Abstract
Several genes positively influence final leaf size in Arabidopsis when mutated or overexpressed. The connections between these growth regulators are still poorly understood although such knowledge would further contribute to understand the processes driving leaf growth. In this study, we performed a combinatorial screen with 13 transgenic Arabidopsis lines with an increased leaf size. We found that from 61 analyzed combinations, 39% showed an additional increase in leaf size and most resulted from a positive epistasis on growth. Similar to what is found in other organisms in which such an epistasis assay was performed, only few genes were highly connected in synergistic combinations as we observed a positive epistasis in the majority of the combinations with samba, BRI1(OE) or SAUR19(OE). Furthermore, positive epistasis was found with combinations of genes with a similar mode of action, but also with genes which affect distinct processes, such as cell proliferation and cell expansion.DOI: http://dx.doi.org/10.7554/eLife.02252.001.
Highlights
Since Bateson introduced the term epistasis to describe the phenomenon that some mutations seemed to be ‘stopping’ or ‘standing above’ the effect of other mutations (Bateson, 1909), it became clear that interactions between multiple genes influence many traits
In plants overexpressing EXPANSIN 10 (EXP10) and SMALL AUXIN UP-REGULATED RNA 19 (SAUR19) fused to a GFP tag, bigger leaves containing larger cells are produced (Cho and Cosgrove, 2000; Spartz et al, 2012). Several of these leaf growth-promoting genes are involved in hormonal pathways, confirming the importance of plant hormones in the regulation of growth processes: BRASSINOSTEROID INSENSITIVE 1 (BRI1) encodes a brassinosteroid receptor, GA20OX1 catalyzes rate-limiting steps in late gibberellic acid (GA) biosynthesis, ANT has been suggested to be involved in auxin signal transduction and both AVP1 and SAUR19 in auxin transport (Huang et al, 1998; Mizukami and Fischer, 2000; Wang et al, 2001; Li et al, 2005; Spartz et al, 2012)
In order to identify potential interactions existing within the genetic network regulating leaf growth, we pairwised combined 13 gene perturbations each leading to an enhanced leaf size and looked for positive interactions resulting in an increased leaf area larger than the additive combination of the single perturbations
Summary
Since Bateson introduced the term epistasis to describe the phenomenon that some mutations seemed to be ‘stopping’ or ‘standing above’ the effect of other mutations (Bateson, 1909), it became clear that interactions between multiple genes influence many traits. Numerous studies on the effect of pairwise gene perturbations have been conducted, primarily in the budding yeast Saccharomyces cerevisiae, to systematically evaluate epistasis for several characteristics, such as fitness or synthetic lethality (Tong et al, 2004; Jasnos and Korona, 2007; St Onge et al, 2007; Dixon et al, 2009; Costanzo et al, 2010, 2011) These genome-scale genetic interactions studies were facilitated by the availability of large collections of deletion strains and the development of automated platforms to analyze the phenotypes of double mutants (Scherens and Goffeau, 2004).
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
