Genetic Mapping And Functional Analyses Of Arabidopsis Male Sterile Mutant Ms1142

ms1142 is a male sterile mutant which is isolated from a population of wild type Arabidopsis thaliana treated with EMS. Compared with the wild-type, ms1142 mutant plants have small siliques with no seed set. Genetic analysis indicated that it is controlled by a single recessive nuclear gene. Map-based cloning technique was used and the mutant gene MS1142 was mapped to a region of 44-kb in BAC clone F16P17 on chromosome 1. Based on bioinformatics analysis and sequencing, we found that there was a base changed from T to C in gene AT1G62940, which resultd in a proline replacement by a leucine in the encoded protein MS 1142. Genetic complementation and allelism analysis experiment results showed that mutation of AT1g62940 gene led to the male sterile phenotype. Cytological observation indicated that during anther development, the microspores are ruptured and no pollen grains are formed in the mutant anther locules. Further examination by scanning electron microscopy indicated that the mutant microspore exine was aberrant and broken. Moreover, transmission electron microscopy analysis showed that sporopollenin deposition was abnormal and the mutant pollen exine was irregular. Real-time PCR, double mutant analysis and in situ hybridization experiment data suggested that MS1142 acts indirectly downstream of AMS. All these results indicate that MS1142 gene plays important roles in pollen development and exine pattern formation.