Functional Analysis Of Rice OsTSD2 Gene About The Growth Of Root And Seed Development And Germination

Rice(Oryza sativa L.)is one of the most important crops in the world,especially in China.The theory of rice related growth and development has been a research hot spot.Especially after the rice as a model plant,genes related growth and development have been digging and discovering.There were some genes researching about pectin metabolism.In first,we introduced the structure,the modification,the biological function of pectin,and then extended to the researches related to the pectin methyltransferase.When our group have researched genes of rice related growth and development,we isolated a dwarf mutant,named as tsd2a(tumorous shoot development 2a).After experimental verification,the T-DNA was inserted in the seventh intron of the gene OsTSD2.Later we found the other two allelic mutants tsd2b and tsd2c.Due to the reports of homologous genes could code pectin methyltransferase in Arabidopsis thaliana,so we deduced OsTSD2 gene encoding a putative pectin methyltransferase in rice.We have analyzed the biological phenotypes of mutants shown on root growth,development and germination of seeds.Then,the main results were as follows:1.Because of methyltransferase function of OsTSD2 gene defects,we could get the main results of the mutant rice on root.For example,lower cell adhesion,the degree of methylation modification reduced,the content of endogenous hormone changes including the content of ABA increased,the content of IAA and BA reduced and gene expression of ABA signaling pathways in confusion.Then,we concluded that OsTSD2 gene regulated root length and root growth in rice.2.Knockdown of OsTSD2 disturbed the growth of rice seed.Especially,three allelic mutants about tsd2 showed lower seed setting percentage,shorter grain length,grain width narrowed and 1000-grain weight reduced.The glume of mutant tsd2 not only showed that darkened colors,aggravating the degree of rupture,but also appeared a high proportion of new backside broken.3.We could know that lower methylation pectin in scutellum of germinating mutant seeds was associating with the declining rate of mutant seed germination.The OsTSD2 gene of methyltransferase might change the degree of pectin modification to influence the seed germination of rice.In conclusion,because of methyltransferase function of OsTSD2 gene defects,it would lead to the defects of rice root growth.And it could make the seeds of rice present bad influence in the development and germination obviously.