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Lateral root development in response to mineral nutrients; signal mechanisms and pathways.
Halamková, Daniela ; Tylová, Edita (advisor) ; Lhotáková, Zuzana (referee)
TTL3 gene was identified by forward screening of genes involved in lateral root development in Arabidopsis thaliana based on its expression pattern. TTL3 belongs to the TTL (TETRATRICOPEPTIDE-REPEAT THIOREDOXIN-LIKE) gene family. The diploma thesis is aimed on characterisation of changes in TTL1, TTL3 a TTL4 promotor activities in response to external conditions (availability of nitrogen or phosphorus) that affect root growth. Obtained data should elucidate possible relation among TTL gene expression activities, root growth rate, and apical meristem activity. Nitrogen or phosphorus deficiency triggered changes in root growth and root system morphology of experimental plants. Short-term nitrogen deficiency stimulated root growth. Short-term phosphorus deficiency induced gradual growth cessation in main root and long laterals. Long-term deficiency reduced root growth of both N-deficient and P-deficient plants compared to control. The root system size of N-deficient and P-deficient plant was almost similar. Determination of promotor activity using β-glucuronidase reporter gene showed changes in expression activity and its localization in response to root growth intensity. TTL4 gene promotor activity was the most responsive. Its activity was generally higher in slowly growing roots, particularly under...
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Control of lateral root development in response to availability of principal mineral nutrients.
Halamková, Daniela ; Tylová, Edita (advisor) ; Smetana, Ondřej (referee)
Lateral roots are, due to their large absorption surface, a part of the root system with significant importance for the plant's ingestion of water and nutrients. Their development depends on heterogeneity of soil environment, which enables the plant to optimize the acquisition of resources under current conditions. The availability of mineral nutrients (type of nutrient, form, distribution in soil and mobility) is one of key factors that determine root system morphogenesis. Another important aspect is the amount of nutrient in the plant; in other words, the plant's current demand for the element. The most important nutrients that influence the architecture of the root system are two macroelements - nitrogen and phosphorus. Both of these elements trigger positive and negative effects on the development of lateral roots. Nitrate, important source of nitrogen, induces two entirely different regulatory mechanisms of lateral root development. Under nitrogen limiting condition, a local stimulation of lateral root elongation is triggered in nitrate-rich patches. This response integrates the signalling pathways of auxin and nitrate. In contrast, high and homogenous availability of nitrate in rhizosphere (≥ 10 mM) causes inhibition of lateral root growth. This systemic inhibitory effect was similarly...
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Lateral root development in response to mineral nutrients; signal mechanisms and pathways.
Halamková, Daniela ; Tylová, Edita (advisor) ; Lhotáková, Zuzana (referee)
TTL3 gene was identified by forward screening of genes involved in lateral root development in Arabidopsis thaliana based on its expression pattern. TTL3 belongs to the TTL (TETRATRICOPEPTIDE-REPEAT THIOREDOXIN-LIKE) gene family. The diploma thesis is aimed on characterisation of changes in TTL1, TTL3 a TTL4 promotor activities in response to external conditions (availability of nitrogen or phosphorus) that affect root growth. Obtained data should elucidate possible relation among TTL gene expression activities, root growth rate, and apical meristem activity. Nitrogen or phosphorus deficiency triggered changes in root growth and root system morphology of experimental plants. Short-term nitrogen deficiency stimulated root growth. Short-term phosphorus deficiency induced gradual growth cessation in main root and long laterals. Long-term deficiency reduced root growth of both N-deficient and P-deficient plants compared to control. The root system size of N-deficient and P-deficient plant was almost similar. Determination of promotor activity using β-glucuronidase reporter gene showed changes in expression activity and its localization in response to root growth intensity. TTL4 gene promotor activity was the most responsive. Its activity was generally higher in slowly growing roots, particularly under...
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Control of lateral root development in response to availability of principal mineral nutrients.
Halamková, Daniela ; Tylová, Edita (advisor) ; Smetana, Ondřej (referee)
Lateral roots are, due to their large absorption surface, a part of the root system with significant importance for the plant's ingestion of water and nutrients. Their development depends on heterogeneity of soil environment, which enables the plant to optimize the acquisition of resources under current conditions. The availability of mineral nutrients (type of nutrient, form, distribution in soil and mobility) is one of key factors that determine root system morphogenesis. Another important aspect is the amount of nutrient in the plant; in other words, the plant's current demand for the element. The most important nutrients that influence the architecture of the root system are two macroelements - nitrogen and phosphorus. Both of these elements trigger positive and negative effects on the development of lateral roots. Nitrate, important source of nitrogen, induces two entirely different regulatory mechanisms of lateral root development. Under nitrogen limiting condition, a local stimulation of lateral root elongation is triggered in nitrate-rich patches. This response integrates the signalling pathways of auxin and nitrate. In contrast, high and homogenous availability of nitrate in rhizosphere (≥ 10 mM) causes inhibition of lateral root growth. This systemic inhibitory effect was similarly...
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