically indistinguishable from their non-transgenic counterparts, when no pea weevils were present and the plants were not grown under environmental stress. However, in the plants grown in the controlled environmental cabinets, the final seed weights of the transgenic peas were about 10% smaller than the non-transgenic peas at both 27/22 °C and 32/27 °C, and also in the water stress experiment, raising the possibility that under some environmental conditions the transgenic seeds may be less ‘fit’ than the non-transgenic peas.
Consistent with earlier data for peas (Baigorri et al., 1999; Martín et al., 1994) and other pulses (Doss et al., 1974; Sionit and Kramer, 1977; Korte et al., 1983a, b; Meckel et al., 1984; Vieira et al., 1992; De Souza et al., 1997), the water deficit during flowering and pod development reduced seed size, seed number per pod and, consequently, reduced yield per plant by 21% in both the transgenic and non-transgenic peas (Table 1). The decrease in seed size was associated with an increase in seed protein (% dry mass) from 28% to 36%. A similar increase in the level of protein in the seed of chickpea under water stress has been reported by Behboudian et al. (2001). The water deficit, however, did not affect the level of -AI-1 when expressed per unit of protein present (Fig. 4a) and clearly increased the level of -AI-1 on a dry weight basis by 30%.
By contrast with the effect of the water deficit, exposure to high temperatures (32/27 °C) during flowering and pod development had no effect on seed size or total protein in both the transgenic and non-transgenic peas, but significantly reduced the number of seeds per pod. Consequently, seed yield per plant was reduced by 27%. More importantly, in the transgenic peas, exposure to temperatures of 32/27 °C reduced the level of -AI-1 in the seeds (Table 4; Fig. 3b, c). An explanation for the reduced level of -AI-1 at high temperatures is not known, but the reduction in -amylase level may have arisen from effects on transcription of the DNA or the translation of messenger RNA (Neumann et al., 1997; Gallie and Pitto, 1996; Meyer and Saedler, 1996).
High-temperature stress is often confounded by water stress because of higher water use at such temperatures (McWilliam, 1980). In the present study care was taken to ensure that the high-temperature treatment was not confounded by water deficits by watering the plants three times a day and maintaining the day/night vapour pressure deficit at 1.3 kPa at both temperatures in both experiments. The maintenance of weight per seed at high temperatures suggests that water deficits did not occur. The lower seed numbers per pod is consistent with results of high temperature on cowpea (Vigna unguiculata L.) (Hall, 1992) and common bean (Gross and Kigel, 1994). The latter showed that high temperatures during flowering reduced seed set, because pollen damage resulted in poor fertilization and embryo abortion.
The reduction in -amylase inhibitor by one-third to one-half had a marked effect on the survival of larvae and emergence of pea weevils from the transgenic peas. Morton et al. (2000) reported that larvae feeding on -AI-1 seeds at room temperature died at an early stage and this is consistent with Sousa-Majer (2002), who reported that in transgenic peas larvae died at the 1st to early 3rd instar stage at 24±2 °C. In non-transgenic peas, the pea weevil larvae normally burrow into the seed and develop through to the 4th instar larval stage, pupate and emerge (Brindley, 1933), resulting in reduced seed weight because the larvae eat the seed contents. Larvae that reach the 4th instar stage are responsible for the greatest part of the damage (Brindley and Hinman, 1937; Smith, 1990b). Thus, for the -amylase inhibitor to be effective it is important to prevent larvae reaching the late-3rd instar stage. In the present study, high temperatures allowed 19% of larvae to reach the 4th instar or pupal stage in the transgenic peas (Table 3). This was in addition to the 39% pea weevils that had already emerged as adults (Fig. 5), giving a total of 58% survival of larvae to a stage at which they induce major damage to seed of transgenic peas. Larvae at late-3rd and 4th instar are also likely to continue to develop in the mature seed, giving a total pea weevil survival of 
70%. By contrast at 27/22 °C, only 1.2% adults emerged, and only 0.4% of larvae in the 4th instar and pupal stage, 6% of larvae in 3rd to 4th instar were still alive in the transgenic peas, indicating that seed containing -AI-1 inhibitor protein is very effective in suppressing insect survival at lower temperatures and more effective than reported by Schroeder et al. (1995). While the development and survival of larvae was not evaluated in the water-deficit treatment, the fact that the level of -AI-1 inhibitor was similar on a protein basis and increased on a dry weight basis suggests that larval development and survival would possibly be further inhibited by water deficit from the 1.2% adult emergence observed in the transgenic peas in the well-watered conditions at 27/22 °C.
These results have implications for the release of the transgenic insect-resistant peas. They strongly suggest that environmental conditions, particularly exposure to high temperatures, can influence the efficacy of the transgenic peas in controlling the insect. Temperatures in the range of those used in this study are not uncommon in some areas where peas are grown. For example, in Western Australia, it is possible to experience maximum temperatures greater than 27 °C for 4–22 d during flowering and pod-filling (Sousa-Majer, 2002). However, in the field studies reported by Sousa-Majer (2002), while day temperatures above 27 °C occurred for several days, there was no significant increase in pea weevil survival under field conditions. This raises several questions for future investigation. While the temperatures used in the experiments were consistent with the maximum temperature observed in the field, the peas were exposed to a constant high temperature of 32 °C for 12 h d–1, whereas maximum temperatures in the field only occur for a short period around midday. Thus, experiments are required using diurnal temperatures mimicking the field situation to determine whether the reduction in -AI-1 and increase in insect survival are similar to those observed in this study. Nevertheless, caution is definitely required when considering the release of transgenic peas into warmer regions (Sousa-Majer, 2002)
In conclusion, this study has shown that water deficits and high temperatures during flowering and pod development had differing effects in both transgenic and non-transgenic peas. Water stress imposed during seed filling affected seed size, seed number and yield and increased the level of -AI-1 in seeds on a dry weight basis. High temperatures imposed during seed filling had no effect on seed size, but the number of seeds per pod and seed yield per plant were reduced and the level of -AI-1 was reduced on average by 36.3% in transgenic peas, allowing 39% of adults pea weevil to emerge compared to 1.2% in the transgenic peas grown at 27/22 °C. Thus, for the control of pea weevil, the transgenic peas should be grown only under cool conditions; release into hotter environments needs to be undertaken with caution. These results will help to design better guidelines for risk-assessment of transgenic crops in general.
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Acknowledgements |
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Dr Rob Rippingale, Associate Professor Rick Roush, and Dr Stephen Clement are thanked for critically reading and commenting on this manuscript. Also Drs Tanveer Khan and Bob French are thanked for advise on field pea planting and flowering period. Meg Flavelle and Simone Dudley are thanked for setting up the growth cabinets and Andy Moore for helping with the western blot analysis. The Western Australian Department of Agriculture and CSIRO Plant Industry kindly provided facilities in order to carry out this work. This research was supported by the Grains Research Committee (GRC) of Western Australia and a Curtin University Postgraduate Award.
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References |
|---|
|
TopAbstractIntroductionMaterials and methodsResultsDiscussionReferences |
|---|
Abacus Concepts. 1989. SuperANOVA. Berkeley, CA: Abacus Concepts, Inc.
Ali SM, Sharma B, Ambrose MJ. 1994. Current status and future strategy in breeding pea to improve resistance to biotic and abiotic stresses. Euphytica 73, 115–126.
Baigorri H, Antolin MC, Sanchez-Diaz M. 1999. Reproductive response of two morphologically different pea cultivars to drought. European Journal of Agronomy 12, 119–128.[CrossRef]
Behboudian MH, Ma Q, Turner NC, Palta JA. 2001. Discrimination against 13CO2 in leaves, pods walls, and seeds of water-stressed chickpea. Photosynthetica 38, 155–157.[CrossRef]
Benedict JH, Altman DW, Umbeck PF, Ring DR. 1992. Behavior, growth, survival, and plant injury for Heliothis virescens (F.) (Lepidoptera: Noctuidae) on transgenic Bt cottons. Journal of Economic Entomology 85, 589–593.
Benedict JH, Sachs ES, Altman DW, Deaton WR, Kohel RJ, Ring DR, Berberich SA. 1996. Field performance of cottons expressing transgenic CryIA insecticidal proteins for resistance to Heliothis virescens and Helicoverpa zea (Lepidoptera: Noctuidae). Journal of Economic Entomology 89, 230–238.
Bohnert HJ, Nelson DE, Jensen RG. 1995. Adaptations to environmental stresses. The Plant Cell 7, 1099–1111.[CrossRef][ISI][Medline]
Boyer JS. 1982. Plant productivity and environment. Science 218, 443–448.
Bradford MM. 1976. A rapid and sensitive method for the quantification of microgram quantities of proteins utilizing the principle of protein–dye binding. Analytical Biochemistry 72, 248–254.[CrossRef][ISI][Medline]
Bray EA. 1993. Molecular responses to water deficit. Plant Physiology 103, 1035–1040[ISI][Medline]
Brindley TA. 1933. Some notes on the biology of the pea weevil Bruchus pisorum L. (Coleoptera, Bruchidae) at Moscow, Idaho. Journal of Economic Entomology 26, 1058–1062.
Brindley TA, Hinman FG. 1937. Effect of growth of pea weevil on weight and germination of seed peas. Journal of Economic Entomology 30, 664–670.
De Rocher EJ, Vargo-Gogola TC, Diehn SH, Green PJ. 1998. Direct evidence for rapid degradation of Bacillus thuringiensis toxin mRNA as a cause of poor expression in plants. Plant Physiology 117, 1445–1461.
De Souza PI, Egli DE, Bruening WP. 1997. Water stress during seed filling and leaf senescence in soybean. Agronomy Journal 89, 807–812.
Doss BD, Pearson RW, Rogers HT. 1974. Effect of soil water stress at various growth stages on soybean yield. Agronomy Journal 66, 297–299.
Gallie DR, Pitto L. 1996. Translational control during recovery from heat shock in the absence of heat shock proteins. Biochemical and Biophysical Research Communications 227, 462–467.[CrossRef][ISI][Medline]
Gross Y, Kigel J. 1994. Differential sensitivity to high temperature of stages in the reproductive development in common bean (Phaseolus vulgaris L.). Field Crops Research 36, 201–212.[CrossRef]
Hall AE. 1992. Breeding for heat tolerance. Plant Breeding Reviews 10, 129–167.
Hardie DC. 1993. Resistance to the pea weevil in Pisum species. PhD thesis, The University of Adelaide, Australia, 140pp.
Ingram J, Bartels D. 1996. The molecular basis of dehydration tolerance in plants. Annual Review of Plant Physiology and Plant Molecular Biology 47, 377–403.[CrossRef][ISI][Medline]
Jenkins JN, McCarty JC, Buechler JRE, Kiser J, Williams C, Wofford T. 1997. Resistance of cotton with 
-endotoxin genes from Bacillus thuringiensis var. kurstaki on selected lepidopteran insects. Agronomy Journal 89, 768–780.
Jones MM, Osmond CB, Turner NC. 1980. Accumulation of solutes in leaves of sorghum and sunflower in response to water deficits. Australian Journal of Plant Physiology 7, 193–203.
Kagan-Zur V, Tieman DM, Marlow SJ, Handa AK. 1995. Differential regulation of polygalacturonase and pectin methylesterase gene expression during and after heat stress in ripening tomato (Lycopersicon esculentum Mill.) fruits. Plant Molecular Biology 29, 1101–1110.[CrossRef][ISI][Medline]
Kaiser J. 1996. Pests overwhelm cotton crop. Science 273, 423.[CrossRef][ISI]
Korte LL, Williams JH, Specht JE, Sorensen RC. 1983a. Irrigation of soybean genotypes during reproductive ontogeny. I. Agronomic responses. Crop Science 23, 521–527.
Korte LL, Specht JE, Williams JH, Sorensen RC. 1983b. Irrigation of soybean genotypes during reproductive ontogeny. II. Yield component responses. Crop Science 23, 528–533.
Lawlor DW. 1979. Effects of water and heat stress on carbon metabolism of plants with C3 and C4 photosynthesis. In: Mussel H and Staples RC, eds. Stress physiology in crops plants. New York: John Wiley, 304–326.
Lurie S, Handros A, Fallik E, Shapira R. 1996. Reversible inhibition of tomato fruit gene expression at high temperature. Plant Physiology 110, 1207–1214.[Abstract]
Martín I, Tenorio JL, Ayerbe L. 1994. Yield, growth, and water use of conventional and semi-leafless peas in semi-arid environments. Crop Science 34, 1576–1583.
McWilliam JR. 1980. Summary and synthesis-adaptation to high-temperature stress. In: Turner NC, Kramer PJ, eds. Adaptation of plants to water and high-temperature stress. New York: John Wiley, 444–446.
Meckel L, Egli DB, Philips RE, Radcliffe D, Leggett JE. 1984. Effect of moisture stress on seed growth in soybean. Agronomy Journal 76, 647–650.
Meyer P, Linn F, Heidmann I, Meyer ZAH, Neiedenhof I, Sedler H. 1992. Endogenous and environmental factors influence 35S promotor methylation of a maize A1 gene construct in transgenic plant petunia and its color phenotype. Molecular and General Genetics 231, 345–352.
Meyer P, Saedler H. 1996. Homology-dependent gene silencing in plants. Annual Review of Plant Physiology and Plant Molecular Biology 47, 23–48.[CrossRef][ISI]
Morton RL, Schroeder HE, Bateman KS, Chrispeels MJ, Armstrong E, Higgins TJV. 2000. Bean alpha amylase inhibitor 1 in transgenic peas (Pisum sativum) provides complete protection from pea weevil (Bruchus pisorum) under field conditions. Proceedings of the National Academy of Sciences, USA 97, 3820–3825.
Neumann K, Droge-Laser W, Kohne S, Broer I. 1997. Heat treatment results in a loss of transgene-encoded activities in several tobacco lines. Plant Physiology 115, 939–947.[Abstract]
Nguyen HT, Joshi PC. 1992. Molecular strategies for the genetic dissection of water and high-temperature stress adaptation in cereal crops. Proceedings of an international symposium on the adaptation of food crops to temperature and water stress, 13–18 August 1992, Taiwan, 1–19.
Olsen K, Daly J, Finnegan J, Holt H, Mahon R. 2001. The effect of two environmental factors, temperature and insect damage, on the efficacy of presquare Bt cotton plants. In: Gupta VVSR, ed. Proccedings of 4th Pacific rim conference on the biotechnology of Bacillus thuringiensis and its environmental impact, 11–15 November 2001, Australian National University, Australia, 37.
Sachs ES, Benedict JH, Stelly DM, Taylor JF, Altaman DW, Berberich SA, Davis SK. 1998. Expression and segregation of genes encoding CryIA insecticidal proteins in cotton. Crop Science 38, 1–11.
Schroeder HE, Gollasch S, Moore A, Tabe LM, Craig S, Hardie DC, Chrispeels MJ, Spencer D, Higgins TJV. 1995. Bean -amylase inhibitor confers resistance to the pea weevil (Bruchus pisorum) in transgenic peas (Pisum sativum L.). Plant Physiology 107, 1233–1239.[Abstract]
Shade RE, Schroeder HE, Pueyo JJ, Tabe LM, Murdock LL, Higgins TJV, Chrispeels MJ. 1994. Transgenic pea seeds expressing the -amylase inhibitor of the common bean are resistant to bruchid beetles. Biotechnology 12, 793–796.[CrossRef]
Sionit N, Kramer PJ. 1977. Effect of water stress during different stages of growth of soybeans. Agronomy Journal 69, 274–278.
Skaife SH. 1918. Pea and bean weevils. Bulletin of the Department of Agriculture, Union of South Africa 12, 1–32.
Smith AM. 1990a. Development and mortality of pea weevil, Bruchus pisorum (L.), in field peas in Victoria. In: Smith AM, ed. Proceedings of the national pea weevil workshop, 9–10 May 1990. Melbourne, Australia: Department of Agriculture and Rural Affairs, 25–33.
Smith AM. 1990b. Pea weevil (Bruchus pisorum L.) and crop-loss implications for management. In: Fujii K, Gatehouse AMR, Johnson CD, Mitchell R, Yoshida T, eds. Bruchids and legumes: economics, ecology and coevolution. The Netherlands: Kluwer Academic Publishers, 105–114.
Sousa-Majer MJ. 2002. Evaluation of the efficacy of transgenic peas against the pea weevil (Bruchus pisorum). PhD thesis, Curtin University of Technology, Perth, Australia.
Traore SB, Carlson RE, Pilcher CD, Rice ME. 2000. Bt and non-Bt maize growth and development as affected by temperature and drought stress. Agronomy Journal 92, 1027–1035.
Turner NC, Schulze, E-D, Gollan T. 1985. The responses of stomata and leaf gas exchange to vapour pressure deficits and soil water content. II. In the mesophytic herbaceous species Helianthus annuus. Oecologia 65, 348–355.[CrossRef]
Vieira RD, Tekrony DM, Egli DB. 1992. Effect of drought and defoliation stress in the field on soybean seed germination and vigor. Crop Science 32, 471–475
Xiong L, Ishitani M, Zhu J-K. 1999. Interaction of osmotic stress, temperature, and abscisic acid in the regulation of gene expression in Arabidopsis. Plant Physiology 119, 205–212.
Zar JH. 1999. Biostatistical analysis. London: Prentice Hall International, Inc.
Zhu JK, Hasegawa PM, Bressan RA. 1997. Molecular aspects of osmotic stress in plants. Critical Reviews in Plant Sciences 16, 253–277.
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