Genetic and Molecular Control of Floral Organ Identity in Cereals

Abstract

Grasses represent a major family of monocots comprising mostly cereals. When compared to their eudicot counterparts, cereals show a remarkable morphological diversity. Understanding the molecular basis of floral organ identity and inflorescence development is crucial to gain insight into the grain development for yield improvement purposes in cereals, however, the exact genetic mechanism of floral organogenesis remains elusive due to their complex inflorescence architecture. Extensive molecular analyses of Arabidopsis and other plant genera and species have established the ABCDE floral organ identity model. According to this model, hierarchical combinatorial activities of A, B, C, D, and E classes of homeotic genes regulate the identity of different floral organs with partial conservation and partial diversification between eudicots and cereals. Here, we review the developmental role of A, B, C, D, and E gene classes and explore the recent advances in understanding the floral development and subsequent organ specification in major cereals with reference to model plants. Furthermore, we discuss the evolutionary relationships among known floral organ identity genes. This comparative overview of floral developmental genes and associated regulatory factors, within and between species, will provide a thorough understanding of underlying complex genetic and molecular control of flower development and floral organ identity, which can be helpful to devise innovative strategies for grain yield improvement in cereals.

Integrated Analysis of Small RNA, Transcriptome and Degradome Sequencing Provides New Insights into Floral Development and Abscission in Yellow Lupine (Lupinus luteus L.)

“…This is especially true for crop plants, as it is directly tied to potential yield. Molecular basis for flower formation has been extensively studied for many years across different plant species, and described collectively by ABCDE model (reviewed in [5]), with slight modifications depending on either species or flower shape [6]. Mutations that occur in genes governing flower formation cause various morphogenetic aberrations, including changes in the identity, number, and positioning of floral organs [7].…”

Isolation and Functional Analysis of a PISTILLATA-like MADS-Box Gene from Argan Tree (Argania spinosa)

“…MADS-box proteins interact in a combinatorial fashion to specify the identity of a particular floral organ. Thirty years ago, the ABC model was proposed and established three homeotic gene classes: A, B, and C [ 18 ]. Class A genes alone produce sepals, and in combination with B-class genes, regulate petal identity.…”

Cloning of Long Sterile Lemma (lsl2), A Single Recessive Gene Regulating Spike Germination in Rice (Oryza Sativa L.)

“…In eudicots, owers are generally composed, from outer whorls to inner whorls, of sepals (whorls), petals (whorls), stamens (whorls), and pistils (whorls). Based on molecular and genetic analyses in several eudicot species, including Arabidopsis thaliana, snapdragon (Antirrhinum majus), and petunia (Petunia hybrida), an ABC model has been proposed that determines the characteristics of each organ and control oral meristem determinacy by combining A/B/C/D gene groups [2][3][4][5][6][7]. According to the model, three homologous genes control the formation of ower organs.…”