Using High-throughput Sequencing Methods To Detection Of Relation MicroRNAs For Cadmium Stress In Rice (Oryza Sativa)

Cadmium?Cd?is a major haveay metal Pollution element.Rice?Oryza sativa?is an important cereal crop.Cd seriously suppresses the growth and yield of rice,and endangers human health.It is well known that Micrornas?mi RNA?is a kind of new type of small RNA that controls gene expression,plays an important role on plant growth and development as well as molecular mechanism of plant heavy metal resistance.Study on effect of micrornas on rice Cd stress response will not only be benefical to undersand the regulatory mechanism of genes expression and plant heavy metal tolerance,but also provide new ediea of improveing plant riesistance by small rnas genetic modified.This experiment materal was early rice varieties ZhongJiazao 17 th which was cultured in Hongland hydroponics in light incubator,and different concentration of Cd were added?0 u? and 100 u??when seedling growed to one leaf,with 0 u? Cd treatment for comparison.There were three biology reduplicates in each treatment.The upper part of seedlings were harvested to extract total RNA after 12 days Cd exposure,then did resarch on transcriptome level,including determing the Valid length distribution,small RNA micrornas length distribution,1% of micrornas differences level expression of statistics and clustering analysis through the mi RNA microarray chip technology.The experement results were as follows:?1?As compared to the control,the plant height,dry matter weight and chlorophyll content in The 100 mu ? Cd treatment were significantly lower,and Cd accumulation is 3.89 mg/kg,which was significantly higher than the control?0.015 mg/kg?.?2?The treatment was detected the similar kinds and proportion of miRNA with the control by database of Rfam annotation,among which rRNA is the largest,following by tRNA,Rfam RNA,snoRNA and snRNA.?3?There is the biggest and little different in Copia and Gypsye seperately,when mi RNA sequences were blasted with Repbase database between unique datas in the control and the reatment.?4?It was shown that the teatment had almost the same lenth distribution with the control in the Valid miRNA in the length ranging from 18 nt to 21 nt and 24 nt,which acounted about 20%.however,Valid miRNA in the length of 22 nt,23nt and 25 nt was reduced to less than 10%.?5?It was the gp1,2 and gp3,rarther than gp4 that had somthing to do with miRase precursor in the miRase databas.?6?It was the Unique sequence length and distribution of different length of miRNA among which most of miRNA ranged from 20 to 24 nts,acounting 95.52%,and the most of mi RNA was 21 nt,acounting 43.28%,consistent with the definition of miRNA.?7?As compared to the control,the treatment had 47 genes significantly up-regulated,acounting for 75.23%,and 16 genes significantly down-regulated,accounting for 23.78%,among total number of different expressed genes.?8?Statistical result of detection rate of MiRNA indicated that there were 282 miRNAs in the control,582 miRNAs in the treatment,in which there were 79 same miRNAs with the control.?9?79 different microRNAs were changed in response to Cd treatment with compared to the control,including 13 microRNAs significant changed under Cd stress expression,such as two decreased microRNAs,miR171 a and miR171 b,and 11 increased mi RNAincluding miR2122,miR156 family?zma-miR156d-3 p₁ss22ct and osa-mi R156f-3 p?,mi R408 family?MDM-r miR408a_L-1 + 3,the osa-p_l miR408-5 + 1 r-1?,miR528,MIR397 b MIR167j,MIR1856 miR398 a and mi R5808.In conclusion,this study got a batch of micrornas associated with Cd stress response by the miRNA microarray chip technology,indicating that the miRNA in rice Cd played an important role in stress response.