The Research On Relevant Genes Of Male Gametophytic Mutant Ovp1in Arabidopsis Thaliana

Pollen development is a complex and exactly controlled biological process that involves a series of vital events that require cooperative interactions between sporophytic and gametophytic genes.A genetic screening was established based on segregation ratio distortion of Ds transposon-borne containing a kanamycin resistance marker and one mutant over vacuolated pollen (ovpl) was isolated eventually, which transmission efficiency reduced predominantly through the male gametophytes, and was not affected through the female.The microspores arrested in ovpl increased dramatically from late binucleate stage to early trinucleate stage, eventually resulting in completely male gametophytic lethal phenotypes. No homozygous individuals were identified until now, and progeny from heterozygous of ovpl exhibited a stable1:1segregation ratio under selection. Consistent with this, cytologic and morphologic analysis of pollen from wild-type and ovpl mutants demonstrated the mutation had no obviously effect on the outer (exine), but over vacuolated pollen grains appeared at the pollen mitosis II stage.Subsequently, Inverse-PCR amplification the3’end of Ds flanking sequence identified a Ds insertion in the1st exon of At2g01560, which encodes a protein of unknown function. Moreover, Tail-PCR isolated the5’end of Ds insertion which located between At2g01910and At2g01913. Allelic analysis and molecular complementation by introducing the full-length of At2g01560and At2g01913manifested that none of them were responsible for the abortion phenotype in ovpl.Molecular and genetic analysis of the insertion sites revealed the Ds element resulted in genomic deletion between Al2g01910and At2g01913. The deleted region was predicted to encode40genes embracing one or more potential genes with important function(s) during pollen maturation.In addition, a male sterile mutant with abnormal microspores’exine and tapetum is described here. The ms360fertility defects resulted from a recessive mutation in a single genetic locus. The mutation was genetically mapped to chromosome III and located closely to the molecular marker nga162and nga172. In light of bioinformatics knowledge, the defects of ms360may be caused by the loss function of DEX1, this speculation was confirmed by sequencing of mutant alleles. DEX1encodes a novel plant protein that is predicted to be membrane associated and consists of several potential calcium-binding domains. Pollen wall development of dexl parallels that of wild-type plants until the early tetrad stage. In dexl plants, primexine deposition is delayed and significantly reduced.