Morphology And Transcriptome Analysis Of A Wheat Mutant Dmc

Wheat(Triticum aestivum L.)is one of most important food crops in the world.Tiller number is an important agronomic trait for grain yield in Wheat,whose mutants are ideal materials for studies on molecular mechanisms of Tiller development.It is advantageous for understanding the developmental mechanism and regulatory pathway of Tiller,to explore more new ways for wheat breeding.In this study,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.The results are as follows:1.Typically,the mutant dmc only had a main stem.The average plant height of dmc was 48.00 cm,the average spike length was 6.48 cm.The leaf color of dmc was yellow green at seedling stage,but it became normal green after jointing stage.The number of spikelets on the main spike,the number of grains per spike,and 1000-grain weight of dmc were significantly less than those of Guomai 301.The heading,florescence and maturation times of dmc were significantly later than that of Guomai 301 with about a week.Histological observation indicated that the cell size of dmc was smaller than that of Guomai 301.2.Total 431 wheat SSR markers were used to evaluate the genetic diversity between dmc and Guomai 301.There was no polymorphic SSR locus between dmc and Guomai 301 had been found,which demonstrated that their genetic backgrounds were highly consistent,and the dmc was derived from Guomai 301 indeed.The average tiller numbers of dmc and Chinese Spring was 1.10 and 34.00,respectively.The average tiller number of the F1 generation derived from cross dmc / Chinese Spring was 4.48.These data suggested that the monoculm trait probably was controlled by dominant or semidominant gene / genes.3.Two bulked samples of mutant dmc(T1,T2 and T3)and WT(T4,T5 and T6)with three biological replicates were comparatively analyzed at 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.4.Total 4,904 differentially expressed genes(DEGs)were identified between mutant dmc and WT.DEGs and their related major biological functions were characterized based on GO and KEGG categories.These results were confirmed by quantitative analyzing the expression profiles of twelve selected DEGs via real-time q RT-PCR.The down-regulated gene expressions related to phytohormone syntheses of auxin,zeatin,cytokinin and some TF families of TALE,and WOX might were the major causes of mutant dmc not tillering.