Effects Of GA Stress On The Related Genes Expression Of The Iron Metabolism,nitrogen Metabolism And GA Signal Transduction Of Pear

Pear is the third-largest fruit in china.The cultivation areas of pear have already exceeded 100 million hm2 in 2000.Pear are mostly planted in ancient Yellow River course area in Anhui Provinces,witch is the main producing area of pear.As the soil in this area is alkaline,the pear are severely deficient of iron during it's growth.The golden pear imported from Korea is particularly serious.The early test shows that spraying GA₃ can ease etiolation caused by deficiency of iron,also shows that iron-deficiency not only cause decrease of Fe in leaves,bust salso decrease of N.The aggravation of iron-deficiency can cause the increase of GA₃' content and expression volume of gibberellin receptor?GID1?,the increase of DELLA1 protein relative expression volume.And the research on Fe metabolism regulation mechanisms,N-metabolic response mechanisms and GA contents in leaves of pear and its expression of signal transduction related genes,under GA condition,has not yet been reported.The etiolated golden pear is the material of the test.After different concentration GA processing,it uses fluorescent quantitative PCR technology to analysis its effect on Fe³⁺ Chelate reductase gene,iron storage protein gene,iron restore protein gene,and Fe²⁺ transit enzyme gene at iron metabolism,GA2ox gene,4 allelic of GId1 and 3 allelic of DELLA protein,at the same time,test the Activity of nitrite reductase and Fe³⁺ chelate reductase,test the content of GA₃,ABA,IAA,ZR,IPA,using ELISA?Enzyme-Linked Immunosorbent Assay,ELISA?,and test the content of Fe and N,using ICP-AESC Inductively coupled plasma atomic emission spectrometry)and Kjeldahl method.The results are as follows:1.After GA₃ spraying,all treatments start to show a significant effect of restoring green in 6 d,and the whole leaves shows green.Leaves in 200 mg L-1 shows the best efffect of restoring green,and expression level of Fe²⁺ transit body gene?IRT?,oxidation restore protein gene?FD1?,iron oxygen also protein gene?FER2?are significantly higher than etiolated leaves.After GA₃ treatment conditions,all the expression level increases significantly,and shows significant difference in 9 d-12 d.The content of Fe also increase with the increase of related genes of Fe' s expression level,and rendering out are related.2.The expression level of Nitrate Reductase gene?NIR?are significantly higher than etiolated leaves.The early expression level of NIR is not significant,after GA₃ treatment,and significantly higher than etiolated leaves in 12 d.NIR is same with expression level,and N is also increase along with the gene expression level and enzyme activity.3.The tests found that gene expression level of GA2ox,DELLA1 in etiolated leaves is significantly higher than normal leaves,and afer GA₃ treatment,the gene expression level of etiolated golden pear1 leaves shows a increase then decrease,the control group's gene expression leve is not significant in 12 d.In the 4 Allelic gene of gibberellin receptor?GId1?,the normal leaves' expression level is higher than etiolated leaves.After GA₃ treatment,all the gene expression level show a significant increase and decrease,and significantly different with etiolated leaves.4.In the experiment,the content of IAA,ZR,IPA in etiolated leaves are significantly lower than the control.After GA₃ spraying,endogenous hormones in etiolated leaves increase signigicantly,and contents of hormone reach the maximum and show a significant difference,so GA₃ has a influence on IAA,ZR,IPA.As ABA and GA₃ are antagonistic,ABA are inhibited well in etiolation.