Sterility Characterization And Gene Mapping Of A Dominant Male Sterile Mutant OsDMS-1 In Rice

Rice is a self-pollinating crop.Male sterility is very important for genetic breeding.It not only saves the time and labour needed for artificial fertilization,but also plays a key role in the utilization of rice heterosis.Male sterility also plays an important role in the study of pollen development mechanism.Dominant male sterility(DMS)is an important male sterility.At present,few DMS materials have been found in rice.The discovery and study of new DMS materials in rice are of great significant for probing the mechanism of male sterility and breeding rice varieties.In this study,OsDMS-1 was a dominant male sterile mutant found in the tissue culture progenies of Zhonghua 11,whose fertility was not affected by temperature and light length.We observed and studied the mutational features of OsDMS-1 mutants through stereoscopic microscope,semi-thin section,scanning electron microscope and transmission electron microscope.At the same time,we used molecular markers to locate the related genes.The results are as follows:1.The effects of OsDMS-1 on agronomic traitsNo significant difference exists in agronomic traits such as tiller number and number of grains per panicle between the mutant OsDMS-1and the wild type Zhonghua 11.But the mutant plant height was slightly shorter compared to Zhonghua 11,and the mutant heading time was later than Zhonghua 11.No self-setting seeds was found,and the setting rate of hybridization was low,indicating that the mutant had a serious effecton male fertility and a certain negative effect on pistil.And its sterility is not affected by temperature and light length.2.The characteristics of OsDMS-1The mutant has no obvious difference in panicle and glumes from that of the wild type.The filament elongates normally and the anther can be normally exposed,but the anther does not dehiscence and release no pollen.The anther is slightly smaller than the wild type,the filament is thinner,most of the pollen is small and deformed,and most of the pollen grains do not accumulate starch grains,and can't be stained by iodine solution;The structure of waxy layer on the outer surface of anther wall was not significantly different from that of wild type.The degradation of tapetum began from stage 10,and the degradation was slightly delayed and incomplete than that of wild type.At the pollen maturation stage,the degeneration of the mutant anther epidermis and endodermis was also lower than that of the wild type.At the pollen maturation stage,the degeneration of the mutant anther epidermis and endodermis was lower than that of the wild type.Semi-thin section,scanning electron microscopy and transmission electron microscopy showed that the mutant was impaired in the accumulation of pollen starch grains.3.The gene mapping of mutant OsDMS-1Gene localization indicated that there were three loci controlling sterility of OsDMS-1,named OsDMS-1A(on chromosome 1),OsDMS-1B(on chromosome 2)and OsDMS-1C(on chromosome 3)respectively.OsDMS-1A was located between InDel markers C1D4 and C1D7.The genetic distance between the two markers was 0.29 cM and0.13 cM,and the physical distance between the two markers was about1.01 Mb.OsDMS-1B was located between InDel markers C2D3 and C2D10.The genetic distances between the two markers were 0.65 cM and 0.45 cM,respectively.The physical distance between the two markers was about 2.85 Mb.OsDMS-1C was located between markers C3D4 and 0315.The genetic distance between the two markers was 2.09 cM and 0.19 cM,respectively.The physical distance between the nearest markers was about 1.45 Mb.