A gene regulatory network model for floral transition of the shoot apex in maize and its dynamic modeling.

Zhanshan Dong,Olga Danilevskaya,Mark Cooper,Nathan Coles,Carlos Messina,Tabare Abadie,Frank G Harmon

doi:10.1371/journal.pone.0043450

Abstract

The transition from the vegetative to reproductive development is a critical event in the plant life cycle. The accurate prediction of flowering time in elite germplasm is important for decisions in maize breeding programs and best agronomic practices. The understanding of the genetic control of flowering time in maize has significantly advanced in the past decade. Through comparative genomics, mutant analysis, genetic analysis and QTL cloning, and transgenic approaches, more than 30 flowering time candidate genes in maize have been revealed and the relationships among these genes have been partially uncovered. Based on the knowledge of the flowering time candidate genes, a conceptual gene regulatory network model for the genetic control of flowering time in maize is proposed. To demonstrate the potential of the proposed gene regulatory network model, a first attempt was made to develop a dynamic gene network model to predict flowering time of maize genotypes varying for specific genes. The dynamic gene network model is composed of four genes and was built on the basis of gene expression dynamics of the two late flowering id1 and dlf1 mutants, the early flowering landrace Gaspe Flint and the temperate inbred B73. The model was evaluated against the phenotypic data of the id1 dlf1 double mutant and the ZMM4 overexpressed transgenic lines. The model provides a working example that leverages knowledge from model organisms for the utilization of maize genomic information to predict a whole plant trait phenotype, flowering time, of maize genotypes.

Highlights

Flowering time is a major adaptive trait in plants and an important selection criterion in plant breeding [1]
Major components of the genetic control system for the flowering time in Arabidopsis thaliana have been defined in the past decades
The purpose of this paper is to develop a simple model that will serve as a foundation for Dynamic Gene Network (DGN) modeling of the vegetative to reproductive transition in maize

Summary

Introduction

Flowering time is a major adaptive trait in plants and an important selection criterion in plant breeding [1]. Heat units or growing degree days to shedding and to silking are examples of empirical models widely used to synchronize shedding and silking events in seed production [22,23,24] When these models were embedded within comprehensive physiological frameworks such as CERES [25] and APSIM [26] they were applied to understand the physiological basis of maize adaptation in different environment types, construct trait performance landscapes, and predict responses to trait selection in breeding programs [27]. Empirical models such as the heat unit model have limitations to predict flowering time for novel genotypes. The DGN model is evaluated against field experimental data for flowering time of novel genotypes created from allelic variation for specific genes and from expression of transgenes

Materials and Methods

Conclusions