Genetic insights into the modification of the pre-fertilization mechanisms during plant domestication

Abstract

Plant domestication is the process of adapting plants to human use by selecting specific traits. The selection process often involves the modification of some components of the plant reproductive mechanisms. Allelic variants of genes associated with flowering time, vernalization, and the circadian clock are responsible for the adaptation of crops, such as rice, maize, barley, wheat, and tomato, to non-native latitudes. Modifications in the plant architecture and branching have been selected for higher yields and easier harvests. These phenotypes are often produced by alterations in the regulation of the transition of shoot apical meristems to inflorescences, and then to floral meristems. Floral homeotic mutants are responsible for popular double-flower phenotypes in Japanese cherries, roses, camellias, and lilies. The rise of peloric flowers in ornamentals such as snapdragon and florists’ gloxinia is associated with non-functional alleles that control the relative expansion of lateral and ventral petals. Mechanisms to force outcrossing such as self-incompatibility have been removed in some tree crops cultivars such as almonds and peaches. In this review, we revisit some of these important concepts from the plant domestication perspective, focusing on four topics related to the pre-fertilization mechanisms: flowering time, inflorescence architecture, flower development, and pre-fertilization self-incompatibility mechanisms.

Understanding Past, and Predicting Future, Niche Transitions based on Grass Flowering Time Variation

“…Another trend is that all taxa appear to have both repressors and promoters of flowering that are active under both long and short days. This suggests that photoperiod has been an important cue for flowering throughout the lifespan and range of the grass family, as is observed at the cultivar level in most cereal crops (Liu et al, 2015;Manrique et al, 2019).…”

Paternity tests support a diallelic self‐incompatibility system in a wild olive (Olea europaea subsp. laperrinei, Oleaceae)

“…We however did not use stigma tests to investigate the behavior of the self-pollen on these three cultivars, preventing us to conclude on the reason of self-crosses (i.e., self-compatibility mutation vs. leaky self-incompatibility). Selfing in cultivated olives could indeed result from the artificial selection of self-compatible mutants over millennia, particularly via their vegetative propagation (Manrique et al, 2019;McKey, Elias, Pujol, & Duputié, 2010;Rowlands, 1964). Recurrent admixture events between divergent olive gene pools (East vs. West;Besnard, Terral, & Cornille, 2018) may also result in a huge phenological variation in the mating system of the cultivated olive, and more frequent selfing is expected in admixed individuals (as shown for instance in hybrids of ash trees and beets; Arnaud, Fénart, Cordellier, & Cuguen, 2010;Gérard, Klein, Austerlitz, Fernández-Manjarrés, & Frascaria-Lacoste, 2006).…”

Advances in plant reproduction: from gametes to seeds

“…Every crop that we know today has already been radically modified from how it originally appeared in the wild. In this issue Manrique et al (2019) describe the remarkable domestication processes that have led to alterations in the reproductive mechanisms of plants. Studies have revealed how domestication has affected many species at the genetic and molecular levels, demonstrating that humans have long been influencing the genetic modification of plants.…”