Quantitative Changes in the Transcription of Phytohormone-Related Genes: Some Transcription Factors Are Major Causes of the Wheat Mutant dmc Not Tillering.

Ruishi He,Qiaoyun Li,Xinxin Zhu,Yumei Jiang,Jishan Niu,Zhixin Jiao,Yongjing Ni,Junchang Li

doi:10.3390/ijms19051324

Abstract

Tiller number is an important agronomic trait for grain yield of wheat (Triticum aestivum L.). A dwarf-monoculm wheat mutant (dmc) was obtained from cultivar Guomai 301 (wild type, WT). Here, we explored the molecular basis for the restrained tiller development of the mutant dmc. Two bulked samples of the mutant dmc (T1, T2 and T3) and WT (T4, T5 and T6) with three biological replicates were comparatively analyzed at the transcriptional level by bulked RNA sequencing (RNA-Seq). In total, 68.8 Gb data and 463 million reads were generated, 80% of which were mapped to the wheat reference genome of Chinese Spring. A total of 4904 differentially expressed genes (DEGs) were identified between the mutant dmc and WT. DEGs and their related major biological functions were characterized based on GO (Gene Ontology) and KEGG (Kyoto Encyclopedia of Genes and Genomes) categories. These results were confirmed by quantitatively analyzing the expression profiles of twelve selected DEGs via real-time qRT-PCR. The down-regulated gene expressions related to phytohormone syntheses of auxin, zeatin, cytokinin and some transcription factor (TF) families of TALE, and WOX might be the major causes of the mutant dmc, not tillering. Our work provides a foundation for subsequent tiller development research in the future.

Highlights

Wheat (Triticum aestivum L.) is one of the most important food crops in the world
Sixty-nine percent of significant differentially expressed genes (DEGs) (FC ≥ 2) were highly expressed and 31% were expressed at a low level in dmc
The majority of genes that were expressed at a low level belonged to the classes of DNA replication, transcription, and translation, as well as zeatin synthesis

Summary

Introduction

Since tiller number is an important agronomic trait for grain yield [1,2], it has always been one of the key traits to select in breeding programs. Low and high tillering wheat mutants do not have very high grain yield. Tiller number as well as grain number and weight affect yield. Four tiller inhibition lines or mutants have been reported in wheat. In barley (Hordeum vulgare), the tiller inhibition genes lnt, als, cul, int-b and uzu have been reported, and they have been mapped on Chr. 3HL [7], 3HL [8], 3HL [9], 5HL [9] and 3 HL [9], respectively. Many tiller related mutants have been reported in rice (Oryza sativa) [10,11,12]

Methods

Results

Discussion

Conclusion