Epsilon Archive for Student Projects

Abstract

To reproduce, plants either require a mate to pollinate their flowers (outcrossing) or pollinate themselves (selfing). However, pollination in plants tends to require a pollinator. Selfing plants, though, as a direct consequence of being selfers, do not invest as many resources into attracting pollinators. They reallocate resources into different parts. This reallocation can be seen in the morphological changes known as the ‘selfing syndrome’. It is well known that a prominent selfing syndrome trait is producing less nectar. This project used Capsella grandiflora, Capsella rubella and Capsella orientalis to characterize changes in nectar secretion, nectar composition, nectaries and to analyse RNAseq data from these plants’ flowers to produce a nectar-specific candidate gene in the context of the selfing syndrome and confirm that this candidate gene influences nectar secretion.
We confirmed that the selfer Capsella species produce less nectar. We found that selfer lineages produced less nectar with higher sugar concentrations. Capsella nectar was also shown to have both species and mating-mode specific compositional changes. We also found that nectary structures do not undergo the same disruptions in both Capsella selfer lineages.
We uncovered a novel candidate gene for the Capsella nectar secretion differences: CANDIDATE1. This transporter gene was then partially confirmed to affect nectar secretion through the use of C. grandiflora x C. rubella NILs. We attempted to fully confirm our finding by knocking this gene out in C. grandiflora with CRISPR/Ca9, but we were unsuccessful in doing so.