Effect Of OsRab7 On Pollen Development And Salt Resistance In Rice

Rice(Oryza sativa L.)is one of the important food crops in our country and even the world,the production of high and low and can be sustained high and stable yield,related to the basic livelihood of the people and the food security problem in our country.The normal development of pollen is an important prerequisite for ensuring high seed setting rate.In the meantime,the influence of abiotic stress such as high salt,is one of the important factors leading to the rice crop.So the rice pollen development and salt resistant genes and molecular mechanism,to improve the output of rice has the vital significance.Studies have shown that transport vesicles in plant pollen development and resistance to abiotic stress plays an important role.OsRab7 is one of the important functional genes in rice vesicle transport process,this study through Genetically modified(gm)by excessive and inhibiting OsRab7 respectively,in order to clear OsRab7 expression and function of the rice pollen development and resistance to salt,the main results were as follows:1.Through gm technology,we express OsRab7 in sterile line 95122 A excessively and inhibit OsRab7 expression in the maintainer line 95122 B,respectively.We found that OsRab7 excessive expression in sense A,the normal pollen rate compared with wild type rice rice 95122 A significantly increased(P<0.05),but rice seed setting rate not increased significantly(P<0.05).OsRab7 down-regulated expression resulting in a decline in the rate of normal pollen and seed setting rate of the antisense B significantly(P<0.05),partial or total pollen sterility.At the same time,the mutant of OsRab7 carried through a parallel observation,found that,compared with wild type,OsRab7 down-regulated expression of mutant,also appeared the phenotype of pollen abortion and low seed setting rate,normal pollen rate and seed setting rate decreased significantly(P<0.05).2.By comparing the phenotypic changes of OsRab7 down-regulated rice of mutant1 and wild type after high salt stress,then detecte the adversity related physiological and biochemical indexes,and carries on the statistics of survival whith 2 weeks cultivation after 200 mm NaCl treatment for 72 h.Compared with wild type,blade wilting degree is serious in OsRab7 down-regulated rice of mutant1,the survival rate was reduced by 48% compared with wild type rice,extremely significant difference(P<0.01).The SOD activity in mutant1 decreased significantly(P<0.05),compared with wild type,show a 66% drop.Proline content in the wild type rice in Dongjing wild type,significantly increased(P<0.05),about 71%,compared with the normal cultivation after salt stress,the proline content in mutant 1 at the same time there was no significant increase(P<0.05).The above results show that OsRab7 reduced expression affected pollen sterility,and results in the decrease of salt resistance of rice,indicated that the gene is likely involved in the rice pollen development and the important way of control in the process of salt resistance response.