Cyanobacteria possess an inducible mechanism which enables them to concentrate inorganic carbon (... more Cyanobacteria possess an inducible mechanism which enables them to concentrate inorganic carbon (Ci) within the cells. An inactivation library was used to raise the high-CO Prequiring mutant of Synechococcus PCC 7942, IL-2, impaired in rgy 3 3 transport. Analysis of the relevant genomic DNA detected several modifications, probably due to the single crossover recombination, leading to inactivation of ORF467 (designated ictB) in IL-2. IctB contains 10 trans-membrane regions and is homologous to several transport-related proteins from various organisms. Kinetic analyses of rgy 3 3 uptake in the wild type and IL-2 suggested the presence of two or three rgy 3 3 carriers exhibiting different affinities to rgy 3 3 .
Modifying plant architecture is considered a promising breeding option to enhance crop productivi... more Modifying plant architecture is considered a promising breeding option to enhance crop productivity. Modern chickpea (Cicer arietinum L.) cultivars with either compound (wild-type) or simple leaf shapes are commercially grown but the relationships between leaf shape and yield are not well understood. In this study, a random sample of 'Kabuli' type progeny lines of both leaf types, derived from two crosses between modern American simple leaf cultivars and early-flowering wild-type breeding lines, were planted at different sowing densities. Leaf area development and final grain yield in genotypes of the two leaf types responded differently to changes in sowing densities. Compound leaf lines attained higher leaf area indices and higher grain yields at both low and high sowing densities. Yield responses of the simple leaf lines to increasing sowing density were significantly higher compared to compound leaf genotypes in two of three field experiments. The prospects for utilizing the simple leaf trait as a breeding target for short-season growing areas are discussed.
Evidence from an array of dryland systems suggests that chickpea (Cicer arietinum L.) grain yield... more Evidence from an array of dryland systems suggests that chickpea (Cicer arietinum L.) grain yield could be improved through better phenological adaptation. However, information on the relationship between phenology and Ascochyta response genes, and their possible interaction with biomass and grain yield, is missing. Accordingly, the aim of the present study was to determine the associations between the above factors and biomass and grain yield in chickpea. To that end, standard Israeli cultivars and advanced generation bulked progeny from the cv. Hadas × ICC5810 cross were used. Hadas is a late-flowering, high-yielding Israeli kabuli (0.45 g/seed) cultivar with moderate field resistance to Ascochyta blight, whereas ICC5810 is a day-neutral desi (0.15 g/seed) genotype with a strong temperature response, from India. Higher yields were observed among the late-flowering bulks of the Hadas × ICC5810 progeny. No relationship between the Ascochyta response and biomass and grain yield was observed. No interaction between the phenology and Ascochyta response grouping on biomass and grain yield was observed. The results demonstrate the feasibility of combining Ascochyta resistance with earlier flowering and its potential to improve chickpea adaptation to dryland systems.
Terminal drought is a major constraint to chickpea (Cicer arietinum L.) production. Autumn sowing... more Terminal drought is a major constraint to chickpea (Cicer arietinum L.) production. Autumn sowing and early flowering have been suggested as ways to benefit from the winter rains in short rainy seasons under dryland cropping. High-yielding, late-flowering, simpleleafed (slv/slv) chickpea cultivars with good field resistance to Ascochyta blight have been bred recently. Changing plant architecture, by altering leaf shape, may affect agronomic performance. As no information is available on the effect of leaf shape on phenology and seed yield, this study was aimed at: (i) introducing the simple leaf trait into an early-flowering chickpea background; (ii) comparing the grain yield of the two leaf types in early vs. late flowering backgrounds and (iii) producing breeding lines combining early flowering, large seeds and Ascochyta tolerance with both leaf types. Hybrid progeny were studied from the cross of ÔSanfordÕ (slv/slv) and ICC7344, (compound, SLV/SLV). Four early-podding, F 8 breeding lines were selected with either simple or compound leaves. In three different field experiments under dryland conditions (334-379 mm), they yielded ca. 1.4 t/ha as compared with 1.0 t/ha in the standard Israeli ÔYardenÕ on one site, but no significant differences in yield were obtained in the other two experiments.
Chickpea yields in Israel are usually considerably lower than wheat yields under comparable condi... more Chickpea yields in Israel are usually considerably lower than wheat yields under comparable conditions. This study aimed to examine the possible yield limiting factors in chickpeas. Increasing the availability of nitrogen during seed development by a pre-sowing application of nitrate or by nitrogen top dressing at the onset of flowering led to an increase in the percentage of nitrogen in the straw but had no significant effect on seed yield. Growth analysis of chickpeas and wheat grown in two adjacent field experiments revealed that during the fruiting period these crops accumulated similar amounts of dry matter. However, the proportion of total wheat dry matter accumulated in the wheat grains was twice the proportion of total chickpea dry matter accumulated in the chickpea seeds. It was concluded that the main intrinisic factor limiting the seed yield of chickpeas is the continuation of vegetative growth during the period of seed development, which reduces the amount of assimilate allocated to the seeds. Los/adores restrictivos del rendimiento en el garbanzo RESUMEN El rendimiento del garbanzo en Israel es normalmente menor que el del trigo en condiciones comparables. Este estudio pretendfa examinar los posibles factores restrictivos del rendimiento de los garbanzos. El aumentar la disponibilidad de nitrogeno durante el desarrollo de la semilla mediante una aplicacion de nitrato previa a la siembra, o mediante una capa superior de nitrogeno al comienzo de la floracion llevo a un incremento en el porcentaje de nitrogeno en la paja pero no tuvo ningun efecto significativo en el rendimiento de la semilla. Un analisis de crecimiento de garbanzos y trigo, cultivados en dos experimentos en campos adyacentes, revelo que durante el periodo de fructification estos cultivos acumularon cantidades similares de materia seca. No obstante, la proporcion de materia seca de trigo acumulada en los granos de trigo doblo la proporcion total de materia seca de garbanzos acumulada en las semillas de garbanzos. Se concluyo que el principal factor intrinseco que restringia el rendimiento de las semillas de garbanzos es la continuation de crecimiento vegetativo durante el periodo de desarrollo de la semilla, lo que reduce la cantidad de glucosa distribuida a las semillas.
bioRxiv (Cold Spring Harbor Laboratory), Feb 13, 2023
Context: While the world population is steadily growing, the demand for plant-based protein in ge... more Context: While the world population is steadily growing, the demand for plant-based protein in general, and chickpea in particular, is rising. Heatwaves and terminal drought are the main abiotic factors limiting chickpea yield worldwide. Objective: Developing better irrigation management for the chickpea agro-system can promote higher and more sustainable yields. Supplemental irrigation at the right timing and dose may increase yield dramatically. Methods: We studied the response of a modern Kabuli chickpea cultivar to irrigation during the pod-filling period over three growing seasons (2019-2021) in northern Negev, Israel, under semiarid conditions. Six irrigation treatments were applied based on crop coefficients (Kc) of 0, 0.5, 0.7, 1.0, 1.25, and 1.4 of crop evapotranspiration (ETc) as measured by a meteorological station on site. Morpho-physiological parameters and above-ground biomass accumulation were monitored throughout the cropping seasons, and the final grain yield was determined at maturation. Irrigation onset was determined based on the plants' water potential (> 15 bar). Results: Our results indicate that optimal water status (as reflected by pressure chamber values) was in the range of 12-14 bar during the irrigation period. Irrigation according to evapotranspiration (ETc) with a crop coefficient factor (Kc) of 1.25 resulted in the highest grain yields over the three years. To ensure optimal water supply during the reproductive phase, one that is compatible with the crop water requirements, maintaining values of 25 mm node length above the Last Fully Developed Pod (LFDP) and a 90 mm distance between LFDP to the stem apex is recommended. Conclusions: Irrigation onset when the crop is already at mild drought stress, followed by sufficient irrigation while following the indicated morphology and water potential values, may help farmers optimize irrigation and maximize chickpea crop production.
An inactivation library consisting of genomic fragments ligated within a modified bluescript vect... more An inactivation library consisting of genomic fragments ligated within a modified bluescript vector was used to isolate several new high CO2 requiring mutants of Synechococcus PCC7942. The mutants described here were impaired in the ability to accumulate Ci internally when supplied with HCO3-. The relevant genomic regions bearing novel genes involved in the ability to transport and to accumulate Ci within the cells and thus to grow under low-CO2 conditions are presented. Some of the mutants were also impaired in ability to adjust to an elevated pH in their medium. We show that the use of inactivation libraries enabled cloning of genes encoding membrane-located proteins; we point to mutations introduced by the single cross-recombination events resulting in the formation of some of these mutants. Possible artifacts that may result in incorrect identification of genes, the inactivation of which could have led to the observed phenotype, are discussed.Key words: bicarbonate uptake, cyanobacteria, CO2, mutants, photosynthesis, Synechococcus.
The spectral‐based photochemical reflectance index (PRI) and leaf surface temperature (Tleaf) der... more The spectral‐based photochemical reflectance index (PRI) and leaf surface temperature (Tleaf) derived from thermal imaging are two indicative metrics of plant functioning. The relationship of PRI with radiation‐use efficiency (RUE) and Tleaf with leaf transpiration could be leveraged to monitor crop photosynthesis and water use from space. Yet, it is unclear how such relationships will change under future high carbon dioxide concentrations ([CO2]) and drought. Here we established an [CO2] enrichment experiment in which three wheat genotypes were grown at ambient (400 ppm) and elevated (550 ppm) [CO2] and exposed to well‐watered and drought conditions in two glasshouse rooms in two replicates. Leaf transpiration (Tr) and latent heat flux (LE) were derived to assess evaporative cooling, and RUE was calculated from assimilation and radiation measurements on several dates along the season. Simultaneous hyperspectral and thermal images were taken at 1.5 m from the plants to derive PRI and the temperature difference between the leaf and its surrounding air (Tleaf−air). We found significant PRI and RUE and Tleaf−air and Tr correlations, with no significant differences among the genotypes. A PRI–RUE decoupling was observed under drought at ambient [CO2] but not at elevated [CO2], likely due to changes in photorespiration. For a LE range of 350 W m–2, the ΔTleaf−air range was 10°C at ambient [CO2] and only 4°C at elevated [CO2]. Thicker leaves in plants grown at elevated [CO2] suggest higher leaf water content and consequently more efficient thermoregulation at high [CO2] conditions. In general, Tleaf was maintained closer to the ambient temperature at elevated [CO2], even under drought. PRI, RUE, ΔTleaf−air, and Tr decreased linearly with canopy depth, displaying a single PRI‐RUE and ΔTleaf−air Tr model through the canopy layers. Our study shows the utility of these sensing metrics in detecting wheat responses to future environmental changes.
Staple food fortification is a rational and economic way to improve the health status of poor inc... more Staple food fortification is a rational and economic way to improve the health status of poor income consumers. Lutein is an important antioxidant, and its intake is associated with lower risk of macular degeneration (blindness). We studied the scope to improve lutein concentration in chickpea grains by routine farming practices including tillage, and phosphorus and potassium fertilization. In addition, the association between lutein concentration and grain weight was investigated. The genetic (cultivar) effect on lutein concentration greatly exceeded the husbandry effects. High-lutein concentration in chickpea grains was recessive to low-lutein concentration. High-lutein concentration in the studied material was associated with low-grain weight, similar to results obtained from crosses involving wild chickpea. Breeding large seeded chickpea with enhanced lutein concentration may be difficult due to the association of lutein promoting alleles with low-grain weight alleles. However, our results confirm that chickpea grain lutein concentration trait is relatively stable, due to strong genetic control. Therefore, high-lutein cultivars are likely to maintain their performance even when grown under diverse field conditions.
sampled during the drought and following recovery. Metabolite profiles were generated using a GC-... more sampled during the drought and following recovery. Metabolite profiles were generated using a GC-MS based protocol. Data on transpiration were continually acquired by measuring the weight variation of pots using electronic temperature compensated load cells. Results The tillering stage in wheat is more sensitive to droughts than the grain filling stage. The former stage was characterized by pronounced metabolic alterations also during recovery from the drought, and plants exhibited reduced transpiration. Notably, cultivars varied considerably in their susceptibility to drought. Exceptionally only in cv Zahir was transpiration not reduced at tillering. During recovery, the transpiration rate of Yuval and Zahir was not significantly affected, while except Ruta the other varieties maintained lower values. At grain-filling, a moderate decrease in transpiration in response to drought was evident in Bar-Nir, Yuval and Zahir varieties as compared with the stronger response of Gedera, Galil and Ruta. The transpiration trend during recovery remained lower than the control plants, particularly in Gedera and Zahir, while it reached higher values Abstract Introduction Mediterranean winter crops are commonly and increasingly exposed to irregular rainfall and high temperatures, which lead to transient drought events of different degrees, adversely affecting growth and yield. Hence, exploring the diverse degrees of tolerance to drought existing in the crop and the molecular strategies behind it is pivotal for the development of ad hoc breeding programs. Objective We investigated the physiological and metabolic response of six commercial wheat cultivars to transient water stress at the tillering and grain-filling stages. Methods Drought experiments in lysimeters were set up at two developmental stages including six wheat cultivars. Newly expanded youngest leaves and flag leaves were Moses Kwame Aidoo and Lydia Quansah have contributed equally to the study.
IntroductionDuring the 20th century, the worldwide genetic diversity of wheat was sharply eroded ... more IntroductionDuring the 20th century, the worldwide genetic diversity of wheat was sharply eroded by continual selection for high yields and industry demands for particular standardized qualities. A collection of Israeli and Palestinian landraces (IPLR) was established to represent genetic diversity, accumulated for ten millennia under diverse environments, which was mostly lost in this transition. As our long-term goal is to study this pre- Green Revolution genetic reservoir, herein we focus on its flour and bread quality and sensorial attributes.MethodsInitially, a database was built for the entire IPLR collection (n=901) holding both Triticum durum (durum wheat) and T. aestivum (bread wheat) which included genetic and phenotypic characterization of agronomic traits, grain and flour quality. Then, a representative subset of the IPLR was selected and compared to modern varieties for dough quality, rheology, aroma and taste using both whole and refined flours and breads. The sensory ...
The rising demand for spelt wheat (Triticum aestivum ssp. spelta) as a high-value grain crop has ... more The rising demand for spelt wheat (Triticum aestivum ssp. spelta) as a high-value grain crop has raised interest in its introduction into non-traditional spelt growing areas. This study aimed to assess adaptive constrains of spelt under short Mediterranean season. At first screening of a wide spelt collection for phenology and allelic distribution at the photoperiod (PPD) and vernalization (VRN) loci was done. In addition an in-depth phenotypic evaluation of a selected panel (n = 20) was performed, including agronomically important traits and concentration of grain mineral (GMC) and grain protein (GPC) content. Results from both wide screening and in-depth in panel (group of 18 spelt lines and two bread wheat lines) evaluation shows that the major adaptive constraint for spelt under Mediterranean conditions is late heading, caused by day length sensitivity, as evident from phenology and allelic profile (PPD and VRN). All lines carrying the photoperiod-sensitive allele (PPD-D1b) were...
Journal of the Science of Food and Agriculture, 2019
BACKGROUNDFor over a century, genetic diversity of wheat worldwide was eroded by continual select... more BACKGROUNDFor over a century, genetic diversity of wheat worldwide was eroded by continual selection for high yields and industrial demands. Wheat landraces cultivated in Israel and Palestine demonstrate high genetic diversity and a potentially wide repertoire of adaptive alleles. While most Israeli‐Palestinian wheat landraces were lost in the transition to ‘Green Revolution’ semi‐dwarf varieties, some germplasm collections made at the beginning of the 20th century survived in gene banks and private collections worldwide. However, fragmentation and poor conservation place this unique genetic resource at a high risk of genetic erosion. Herein, we describe a long‐term initiative to restore, conserve, and characterize a collection of Israeli and Palestinian wheat landraces (IPLR).RESULTSWe report on (i) the IPLR construction (n = 932), (ii) the historical and agronomic context to this collection, (iii) the characterization and assessment of the IPLR's genetic diversity, and (iv) a ...
The increasing demand for spelt products requires the baking industry to develop accurate and eff... more The increasing demand for spelt products requires the baking industry to develop accurate and efficient tools to differentiate between spelt and bread wheat grains. We subjected a 272-sample spelt-bread wheat set to several potential diagnostic methods. DNA markers for γ-gliadin-D (GAG56D), γ-gliadin-B (GAG56B) and the Q-gene were used, alongside phenotypic assessment of ease-of-threshing, and Near-infrared spectroscopy (NIRS). The GAG56B and GAG56D markers demonstrated low diagnostic power in comparison to the Q-gene genotyping, which showed full accordance with the threshing phenotype, providing a highly accurate distinction between bread wheat and spelt kernels. A highly reliable Q classification was based on a three-waveband NIR model [Kappa (0.97), R-square (0.93)], which suggested that this gene influences grain characteristics. Our data ruled out a protein concentration bias of the NIRS-based diagnosis. These findings highlight the Q gene and NIRS as important, valuable, but 14 simple tools for distinguishing between bread wheat and spelt.
Cyanobacteria possess an inducible mechanism which enables them to concentrate inorganic carbon (... more Cyanobacteria possess an inducible mechanism which enables them to concentrate inorganic carbon (Ci) within the cells. An inactivation library was used to raise the high-CO Prequiring mutant of Synechococcus PCC 7942, IL-2, impaired in rgy 3 3 transport. Analysis of the relevant genomic DNA detected several modifications, probably due to the single crossover recombination, leading to inactivation of ORF467 (designated ictB) in IL-2. IctB contains 10 trans-membrane regions and is homologous to several transport-related proteins from various organisms. Kinetic analyses of rgy 3 3 uptake in the wild type and IL-2 suggested the presence of two or three rgy 3 3 carriers exhibiting different affinities to rgy 3 3 .
Modifying plant architecture is considered a promising breeding option to enhance crop productivi... more Modifying plant architecture is considered a promising breeding option to enhance crop productivity. Modern chickpea (Cicer arietinum L.) cultivars with either compound (wild-type) or simple leaf shapes are commercially grown but the relationships between leaf shape and yield are not well understood. In this study, a random sample of 'Kabuli' type progeny lines of both leaf types, derived from two crosses between modern American simple leaf cultivars and early-flowering wild-type breeding lines, were planted at different sowing densities. Leaf area development and final grain yield in genotypes of the two leaf types responded differently to changes in sowing densities. Compound leaf lines attained higher leaf area indices and higher grain yields at both low and high sowing densities. Yield responses of the simple leaf lines to increasing sowing density were significantly higher compared to compound leaf genotypes in two of three field experiments. The prospects for utilizing the simple leaf trait as a breeding target for short-season growing areas are discussed.
Evidence from an array of dryland systems suggests that chickpea (Cicer arietinum L.) grain yield... more Evidence from an array of dryland systems suggests that chickpea (Cicer arietinum L.) grain yield could be improved through better phenological adaptation. However, information on the relationship between phenology and Ascochyta response genes, and their possible interaction with biomass and grain yield, is missing. Accordingly, the aim of the present study was to determine the associations between the above factors and biomass and grain yield in chickpea. To that end, standard Israeli cultivars and advanced generation bulked progeny from the cv. Hadas × ICC5810 cross were used. Hadas is a late-flowering, high-yielding Israeli kabuli (0.45 g/seed) cultivar with moderate field resistance to Ascochyta blight, whereas ICC5810 is a day-neutral desi (0.15 g/seed) genotype with a strong temperature response, from India. Higher yields were observed among the late-flowering bulks of the Hadas × ICC5810 progeny. No relationship between the Ascochyta response and biomass and grain yield was observed. No interaction between the phenology and Ascochyta response grouping on biomass and grain yield was observed. The results demonstrate the feasibility of combining Ascochyta resistance with earlier flowering and its potential to improve chickpea adaptation to dryland systems.
Terminal drought is a major constraint to chickpea (Cicer arietinum L.) production. Autumn sowing... more Terminal drought is a major constraint to chickpea (Cicer arietinum L.) production. Autumn sowing and early flowering have been suggested as ways to benefit from the winter rains in short rainy seasons under dryland cropping. High-yielding, late-flowering, simpleleafed (slv/slv) chickpea cultivars with good field resistance to Ascochyta blight have been bred recently. Changing plant architecture, by altering leaf shape, may affect agronomic performance. As no information is available on the effect of leaf shape on phenology and seed yield, this study was aimed at: (i) introducing the simple leaf trait into an early-flowering chickpea background; (ii) comparing the grain yield of the two leaf types in early vs. late flowering backgrounds and (iii) producing breeding lines combining early flowering, large seeds and Ascochyta tolerance with both leaf types. Hybrid progeny were studied from the cross of ÔSanfordÕ (slv/slv) and ICC7344, (compound, SLV/SLV). Four early-podding, F 8 breeding lines were selected with either simple or compound leaves. In three different field experiments under dryland conditions (334-379 mm), they yielded ca. 1.4 t/ha as compared with 1.0 t/ha in the standard Israeli ÔYardenÕ on one site, but no significant differences in yield were obtained in the other two experiments.
Chickpea yields in Israel are usually considerably lower than wheat yields under comparable condi... more Chickpea yields in Israel are usually considerably lower than wheat yields under comparable conditions. This study aimed to examine the possible yield limiting factors in chickpeas. Increasing the availability of nitrogen during seed development by a pre-sowing application of nitrate or by nitrogen top dressing at the onset of flowering led to an increase in the percentage of nitrogen in the straw but had no significant effect on seed yield. Growth analysis of chickpeas and wheat grown in two adjacent field experiments revealed that during the fruiting period these crops accumulated similar amounts of dry matter. However, the proportion of total wheat dry matter accumulated in the wheat grains was twice the proportion of total chickpea dry matter accumulated in the chickpea seeds. It was concluded that the main intrinisic factor limiting the seed yield of chickpeas is the continuation of vegetative growth during the period of seed development, which reduces the amount of assimilate allocated to the seeds. Los/adores restrictivos del rendimiento en el garbanzo RESUMEN El rendimiento del garbanzo en Israel es normalmente menor que el del trigo en condiciones comparables. Este estudio pretendfa examinar los posibles factores restrictivos del rendimiento de los garbanzos. El aumentar la disponibilidad de nitrogeno durante el desarrollo de la semilla mediante una aplicacion de nitrato previa a la siembra, o mediante una capa superior de nitrogeno al comienzo de la floracion llevo a un incremento en el porcentaje de nitrogeno en la paja pero no tuvo ningun efecto significativo en el rendimiento de la semilla. Un analisis de crecimiento de garbanzos y trigo, cultivados en dos experimentos en campos adyacentes, revelo que durante el periodo de fructification estos cultivos acumularon cantidades similares de materia seca. No obstante, la proporcion de materia seca de trigo acumulada en los granos de trigo doblo la proporcion total de materia seca de garbanzos acumulada en las semillas de garbanzos. Se concluyo que el principal factor intrinseco que restringia el rendimiento de las semillas de garbanzos es la continuation de crecimiento vegetativo durante el periodo de desarrollo de la semilla, lo que reduce la cantidad de glucosa distribuida a las semillas.
bioRxiv (Cold Spring Harbor Laboratory), Feb 13, 2023
Context: While the world population is steadily growing, the demand for plant-based protein in ge... more Context: While the world population is steadily growing, the demand for plant-based protein in general, and chickpea in particular, is rising. Heatwaves and terminal drought are the main abiotic factors limiting chickpea yield worldwide. Objective: Developing better irrigation management for the chickpea agro-system can promote higher and more sustainable yields. Supplemental irrigation at the right timing and dose may increase yield dramatically. Methods: We studied the response of a modern Kabuli chickpea cultivar to irrigation during the pod-filling period over three growing seasons (2019-2021) in northern Negev, Israel, under semiarid conditions. Six irrigation treatments were applied based on crop coefficients (Kc) of 0, 0.5, 0.7, 1.0, 1.25, and 1.4 of crop evapotranspiration (ETc) as measured by a meteorological station on site. Morpho-physiological parameters and above-ground biomass accumulation were monitored throughout the cropping seasons, and the final grain yield was determined at maturation. Irrigation onset was determined based on the plants' water potential (> 15 bar). Results: Our results indicate that optimal water status (as reflected by pressure chamber values) was in the range of 12-14 bar during the irrigation period. Irrigation according to evapotranspiration (ETc) with a crop coefficient factor (Kc) of 1.25 resulted in the highest grain yields over the three years. To ensure optimal water supply during the reproductive phase, one that is compatible with the crop water requirements, maintaining values of 25 mm node length above the Last Fully Developed Pod (LFDP) and a 90 mm distance between LFDP to the stem apex is recommended. Conclusions: Irrigation onset when the crop is already at mild drought stress, followed by sufficient irrigation while following the indicated morphology and water potential values, may help farmers optimize irrigation and maximize chickpea crop production.
An inactivation library consisting of genomic fragments ligated within a modified bluescript vect... more An inactivation library consisting of genomic fragments ligated within a modified bluescript vector was used to isolate several new high CO2 requiring mutants of Synechococcus PCC7942. The mutants described here were impaired in the ability to accumulate Ci internally when supplied with HCO3-. The relevant genomic regions bearing novel genes involved in the ability to transport and to accumulate Ci within the cells and thus to grow under low-CO2 conditions are presented. Some of the mutants were also impaired in ability to adjust to an elevated pH in their medium. We show that the use of inactivation libraries enabled cloning of genes encoding membrane-located proteins; we point to mutations introduced by the single cross-recombination events resulting in the formation of some of these mutants. Possible artifacts that may result in incorrect identification of genes, the inactivation of which could have led to the observed phenotype, are discussed.Key words: bicarbonate uptake, cyanobacteria, CO2, mutants, photosynthesis, Synechococcus.
The spectral‐based photochemical reflectance index (PRI) and leaf surface temperature (Tleaf) der... more The spectral‐based photochemical reflectance index (PRI) and leaf surface temperature (Tleaf) derived from thermal imaging are two indicative metrics of plant functioning. The relationship of PRI with radiation‐use efficiency (RUE) and Tleaf with leaf transpiration could be leveraged to monitor crop photosynthesis and water use from space. Yet, it is unclear how such relationships will change under future high carbon dioxide concentrations ([CO2]) and drought. Here we established an [CO2] enrichment experiment in which three wheat genotypes were grown at ambient (400 ppm) and elevated (550 ppm) [CO2] and exposed to well‐watered and drought conditions in two glasshouse rooms in two replicates. Leaf transpiration (Tr) and latent heat flux (LE) were derived to assess evaporative cooling, and RUE was calculated from assimilation and radiation measurements on several dates along the season. Simultaneous hyperspectral and thermal images were taken at 1.5 m from the plants to derive PRI and the temperature difference between the leaf and its surrounding air (Tleaf−air). We found significant PRI and RUE and Tleaf−air and Tr correlations, with no significant differences among the genotypes. A PRI–RUE decoupling was observed under drought at ambient [CO2] but not at elevated [CO2], likely due to changes in photorespiration. For a LE range of 350 W m–2, the ΔTleaf−air range was 10°C at ambient [CO2] and only 4°C at elevated [CO2]. Thicker leaves in plants grown at elevated [CO2] suggest higher leaf water content and consequently more efficient thermoregulation at high [CO2] conditions. In general, Tleaf was maintained closer to the ambient temperature at elevated [CO2], even under drought. PRI, RUE, ΔTleaf−air, and Tr decreased linearly with canopy depth, displaying a single PRI‐RUE and ΔTleaf−air Tr model through the canopy layers. Our study shows the utility of these sensing metrics in detecting wheat responses to future environmental changes.
Staple food fortification is a rational and economic way to improve the health status of poor inc... more Staple food fortification is a rational and economic way to improve the health status of poor income consumers. Lutein is an important antioxidant, and its intake is associated with lower risk of macular degeneration (blindness). We studied the scope to improve lutein concentration in chickpea grains by routine farming practices including tillage, and phosphorus and potassium fertilization. In addition, the association between lutein concentration and grain weight was investigated. The genetic (cultivar) effect on lutein concentration greatly exceeded the husbandry effects. High-lutein concentration in chickpea grains was recessive to low-lutein concentration. High-lutein concentration in the studied material was associated with low-grain weight, similar to results obtained from crosses involving wild chickpea. Breeding large seeded chickpea with enhanced lutein concentration may be difficult due to the association of lutein promoting alleles with low-grain weight alleles. However, our results confirm that chickpea grain lutein concentration trait is relatively stable, due to strong genetic control. Therefore, high-lutein cultivars are likely to maintain their performance even when grown under diverse field conditions.
sampled during the drought and following recovery. Metabolite profiles were generated using a GC-... more sampled during the drought and following recovery. Metabolite profiles were generated using a GC-MS based protocol. Data on transpiration were continually acquired by measuring the weight variation of pots using electronic temperature compensated load cells. Results The tillering stage in wheat is more sensitive to droughts than the grain filling stage. The former stage was characterized by pronounced metabolic alterations also during recovery from the drought, and plants exhibited reduced transpiration. Notably, cultivars varied considerably in their susceptibility to drought. Exceptionally only in cv Zahir was transpiration not reduced at tillering. During recovery, the transpiration rate of Yuval and Zahir was not significantly affected, while except Ruta the other varieties maintained lower values. At grain-filling, a moderate decrease in transpiration in response to drought was evident in Bar-Nir, Yuval and Zahir varieties as compared with the stronger response of Gedera, Galil and Ruta. The transpiration trend during recovery remained lower than the control plants, particularly in Gedera and Zahir, while it reached higher values Abstract Introduction Mediterranean winter crops are commonly and increasingly exposed to irregular rainfall and high temperatures, which lead to transient drought events of different degrees, adversely affecting growth and yield. Hence, exploring the diverse degrees of tolerance to drought existing in the crop and the molecular strategies behind it is pivotal for the development of ad hoc breeding programs. Objective We investigated the physiological and metabolic response of six commercial wheat cultivars to transient water stress at the tillering and grain-filling stages. Methods Drought experiments in lysimeters were set up at two developmental stages including six wheat cultivars. Newly expanded youngest leaves and flag leaves were Moses Kwame Aidoo and Lydia Quansah have contributed equally to the study.
IntroductionDuring the 20th century, the worldwide genetic diversity of wheat was sharply eroded ... more IntroductionDuring the 20th century, the worldwide genetic diversity of wheat was sharply eroded by continual selection for high yields and industry demands for particular standardized qualities. A collection of Israeli and Palestinian landraces (IPLR) was established to represent genetic diversity, accumulated for ten millennia under diverse environments, which was mostly lost in this transition. As our long-term goal is to study this pre- Green Revolution genetic reservoir, herein we focus on its flour and bread quality and sensorial attributes.MethodsInitially, a database was built for the entire IPLR collection (n=901) holding both Triticum durum (durum wheat) and T. aestivum (bread wheat) which included genetic and phenotypic characterization of agronomic traits, grain and flour quality. Then, a representative subset of the IPLR was selected and compared to modern varieties for dough quality, rheology, aroma and taste using both whole and refined flours and breads. The sensory ...
The rising demand for spelt wheat (Triticum aestivum ssp. spelta) as a high-value grain crop has ... more The rising demand for spelt wheat (Triticum aestivum ssp. spelta) as a high-value grain crop has raised interest in its introduction into non-traditional spelt growing areas. This study aimed to assess adaptive constrains of spelt under short Mediterranean season. At first screening of a wide spelt collection for phenology and allelic distribution at the photoperiod (PPD) and vernalization (VRN) loci was done. In addition an in-depth phenotypic evaluation of a selected panel (n = 20) was performed, including agronomically important traits and concentration of grain mineral (GMC) and grain protein (GPC) content. Results from both wide screening and in-depth in panel (group of 18 spelt lines and two bread wheat lines) evaluation shows that the major adaptive constraint for spelt under Mediterranean conditions is late heading, caused by day length sensitivity, as evident from phenology and allelic profile (PPD and VRN). All lines carrying the photoperiod-sensitive allele (PPD-D1b) were...
Journal of the Science of Food and Agriculture, 2019
BACKGROUNDFor over a century, genetic diversity of wheat worldwide was eroded by continual select... more BACKGROUNDFor over a century, genetic diversity of wheat worldwide was eroded by continual selection for high yields and industrial demands. Wheat landraces cultivated in Israel and Palestine demonstrate high genetic diversity and a potentially wide repertoire of adaptive alleles. While most Israeli‐Palestinian wheat landraces were lost in the transition to ‘Green Revolution’ semi‐dwarf varieties, some germplasm collections made at the beginning of the 20th century survived in gene banks and private collections worldwide. However, fragmentation and poor conservation place this unique genetic resource at a high risk of genetic erosion. Herein, we describe a long‐term initiative to restore, conserve, and characterize a collection of Israeli and Palestinian wheat landraces (IPLR).RESULTSWe report on (i) the IPLR construction (n = 932), (ii) the historical and agronomic context to this collection, (iii) the characterization and assessment of the IPLR's genetic diversity, and (iv) a ...
The increasing demand for spelt products requires the baking industry to develop accurate and eff... more The increasing demand for spelt products requires the baking industry to develop accurate and efficient tools to differentiate between spelt and bread wheat grains. We subjected a 272-sample spelt-bread wheat set to several potential diagnostic methods. DNA markers for γ-gliadin-D (GAG56D), γ-gliadin-B (GAG56B) and the Q-gene were used, alongside phenotypic assessment of ease-of-threshing, and Near-infrared spectroscopy (NIRS). The GAG56B and GAG56D markers demonstrated low diagnostic power in comparison to the Q-gene genotyping, which showed full accordance with the threshing phenotype, providing a highly accurate distinction between bread wheat and spelt kernels. A highly reliable Q classification was based on a three-waveband NIR model [Kappa (0.97), R-square (0.93)], which suggested that this gene influences grain characteristics. Our data ruled out a protein concentration bias of the NIRS-based diagnosis. These findings highlight the Q gene and NIRS as important, valuable, but 14 simple tools for distinguishing between bread wheat and spelt.
Uploads
Papers by David Bonfil