Cloning And Analysing Of Two Dwarf Genes In Wheat

Dwarf mutants are important materials to reveal the dwarfing-related molecular mechanisms and dwarfing breeding.Two wheat dwarf mutants were analyzed and the candidate genes of dwarfing were cloned through forward genetics strategy.Both tetraploid wheat mutants Met0187 and hexaploid wheat mutants Mfh0014 showed spontaneous necrosis and dwarf phenotype in low temperature,the two different type phenotypes in F2 populations were eo-segregated.From their dwarf types and phenotypic characteristics,the mutation of GA related signaling pathway was presumed.The mutants restored the wild phenotype after spraying exogenous GA3,so,the mutations were not in the GA3 response pathway related gene.The results of quantitative expression analyzing of GA biosynthesis related genes showed that those genes have lower abundance expressions in mutants than in wild types,and the content variation of GA1 and GA20 ensured the GA biosynthesis pathway was inhibited or blocked,and resulted into dwarf phenotype.The programmed cell death phenotype was arised accompanied by dwarfing.N-acetyl-L-cysteine(NAC),a peroxide scavenger,could delay the necrotic spots formation.Antioxidant enzymes of ROS scavenging system,such as APX,GR and DHAR showed higher expression levels in mutants than in wild-type when the necrotics spots formation.It can be conferred that ROS signaling pathway leaded to excessive accumulation of peroxides,and induced the mutants produced necrotic phenotype at last.On the basis of the preliminary genetic mapping,map-based cloning of anll and anl2,two candidate genes associated with programmed cell death and dwarfing were identified.As two new members of wheat mutant library,this study provided a new perspective analysis the crosstalk mechanism of programmed cell death and dwarf phenotypes.