Abstract Detail

Characteristics of nectar, nectaries, and nectar spurs

Liao, Irene [1], Rausher, Mark [1].

Differentially expressed genes contributing to the evolution of reduced nectar in the selfing syndrome.

Nectar production is one of the floral traits reduced in the selfing syndrome, a composite of traits that have changed in association with the shift from outcrossing to self-pollination. However, the evolutionary and genetic processes leading to reduced nectar traits – nectar volume and nectar sugar concentration – is poorly understood. One study demonstrates that selection has contributed to the divergence in nectar traits between a pair of morning glory species, the outcrossing Ipomoea cordatotriloba and the selfing I. lacunosa (Convolvulaceae). However, as a polygenic trait, it is unclear whether one or a few of these genes could lead to major changes in nectar production between these species. Although molecular characterizations of a handful of nectar and nectary genes in Arabidopsis and Nicotiana have yielded candidates for studies across other non-model organisms, these genes fail to present a comprehensive picture of the process of producing nectar. As an attempt to identify genes responsible for reduced nectar in the selfing morning glory, Ipomoea lacunosa, we are taking a comparative genetics approach, combining bulk-segregant analysis, RNA sequencing, and QTL mapping. Using 100 recombinant inbred lines from a cross between I. cordatotriloba and I. lacunosa, we measured nectar volume and nectar sugar concentration, identified individuals with the 30 highest and lowest values for both traits, extracted and pooled the nectaries from each extreme, and sequenced the RNA. We found thousands of genes differentially expressed between the two extreme pools, some of which include known nectar and nectary genes CRC, SW9, MYB305. We then asked which of these genes are found within the nectar QTLs identified from a previous experiment and whether any of these genes may display molecular signatures of selection. This presents an opportunity to identify novel nectar candidates, especially those contributing to the evolution of reduced nectar in the selfing syndrome.

1 - Duke University, Department of Biology, 130 Science Drive, Durham, NC, 27708, USA

Keywords:
nectar
selfing syndrome
differential expression
morning glories.

Presentation Type: Colloquium Presentations
Session: COL02, Characteristics of nectar, nectaries and nectar spurs
Location: Virtual/Virtual
Date: Monday, July 27th, 2020
Time: 10:45 AM
Number: COL02004
Abstract ID:392
Candidate for Awards:None