Physiological And Gene Mapping For Salt Tolerance Of Sea Rice 86

Salt stress is one of the main environmental factors affecting the plant growth,development and yield.High salt can cause various persecutions on plants,such as physiological drought,ion toxicity,inhibition of intracellular enzyme activity,protein synthesis,ect.Sea rice 86 is a germplasm of rice that was selected by Chen Risheng which has strong salt tolerance and flood tolerance.It is named after the sea rice discovered in 1986.In this study,sea rice 86 was taken as material to investigated the physiological and biochemical mechanisms of salt tolerantce during the whole growth stages,i.e the seedling stage,tillering stage and reproductive growth stage.At the same time,F₂ mapping population was constructed using sea rice 86/9311and Nipponbare/Sea rice 86.Mapping populations for salt sensitive and salt tolerant were subjected to whole-genome sequencing to localize salt-tolerant genes.This study has important theoretical significance and application value for revealing the physiological and molecular mechanisms of rice salt tolerance and the genetic improvement of rice salt tolerance and rice salt tolerance breeding.The main results are as follows:1.The chlorophyll and cell membrane stability of sea rice 86 in the three-leaf stage under salt stress are strong,and the ability to scavenge reactive oxygen species is strong.In addition,salt stress can be dealt with by synthesizing osmotic substances.The treatments of Sea rice 86,Nipponbare and 9311 were treated with 150 mm NaCl for 2 days,and their activities of POD,SOD and CAT increased.The SOD activity of Sea rice 86was stronger than that of Nipponbare and 9311.The rice sea rice 86,Nipponbare,and 9311 at third-leaf seedling stage were treated with 100/150mm NaCl for 5 days,and their chlorophyll content,electrical conductivity,malondialdehyde,and proline were measured.Their chlorophyll content decreased compared with the normal control group.The chlorophyll content of sea rice 86 decreased compared with Nipponbare and 9311;their conductivity,malondialdehyde,proline,and normal control group increased,the sea The increase of rice 86 was lower than that of Nipponbare and 9311;2.The sea rice 86,Nipponbare,and 9311 third-leaf seedling were treated with 150 mm NaCl,and semi-quantitative analysis was carried out in check and treated 1,2,4,6,8,12,and 24 h,respectively.OsNCED3 and OsNCED4 were expressed after 1 h of treatment.9311 was not expressed in OsNCED3 but it was expressed in OsNCED4 for 2 h.In addition,OsHKT1was expressed in Japonica 86 and Nipponbare after 2 h of treatment,while OsNCED3 and OsNCED4 were involved.The synthesis of ABA and OsHKT1 mediate sodium ion transport.Therefore,it is speculated that salt stress may be related to ABA synthesis and sodium ion transport;3.Using the mapping F₂ populations of the hybrid group of Sea rice 86and Nipponbare and 9311 to locate the salt-tolerant gene,it was found that the relevant region of 5.24 Mb was located on chromosome 4 in the Sea rice86/Nipponbare population,and 5 possible screens were screened.Genes related to salt stress;one candidate gene was mapped to chromosomes 5,7,and 10 in the sea rice 86/9311 population,and two candidate genes were mapped on chromosome 2;4.Quantitative PCR analysis of candidate genes revealed that the six genes of LOC_Os04g12220.1,LOC_Os04g09780.1,LOC_Os04g03360.1,BGIOSGA024918,BGIOSGA019540,a BGIOSGA032677 in the candidate genes were associated with salt treatment.