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Establishing the Relationship Between Nitrogen Assimilation and Photoperiodic Injury in Tomato (Solanum lycopersicum L.)

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Title: Establishing the Relationship Between Nitrogen Assimilation and Photoperiodic Injury in Tomato (Solanum lycopersicum L.)
Author: Innes, Gregory
Department: Department of Plant Agriculture
Program: Plant Agriculture
Advisor: Micallef, BarryColasanti, JosephRaizada, Manish
Abstract: Photoperiodic injury (PI) in tomato (Solanum lycopersicum L.) is characterized by chlorosis of vegetative tissues under extended photoperiods. Analysis of a PI-resistant tomato cultivar Micro-Tom (MT) shows a relationship between PI and accumulation of toxic leaf nitrite. Nitrite is formed by nitrate reductase (NR) and converted to ammonium by nitrite reductase (NiR). We hypothesized that a decrease in the NiR:NR activity ratio predisposes plants to PI. MT maintained its normal circadian rhythms for NR and NiR activity even in 24-h light, whereas these enzyme activities became arrhythmic in a PI-susceptible line, and NiR:NR activity ratio decreased. To determine if MT can become PI-susceptible, the Micallef lab generated several transgenic Micro-Tom lines that contain a DEX-inducible antisense construct for NiR. NiR transcript levels and enzyme activity were reduced in the transgenic lines, and transgenic plants grown under an extended photoperiod exhibited PI.
URI: http://hdl.handle.net/10214/12161
Date: 2018-01


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