Progress 02/01/10 to 01/31/14
Outputs
Target Audience: Target audience is fellow scientists, breeders and stress physiologist and graduate students working in these areas Changes/Problems:
Nothing Reported
What opportunities for training and professional development has the project provided? Graduate student Gerardine Mukeshimana successfully completed a doctoral program and Amy Lasley successfully completed a master’s program in Plant Breeding, Genetics and Biotechnology in 2012. Two doctoral students Valerio Hoyos-Villegas and Jesse Traub continue to work in the project. Three undergraduate students, Lucas Consanza, Mary Marshall and Cindy Amstutz assisted in the program, conducting bean hybridization, DNA extraction, running SCAR and RAPD markers, and disease screening. The group hosted undergraduate student researcher Chen Ji from Zhejiang University for the summer of 2012 as well as visiting scholar Kawa Ali from Salahaddin University in summer and fall of 2012. Offer a new course Molecular Plant Breeding (MPB) targeted at graduate students and international scientists interested in plant breeding program at MSU. Accomplishments: The Molecular Plant Breeding short course was first offered at MSU in September 2009. Since then, the course was offered on an annual basis at MSU as well as in international setting and has attracted plant breeders, researchers, academics as well as students from 31 countries around the world. With the cost of sequencing genomes becoming cheaper, over the past five years, there has been an increase in the use of molecular markers in plant breeding programs. With the availability of genome sequences, there has also been an increase in the use of SSR and SNP markers (compared to those that did not require sequence information for development and were not as robust) for marker assisted parent selection (MAPS) and marker assisted seedling selection (MASS). This change was also fueled by the support provided by USDA-NIFA through a number of Coordinated Agricultural Projects (CAPs) that brought together crop-based communities in the US for the use of genomic discoveries in marker development and use in plant breeding efforts. With the CAP projects well under way, the new plant breeding students and the community needed training not only in marker development approaches using the new genomic tools but also in how to validate genetic tests for MAPS and MASS. Therefore, over the years, there has been a significant improvement in the course content of the Molecular Plant Breeding short course reflecting this change to prepare the next generation of plant breeders and bridge the chasm between genomic discoveries and plant breeding efforts. For example, over the past several years, we witnessed an increase in the use of QTL information being used in plant breeding efforts. Therefore, a new session on “What it takes to move QTL from publications to applications” was added to the short course content last year. More information on the course content can be found on the World Technology Access Program (WorldTAP) website at http://worldtap.msu.edu/mpb/. Offering the course in international settings has given us insight into how to demystify misconceptions about marker-assisted breeding (MAB). Most think that identifying a QTL for a trait is marker-assisted breeding (MAB). They often forget that for MAB, QTL needs to be validated and genetic tests need to be developed before MAB can take place. Many are under the impression that they themselves have to develop all markers before use and it is too expensive and need sophisticated laboratory facilities for MAB. They often forget that once a genetic test is developed and validated for MAB, use of these tests for MAB is simple and there are service providers who could run the test for their breeding populations. We make sure that the participants of the course understand that it is marker development that is costly – not the application. Some believe MAB can replace traditional breeding methods and often forget a breeder needs to select for a number of traits to produce a winner cultivar that growers, packers, shippers, as well as consumers are willing to accept and that MAB is only a tool to increase the efficiency of plant breeding programs. They also forget that MAB is profitable when selecting for those traits where phenotypic selection alone can be misleading. Visits to MSU plant breeding programs (potato, soybean, and common bean) help participants understand the challenge breeders face in trying to develop a variety that is accepted throughout the value chain. These are some of the misconceptions that the course tries to address as the material is being covered. Given the participants are from various backgrounds and work with a number of different crops, we continued to allow each participant deliver a 10 minute presentation about the crop they work with and if MAB can assist improve the efficiency of their crop improvement program. These presentations gave participants an opportunity to learn from each other about challenges they face in plant breeding efforts. The course evaluation recorded an average rating of 9.5 out of 10 for the question whether the course met the expectations of the participants. How have the results been disseminated to communities of interest? Journal publications, presentations What do you plan to do during the next reporting period to accomplish the goals?
Nothing Reported
Impacts
What was accomplished under these goals?
Accomplishments: Over the course of the grant, we investigated the physiological responses to drought stress in several different bean varieties and how this response differed among varieties. Among the lines investigated were several varieties of common bean, and a variety of tepary bean, Phaseolus acutifolius. Using gas exchange measurements, we examined the rates of photosynthesis and conductance of bean plants exposed to well-watered control conditions and plants exposed to drought stress. The more drought tolerant varieties, such as SER-16 and tepary bean, had lower rates of photosynthesis and conductance under well-watered conditions compared to elite varieties like Jaguar, which is especially drought susceptible, and Zorro black bean. When these same varieties were exposed to progressively increasing drought stress, the drought tolerant varieties perceived the drought stress sooner in the dry down process and closed their stomata earlier than the elite varieties. With closed stomates, the tolerant varieties’ conductance and photosynthesis rates decreased further, and they conserved more water. These results suggest that drought tolerant varieties follow a conservative strategy toward managing stress: although they may not be as productive as elite varieties under ideal conditions, tolerant varieties are primed and quicker to respond to a drought event. As compatible solutes play a role in adjusting water potentials and protecting cellular components under time of stress, we investigated their concentration in bean plants exposed to drought stress. Although the amino acid proline accumulates in response to drought in certain plant species, in bean plants the levels of free proline did not differ between control and drought-treated plants. When examining sugars and organic acids like malic acid, fructose, glucose, and sucrose, their concentration in leaf tissues was significantly greater in drought-stressed plants than in control plants. The varieties tepary and Zorro accumulated more sugars and organic acids under drought stress than the varieties Jaguar and SER-16. This pool of sugars and organic acids could allow them to osmotically adjust their tissues under stress and provide them with a ready source of energy to help them recover after the passage of the stress. Consistent with their higher accumulation of sugars and organic acids, the leaf water potentials of tepary and Zorro were more negative under drought stress than the other varieties. Heat stress is similar to and shares some of the same response mechanisms with drought stress, and the two are often coincident in the field, so we investigated the bean varieties’ responses to progressively increasing temperatures over the course of weeks. The chlorophyll fluorescence parameter photosystem II efficiency was higher in the variety Jaguar than the other varieties under all temperature regimes. This difference means that Jaguar was dissipating less of its absorbed energy as fluorescence. A thiobarbituric acid reactive substances assay on bean leaves showed an increase in reactive oxygen species activity as the temperature increased, which would indicate an increase in oxidative stress caused by the heat. While there were no differences among the common bean varieties at any given temperature regimes, the tepary bean variety showed a higher concentration of thiobarbituric acid reactive substances at all temperature treatments. Measures of electrolyte leakage indicated that Jaguar’s cellular membranes were more disrupted at higher temperatures compared to the other bean varieties. Although tepary’s electrolyte leakage was initially high at the lower temperatures, this parameter was unaffected as the temperature increased, suggesting tepary’s ability to better withstand the stress it was facing. At the end of a week of forty degrees Celsius temperatures, the tepary and SER-16 varieties recovered when the temperature was lowered to twenty-five degrees Celsius and continued to live and grow. Jaguar and Zorro did not recover under the same conditions; the majority of those plants died when exposed to such high temperatures. Overall, the varieties tended to respond to heat stress in the same fashion as they responded to drought stress. Tepary and SER-16 followed a more conservative, adaptable strategy while Zorro and Jaguar followed a faster-growing, less responsive strategy. Abscisic acid is a major plant hormone key to drought signaling. After spraying the plants with solutions containing increasing concentrations of abscisic acid and measuring conductance, variety SER-16 severely closed its stomates at lower concentrations of abscisic acid than Jaguar or Zorro. These results suggest that SER-16 is more sensitive to abscisic acid exposure, and more broadly, that significant differences to abscisic acid responsiveness exist among the common bean germplasm. These data were presented as a poster at the American Society of Horticultural Sciences Meeting in Palm Desert CA. A second study was conducted to determine shoot traits that are associated with drought tolerance in common bean seedlings. Ten bean genotypes consisting mainly of cultivars and breeding lines from Mesoamerican race of the Middle American gene pool were first evaluated in the greenhouse. Genotypes were grown in a shallow soil profile to limit root growth and assess shoot phenotypes under stress. Water stress was imposed by withholding watering for 24 days after planting. Traits evaluated included wilting, unifoliate senescence, stem greenness, and recovery from drought. Biomass and number of pods/plant produced after drought recovery were evaluated to quantify the effect of early drought stress on bean growth and reproduction. A second group of 94 bean genotypes from the Bean Coordinated Agricultural Project (BeanCAP) were evaluated using the same protocol to determine the genetic variability for the same traits in a wider range of genotypes. In general, genotypes known to possess drought avoidance in the field conferred by deep rooting traits performed poorly in these conditions suggesting that the assay could be used to identify seedling shoot traits that contribute to drought tolerance. Genotypes from race Mesoamerica showed the greatest range in wilting. Genotypes that showed a slow rate of wilting, maintained a green stem, and had a higher recovery rate following watering. Importantly, these genotypes demonstrated a smaller reduction in biomass and pod number under stress compared to non-stress treatments. A few genotypes recovered completely despite expressing severe wilting whereas the majority of genotypes with high wilting rates did not recover. Among the BeanCAP materials, genotypes bred in the rainfed Midwestern U.S. showed overall better recovery than those bred under the irrigated production system used in the western U.S. Since recovery from drought is a prerequisite to plant regrowth, biomass, and pod production following drought stress, factors that contribute to recovery were studied. Stem greenness was highly positively correlated to the recovery while wilting was negatively correlated to the recovery. In a regression analysis, stem greenness and slow wilting were found to be important contributors to the variability of recovery. In addition, photosynthetic rate and stomatal conductance explained variation in wilting and stem greenness. These results suggest that wilting and stem greenness might be useful traits to screen for drought tolerance in seedlings of common bean. These data were summarized in paper by Mukeshimana et al., 2014 in JASHS.
Publications
- Type:
Journal Articles
Status:
Published
Year Published:
2014
Citation:
Mukeshimana, G., L. Butare, P.B. Cregan, M. W. Blair and J. D. Kelly. 2014. Quantitative Trait Loci associated with drought tolerance in common bean. Crop Sci. 54:923-938. doi:10.2135/cropsci2013.06.0427
- Type:
Journal Articles
Status:
Awaiting Publication
Year Published:
2014
Citation:
Mukeshimana, G., A.L. Lasley, W.H. Loescher and J.D. Kelly. 2014. Identification of shoot traits related to drought tolerance in common bean seedlings. J. Amer. Soc. Hort. Sci.139: (in press).
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2013
Citation:
Traub J, Kelly J, Loescher W. 2013. Varietal differences in physiology of drought stressed Phaseolus. Poster session presented at: American Society for Horticultural Science Annual Conference; July 22-25; Palm Desert, California.
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Progress 02/01/12 to 01/31/13
Outputs
Target Audience: Bean Scientists Changes/Problems:
Nothing Reported
What opportunities for training and professional development has the project provided? Two students graduated - one with MS and one with PhD How have the results been disseminated to communities of interest? yes- annual Horticulture meetings What do you plan to do during the next reporting period to accomplish the goals?
Nothing Reported
Impacts
What was accomplished under these goals?
Varietal differences in physiology of drought stressed Phaseolus Common bean (Phaseolus vulgaris) is the world’s most important directly consumed food legume; however, in many areas of the world bean production is drought limited, and this is a particular food security problem in the developing world. In an effort to improve the efficiencies of breeding for drought tolerance, we have compared various drought tolerance mechanisms in a broad range of Phaseolus genotypes from Andean, Mesoamerican, and Sonoran populations, from both P. vulgaris (common bean) and P. acutifolius (tepary bean), that are known to exhibit significant differences in drought tolerance in field trials. Mesoamerican and tepary bean genotypes are commonly recognized as generally more drought tolerant and more productive under moderate levels of stress when compared to Andean populations. Although these differences have often been attributed to root architecture, our studies of gas exchange, fluorescence parameters, and growth data show that under root limited conditions there are major differences related to several shoot factors, including heat tolerance, photosynthetic capacity, stomatal behavior and conductance. Some genotypes, for example, show evidence of osmoregulation (accumulation of several compatible solutes), particularly when water stressed, allowing for the maintenance of lower leaf water potentials. Other characteristics include more rapid stomatal closure when stressed and higher water use efficiencies, i.e., the ability to maintain photosynthesis as transpiration is decreasing. A/Ci analyses also show that the higher photosynthetic rates under both stress and well watered conditions are primarily due to differences in the generation of ribulose bisphosphate for the Calvin-Benson cycle. These results suggest several productive strategies to improving drought tolerance in common bean.
Publications
- Type:
Theses/Dissertations
Status:
Accepted
Year Published:
2013
Citation:
Lasley, A.L. 2013. Evaluation of root traits associated with drought tolerance in common bean (Phaseolus vulgaris L.). Masters Thesis, Michigan State University, East Lansing MI. 116pp.
Mukeshimana, G. 2013. Dissecting the genetic complexity of drought tolerance mechanisms in common bean (Phaseolus vulgaris L.). Doctoral Dissertation, Michigan State University, East Lansing MI. 210pp.
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Progress 02/01/11 to 01/31/12
Outputs
OUTPUTS: To develop expanded greenhouse phenotypic screening protocols for drought resistance in common bean: Eight dry bean genotypes with known tolerance to drought in the field were evaluated in small 9 cm2 pots in the greenhouse to measure recovery from a 2-week period without watering. The root was constrained in this system to investigate shoot mechanisms underlying drought resistance in bean seedlings. Parameters measured were wilting, unifoliate senescence, stem greenhouse, recovery after resuming watering, plant biomass, pod and seed numbers. Certain cultivars did not show any significant difference in pod number under both drought stress and root restrictions, whereas others showed significant reduction in pod numbers, suggesting that they rely more on root traits to sustain them through prolonged periods of drought in the field. In other root growth restriction experiments, four different dry bean varieties grown in similar pots in growth chambers were also measured for photosynthesis and conductance rates as determined via gas exchange measurements. Three-week old plants were either kept in a well-watered condition or exposed to drought stress by withholding water, and measurements were taken when plants reached a set pot weight. Differences in photosynthesis among the four varieties were found in both well-watered and drought treatments. Higher rates of photosynthesis during drought correlated with greater above ground biomass dry weight. Ninety-six bean genotypes from the BeanCAP project (http://www.beancap.org/) specifically selected for drought evaluation, were grown in the field in Michigan in 2011. When fifty percent of the genotypes were flowering, five plants from each plot were excavated and data was recorded for: basal root angles, basal root branching in a three centimeter segment, number of basal roots, number of adventitious roots, adventitious root branching in a three centimeter segment, tap root diameter, tap root branching in a three centimeter segment, an overall root score, and dry weight of shoots and roots. At the end of the season, total plant biomass was recorded before threshing. Throughout the growing season, other data taken included: flowering date, maturity date, lodging, height, seed weight and yield. The root data will be compared with performance data for MI but from five other locations in the US where the same beancap trial was grown under drought stress. Molecular Plant Breeding (MPB) short course targeted at graduate students and international scientists interested in plant breeding program at MSU was offered for in 2011. This course was attended by 13 participants representing ten countries (China, Colombia, Ethiopia, Ghana, India, Sri Lanka, Taiwan, Tanzania, Uganda, and USA). Participants of the course were from various backgrounds including three graduate students of the Plant Breeding, Genetics and Biotechnology (PBGB) program, visiting scholars and international participants. Among the group were six professional plant breeders (Rice, Tef, Cassava, Soybean, Okra and Pea) from Asia and Africa. PARTICIPANTS: Graduate student Valerio Hoyos joined the program as a doctoral candidate in 2011 and Valerio participated in Molecular Plant Breeding short course. He will evaluate genotypes from the BeanCAP for reaction to drought. Two graduate students Amy Lasley and Jesse Traub are actively working on research related to this project.Gerardine Mukeshimana, doctoral student participated in 2-week workshop on Breeding for Drought Tolerance held at Colorado State Univ in June, 2010.Three undergraduate students, Riley Marshall, Mary Marshall and Cindy Amstutz assisted in the program, conducting bean hybridization, DNA extraction, running SCAR and RAPD markers, and disease screening. We are exploring possible new funding opportunities to work on drought stress in bean in collaboration with Dr. Steve Beebe at CIAT, Colombia to further drought research in Rwanda. In addition we have had discussions with Dr. Liz Van Volkenburgh at the University of Washington on ways to collaborate on research on photosynthesis of beans under drought stress. Student research projects will involve study of photosynthetic traits under stress; and evaluating bean genotypes from the BeanCAP project for drought and determination of additional physiological parameters that could be used in field screening for drought. TARGET AUDIENCES: J.D. Kelly presented research on breeding beans for rainfed conditions in the US and participated in workshop on Improving Tolerance of Common Bean to Abiotic Stresses, at the International Center-CIAT, Cali Colombia, 2-4 November, 2010. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.
Impacts
Michigan is the second largest producer of dry bean in the U.S. Over 90% of bean acreage is grown under rainfed conditions in the Great Lakes watershed. Finding bean germplasm and varieties with enhanced level of resistance to drought is critical to sustain the bean industry in the state as summer rainfall patterns over the last decade continue to diminish in quantity and regional distribution. Bean genotypes with improved water use efficient would be valuable in irrigated areas in the western US where water costs are increasing and its availability for irrigation is more restrictive. One of the most drought tolerant bean cultivars Zorro black bean identified in this study is now grown on over 50% acreage in Michigan.
Publications
- Acosta-Gallegos, J., J.D. Kelly. 2012. Strategies to improve adaptation of common bean to drought. Ann. Rept. Bean Improv. Coop. 55:7-8. Mukeshimana, G., L. Butare, S. Beebe, M.W. Blair and J.D. Kelly. 2012. Phenotypic evaluation of dry bean RIL populations for drought resistance in Rwanda. Ann. Rept. Bean Improv. Coop. 55:111-112.
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Progress 02/01/10 to 01/31/11
Outputs
OUTPUTS: The 2010 season proved to be an excellent screening nursery for drought in Michigan, as bean plots received only 85 mm of rainfall during the growing season compared to normal precipitation of 240 mm for the same period. Yields were reduced by 53 percent across all trials, but yield losses for individual genotypes ranged from 40 to 77 percent and permitted the identification of lines with higher levels of drought resistance in the field. The new black bean variety Zorro showed less reduction in yield due to drought compared to the other 400 bean lines in trial. A group of 375 single row plots grown as part of the BeanCAP project were also evaluated for adaptation. Eight dry bean genotypes with known tolerance to drought in the field were evaluated in 9 cm2 pots in the greenhouse to measure recovery from a 2-week period without watering. The root was constrained in this system to investigate shoot mechanisms underlying drought resistance in bean seedlings. Parameter measured were wilting, unifoliate senescence, stem greenhouse, recovery after resuming watering, plant biomass, pod and seed numbers. Certain cultivars did not show any significant difference in pod number under both drought stress, whereas others showed significant reduction in pod numbers, suggesting that they rely more on root traits to sustain them through prolonged periods of drought in the field. Work continues to develop a transformation system for Phaseolus beans. Three strains of Agrobacterium tumefaciens were evaluated for ability to infect common bean using GUS transient expression. Different bean genotypes were very susceptible to these strains and a few kanamycin-resistant calluses were produced that showed strong GUS staining. Efforts to induce plant regeneration from these transgenic calluses involved five transformation experiments each with about 200 explants. One protocol produced resistant calluses followed by regeneration through somatic embryogenesis. Five out of 36 callus clusters had regeneration after transferring into regeneration medium containing 100 mg/L kanamycin. Research was conducted to investigate methods to reduce recalcitrance of common bean towards in vitro regeneration. Results showed that a ratio of 2.5 mg/L benzyladenine to 0.1 mg/L of naphthalene acetic acid or indole-3-acetic acid promoted robust multiple shoot regeneration. The addition of 30 mg/L of silver nitrate reduced the inhibitory effect of phenolic compounds. PARTICIPANTS: James D. Kelly, Wayne Loescher, Cholani Weebadde, Guo-qing Song TARGET AUDIENCES: Bean farmers, bean elevator managers in Michigan, Bean geneticists and physiologists. PROJECT MODIFICATIONS: None.
Impacts
In Michigan, the adoption of new upright black bean variety Zorro from MSU breeding program showed excellent drought tolerance in addition to providing growers with opportunity to direct harvest the crop and thus reduce production costs.
Publications
- Kwapata, K., Sabzikar, R., Sticklen, M.B. and Kelly, J.D. 2010. In vitro regeneration and morphogenesis studies in common bean. Plant Cell Tiss. Organ. Cult.: J. Plant Biotechnology. 100:97-105.
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