Growth, Phosphorus Distribution Characteristics And Expression Of Response-Related Genes Under Low-Phosphorus Stress In Different Inbred Line Of Maize

Phosphorus is essential for normal growth and development of plant, involved in plant photosynthesis, respiration, carbon metabolism, signal transduction and energy metabolism and other physiological processes. According to the survey, a lack of available phosphorus in a large number of cultivated land worldwide, serious impact on plant growth and crop yield. Maize(Zea mays L.) is a kind of important food crops and forage crops, maize seedling stage is the key and sensitive stage of its growth, phosphorus deficiency seriously inhibits the growth of seedlings and late development.Therefore, the research on phosphorus resistance stage not only has important scientific significance in maize breeding, will also be screening of resistance to low phosphorus species in agricultural and provide important theoretical guidance.The two maize inbred lines QXN233 and QXH0121 C were chosen for the test material.Compared with QXH0121 C, we found that IL QXN233 presents obvious low phosphorus tolerance phenotypes and dry matter content, root morphology and phosphorus content by sand culture method for the resistance to low phosphorus characteristics. Furthermore, the expression of three low phosphorus stress response related genes ZmPht1;1(GRMZM2G070087), ZmPht1;3(GRMZM2G112377), ZmPho2;5(GRMZM2G466265), ZmPht3;5(GRMZM2G009045) were detected by real-time PCR technique, the results are as follows:(1) Under the condition of low phosphorus, the leaf and stem of low phosphorus sensitive cultivars QXH0121 C both have present serious phosphorus deficiency symptoms( the color has present serious purple). Dry matter weight, root-shoot ratio, root surface area, root volume, root quantity in terms of these indicators, low phosphorus tolerant cultivar of QXN233 were higher than sensitive varieties of QXH0121 C. And for the distribution of phosphorus, due to inbred lines of maize to ensure normal growth and development under the condition of low phosphorus, so will be transport more phosphorus to the ground, so the overall of phosphorus accumulating of QXN233 is higher than QXH0121 C, and the distribution of the phosphorus removal in the root is significantly lower than inbred lines of QXH0121 C.(2) ZmPht1;1 and Zm Pht1;3 are belong to the members of the family of Pht1 phosphorus transporters, contain the family of MFS conservative structure domain, ZmPho2;5 is belong to the members of the family of Pho phosphorus transporters, contains the family of PKc and UBCc conservative structure domain, ZmPht3;5 is belong to the members of the family of Pht3 phosphorustransporters, contains the family of Mito-carr conservative structure domain, all four genes encoding proteins are high homology with sorghum.(3) The expression of 2 genes in 4 maize inbred lines under low phosphorus stress was detected by fluorescence real-time quantitative PCR. The resule showed that: 1) Under the normal for phosphorus,the amount of expression of ZmPht1;1 and ZmPht1;3 in the two inbred lines of maize were no obvious change, but under the low phosphorus level, the amount of expression of ZmPht1;1 and ZmPht1;3 exit obvious change, the amount of gene expression in the leaf of QXN233 was about 10 and 40 folds higher than in the leaf of QXH0121 C. 2) To the gene ZmPht3;5, no matter low or normal phosphorus levels,the gene expression in root of QXN233 has significantly increased than in QXH0121 C. Besides that, gene expression in root of QXH233 was inhibited by low phosphorus stress. 3) Under low phosphorus levels, ZmPho2;5 was significantly increased in root of QXH233, but decreased in QXH0121 C, and gene expression abundance was 8 folds higher than in QXH0121 C.All 4 of the phosphate transport related genes in QXH233 were involved in the response to low phosphorus stress.Combined with the results of phosphorus distribution, suggests that this is one of the important causes for higher phosphorus accumulating of QXN233 under low phosphorus stress.This study has carry out expression pattern analysis to four genes of maize inbred lines QXN233 and QXH0121C. Preliminary sure that under the condition of low phosphorus the above four genes expression condition in maize inbred lines. Reveals influence on the growth and development of maize inbred lines in the low phosphorus condition, and then to find the key genes, have provided valuable information This is for late mining and utilization of phosphorus efficient of key gene, thus put forward the strategies of the phosphorus efficient corn breeding has a certain significance.