Identification of Candidate Genes Responsible for Stem Pith Production Using Expression Analysis in Solid-Stemmed...

Area of Science:

• Plant genetics
• Agricultural entomology
• Molecular biology

Background:

• The wheat stem sawfly (WSS) poses a significant economic threat to wheat production in the Northern Great Plains.
• Wheat stem solidness, controlled by a major quantitative trait locus (QTL), is the primary resistance mechanism against WSS.

Purpose of the Study:

• To identify candidate genes responsible for stem solidness in wheat using RNA sequencing (RNA-seq).
• To pinpoint genes within a specific genomic region linked to the stem solidness QTL.

Main Methods:

• RNA sequencing (RNA-seq) was employed to analyze gene expression in solid and hollow-stemmed wheat near-isogenic lines (NILs).
• Single nucleotide polymorphism (SNP) markers derived from expressed sequence tags (ESTs) were used to genotype and map genes within the QTL region.
• Allele-specific expression analysis was performed on EST markers in wheat stem tissues.

Main Results:

• Four annotated genes corresponding to EST markers showed differential expression between solid and hollow-stemmed NILs, indicating potential roles in stem solidness.
• Out of 260 annotated genes within the 5.13 cM QTL region, 20 were upregulated in hollow stems and seven in solid stems.
• A specific S-methyltransferase gene was identified as a strong candidate due to differential expression and putative function.

Conclusions:

• The study identified several candidate genes associated with wheat stem solidness, providing targets for future research.
• Understanding these genes can enhance marker-assisted selection for WSS resistance in wheat breeding programs.
• Further investigation into these candidate genes may lead to improved strategies for managing wheat stem sawfly (WSS).