A sorghum NAC gene is associated with variation in vascular development, biomass properties, and yield potential

Sorghum bicolor is an important cereal, forage and energy crop adapted to semiarid areas. Primary goals for crop breeding include maximizing sugar and grain yield while maintaining the rigidity and strength of the stalk. Vascular architecture influences not only stalk strength and rigidity, but also water, nutrient and sugar transport, which ultimately determine grain yield. The building blocks of the vascular system are secondary cell walls, which make up the majority of plant biomass. Understanding the gene regulatory network underlying secondary cell wall synthesis can improve the understanding of vascular development and yield and ultimately benefit future cereal breeding. This thesis describes the mapping of the Dry Midrib (D) locus in sorghum, which controls a phenotypic difference between juicy green (dd) and dry white (DD) vascular tissue. The first chapter describes fine-mapping and GWAS using green/white midrib color as the mapping phenotype. Near isogenic lines (NILs) were created, and flanking markers and genotyping-by-sequencing (GBS) were applied to BC3 and BC2F2 individuals to reduce the region of interest to a 38 kb interval containing 4 candidate genes. One of these genes is a NAC gene containing a stop codon mutation in the mutant (dd) allele. A preliminary analysis of transcriptome differences in midrib tissue of dd and DD NILs is also described. The second chapter compares differential gene expression analysis in midrib and stalk tissue of dd and DD NILs. A glycosyl hydrolase gene is differentially expressed between dd and DD NILs in midrib, stalk, and midrib + stalk analyses. Gene ontology analysis in all three sets showed significant enrichment of hydrolase activities on O-glycosal compounds and glycosal bonds in genes differentially-expressed between dd and DD. Overall, these results provide valuable hints to fine-tune sorghum breeding in the future.

Name thesis:degree_name

M.S.

Level thesis:degree_level

Thesis

Discipline thesis:degree_discipline

Crop Sciences

Grantor

University of Illinois at Urbana-Champaign

Year dc:date

2017

Author dc:creator

• Xia, Jingnu

Contributors dc:contributor

• Brown, Patrick
• Hudson, Matthew
• Moose, Stephen

• Sorghum
• NAC genes

Statement dc:rights

• Copyright 2017 Jingnu Xia

Language dc:language

en

Handle dc:identifier

http://hdl.handle.net/2142/97495

OAI identifier oai:identifier

oai:www.ideals.illinois.edu:2142/97495