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Title: Investigating the genetic and molecular basis of root architecture in tomato
Author: Mansoorkhani, Fereshteh Malekpoor
ISNI:       0000 0004 6349 7421
Awarding Body: University of Nottingham
Current Institution: University of Nottingham
Date of Award: 2014
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Root system architecture (RSA) and morphology are important for plant productivity as many soil resources are unevenly distributed. RSA varies widely between species, individuals in a species and even within individual root systems. In recent years, the structure and function of plant root systems has received increasing attention. Many cultivated plants have undergone a reduction in genetic variability from ancestral forms, and this is particularly obvious in tomato whose history of domestication has significantly reduced the variation available in the cultivated tomato gene pool. However, substantial variation for root architecture and other traits still exists in related wild Solanum species. This root variability can be potentially used to breed new and improved tomato varieties. Quantitative Trait Loci (QTL) for root architecture and other important traits can be identified using available sets of tomato introgression lines, which were developed through a succession of backcrosses. The small green-fruited species Solanum pennellii is a distant sexually compatible relative of S. lycopersicum (domesticated tomato) native to the Andes mountains of South America. S. pennelli was used as a founding donor parent of the first tomato introgression (IL) population made available for interspecific QTL identification, cloning, and plant breeding. In this project, the S. pennellii IL population was used as the starting point to fine map QTL involved in the control of tomato root architecture. A large effect QTL was identified on the top of tomato chromosome 4. The QTL region enhanced root length and number of lateral roots. To fine map the underlying gene(s), approximately 8000 IL 4-1-1 F2 plants were screened to identify recombinants, leading to the generation of two small ILs (Q1120 and Q2173) harbouring the root system architecture (RSA) QTL. These recombinants delineated a mapping interval of 177kb containing 26 gene models. Analysis of the genes in the mapping interval indicated that several showed expression depending on the presence of an M82 or S.pennellii allele. Based on these and other criteria two genes were selected as RSA QTL candidates. These included a transcription factor belonging to the bHLH class and the gibberellin receptor GID1. Functional studies in Arabidopsis and tomato are in progress to validate the link between these genes and improved RSA.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available