Investigation Into The Genetic Basis Of Increased Locule Number In Heirloom Tomato Cultivars

Abstract

Tomatoes are an important crop for many types of foods and can be easily preserved, making them an attractive candidate for selective genetic modification. One trait that could be improved upon is locule number, which can increase the practical edible mass of each tomato. To identify genes that may be responsible for this phenotype, we PCR-amplified, gel-imaged, and sequenced candidate genes in several heirloom tomato cultivars that naturally exhibit multiple locules. These candidate genes were selected from genes involved in the CLV-WUS feedback mechanism that act to control proliferation of apical meristems, which directly impact the characteristics of fruit. Absence of both a gel band in two cultivars and no DNA sequence from one of those cultivars point to mutations in SlFIN, an arabinosyltransferase involved in this feedback loop, as a possible source of this phenotype. These mutations are presumed to be large-scale deletions within this gene in two of the selected cultivars. This and future identification of natural variation will serve to focus future efforts to further confirm and describe the role that SlFIN and other genes may play in locule development during fruit growth.