Physiological Characteristics Investigation And Genetic Mapping Of Tomato Yellow Leaf Gene NV

Tomato（Solanum lycopersicum） is a very important vegetable crop belonging to tomato genus of Solanaceae family. Leaf-color mutation can be used as seedling markers for rapid purity identification of variety and some mutants have excellent traits which can be used for breeding. Leaf-color mutant is not only the ideal material to study the chloroplast structure, chlorophyll metabolism, photosynthesis characteristics, but also can be used for exploring regulation of gene expression. Therefore, it is important to make good study of tomato leaf-color mutation, which could provide theoretical and practical basis for for the mutant gene function and genetic breeding are important.Tomato yellow leaf mutant Manapal contains stably inherited yellow leaf gene nv（netted virescent）. In this study we used advanced backcross population of Manapal and Solanum pennellii LA0716 for research of photosynthetic pigment content, chloroplasts structure and photosynthetic parameters of nv plant. Molecular markers and genome resequencing anlysis were used for nv genetic analysis, aimed at exploring the physiological mechanisms and fine mapping of nv. The main findings are as follows:1. We built BC₇S₁, BC₇S₂ and BC₈ near isogenic lines.2. Chlorophyll a, chlorophyll b content, total chlorophyll content of nv plant was significantly lower than green-leaf plants, and carotenoids reduce less. There were no significant differences between nv plants and green-leaf plants about ratio of chlorophyll a and chlorophyll b.Chloroplasts of nv plants were not as green as green-leaf plants, most chloroplasts were irregularly shaped, thylakoid dysplasia. There were little grana and stroma, and stacked pile were irregular.The net photosynthetic rate of nv plant（Pn） were lower than the green-leaf plants, stomatal conductance（G2） and intercellular CO2 concentration（Ci）were higher than green-leaf plants.3.21 molecular markers located on tomato chromosome 9 were used to make genetic analysis of more than 2000 plants from near isogenic line. Finally, nv was mapped between two markers InD-09-4-1 mark and HP63/64 on chromosome 9.4. Using genome resequencing analysis technology, selected 12 candidate genes.