Morphology, Heredity And Differentially Expressed Gene Analysis Of A Wheat Mutant Dms

Two key elements determining wheat(Triticum aestivum L.)yield are plant height and spike,whose mutants are ideal materials for studies on molecular mechanisms of stem and floral organ development.It is advantageous for understanding the developmental mechanism of stem and spike,and more to explore new ways for wheat breeding,to study mutants for these traits.With a wheat mutant dms,conferring to dwarfing status,multi-pistil and sterility,morphology,primary heredity and transcriptome sequencing analysis were carried out in the study.The results are as follows:1.Simple sequence repeat(SSR)marker assay with 181 primer pairs showed that only one locus of GWM148-2B was different between ?Zhoumai 18? and dms,which indicated that the dms was derived from “Zhoumai 18”.2.There were three typical phenotypes in the progeny of dms: tall(T;ca.0.8 m),semi-dwarf(M;ca.0.6 m)and dwarf(D;under 0.3 m)plants.Morphological investigation indicated that the internode length of M was shortened by about 20-50 mm each comparing with T and ?Zhoumai 18?;the internode number of D was three which was two less than that of T and ?Zhoumai 18?,and its internode length was shorter,too.The D plant was sterile,with plant height no more than 30 cm and with muti-pistils.3.Segregated phenotypes in progeny of M suggested that the multi-pistils and sterility were controlled by one recessive gene locus that designated as Tadms,and the plant height was controlled by a gene locus Ta DMS.Therefore,individuals of the dms had three genotypes,Ta DMSTa DMS for tall plants,Ta DMSTadms for semi-dwarf plants and Tadms Tadms for dwarf plants.4.Four Unigenes libraries were assembled by sequencing the m RNA super-bucks of differentiating spikes and stem tips of D and T.with comprehensive integrative analysis,419 genes specifically expressed in spikes were identified.Nine out of them were typical homeotic genes of MADS-box family,AP2,FL and DL genes.The biological processes of purine and pyrimidine metabolism,DNA replication,transcription and translation were more active in differentiating spikes.5.Analysis of genes differential expression showed that 143 genes were significantly regulated by Tadms in differentiating spikes,and 26 genes out of them were putatively involved in spike specification.Spatio-temporal expression profiles of twelve important genes were investigated by QRT-PCR.The results showed that Tadms inhibited the expression of Ta AP1-2 and Ta AP2,significantly.Genes involved in most biological processes were also regulated by Tadms,including transcription,translation,cell division,photosynthesis,carbohydrate transport and metabolism,energy production and conversion,and response to out stimulus.Especially,the genes in pathways of photosynthesis and carbohydrate metabolism were suppressed.According to the results above,we got the conclusions that the major causal factors accounting for spike abnormalities of dms were inhibited expression of homeotic genes,hormonal imbalance,repressed biological processes,and deficiency of construction materials and energy.