The Quantitative Genetic Control of Root Architecture in Maize.

Adam L Bray,Christopher N Topp

doi:10.1093/pcp/pcy141

Adam L Bray, Christopher N Topp

Open Access

https://doi.org/10.1093/pcp/pcy141

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Abstract

Roots remain an underexplored frontier in plant genetics despite their well-known influence on plant development, agricultural performance and competition in the wild. Visualizing and measuring root structures and their growth is vastly more difficult than characterizing aboveground parts of the plant and is often simply avoided. The majority of research on maize root systems has focused on their anatomy, physiology, development and soil interaction, but much less is known about the genetics that control quantitative traits. In maize, seven root development genes have been cloned using mutagenesis, but no genes underlying the many root-related quantitative trait loci (QTLs) have been identified. In this review, we discuss whether the maize mutants known to control root development may also influence quantitative aspects of root architecture, including the extent to which they overlap with the most recent maize root trait QTLs. We highlight specific challenges and anticipate the impacts that emerging technologies, especially computational approaches, may have toward the identification of genes controlling root quantitative traits.

Highlights

Plant physiologists have spent many years thoughtfully characterizing roots in fine detail, and creating an intricate vocabulary to describe their observations
Common terminologies have been proposed at various times by the International Society of Root Research (ISRR), the Plant Ontology Consortium and maize researchers (Feix et al 2002, Ilic et al 2007, Hochholdinger 2009, Zobel and Waisel 2010)
Root traits have generally been grouped based on developmental criteria, anatomy and topology

Summary

Introduction

Plant physiologists have spent many years thoughtfully characterizing roots in fine detail, and creating an intricate vocabulary to describe their observations. Topp | The quantitative genetic control of root architecture in maize in different environments by concerted ‘fine-tuning’ of many loci (Gifford et al 2013, Rosas et al 2013) This idea has not been well tested in crop plants, largely because few genes have been identified that control root architecture. No mutants have been identified for Rul but, interestingly, the rtcl mutant has a less severe phenotype than rtcs, resulting in normal seminal roots and reduced length of crown roots This observation supports the finding from Schnable and Freeling (2011) that genes from the maize subgenome are over-represented in the historic identification of visible mutant phenotypes because of their increased severity. AGeneID is from B73 v3 reference. bThese genes were identified by homology to rum and AtLRP1, and are predicted to have similar phenotypes but no mutants exist to validate these phenotypes

8.06 Zhang et al (2015)

66 Landrace F1 DH

Findings

Conclusions and Outlooks