Study On The Expression Of Genes Related To Heavy Metal Hg²⁺ Stress In Rice Hitomebore And Its Regenerated Seedlings

As a heavy metal with high toxicity,mercury has serious damage to plant growth.As an important food crop,rice will produce dwarfing,sterility and even death phenotypic variations due to mercury poisoning,which is very harmful to agricultural production.The biological response and gene expression changes of rice to heavy metal mercury poisoning are still one of the hotspots in the study of abiotic stress.In this experiment,the regenerated plants from normal and tissue cultured Hitomebore varieties were used as experimental materials to grow under stress with 0.25 mM HgCl2 solution.Phenotypic observation and real-time fluorescence quantitative PCR were used at different time to study the changes of gene expression in Rice under mercury stress and its recovery period.Phenotypic observation showed that mercury stress inhibited the normal growth of plants.During the stress process,yellow curl and even withering appeared gradually,and regenerated seedlings did not show greater advantages than normal plants.In the process of returning to normal growth,Hitomebore showed a certain recovery because of its excellent quality characteristics,but it was still quite different from the normal growth plants.The results of gene expression test showed that mercury stress had a continuous effect on normal and regenerated plants,and the gene expression of different genes in the same family was different.Compared with the normal growth plants,the regenerated plants obtained from tissue culture showed greater variation in gene expression.Tissue culture led to a partial down-regulation of gene expression in plants,among which methylation-related genes MET1-1 and CMT3 were more prominent.During the whole process of mercury stress and removing stress,the plants in the first week of recovery had relatively high gene expression for each gene,at which time epigenetic regulation played a greater role.Hitomebore is a line with excellent comprehensive indexes.Therefore,analyzing the molecular mechanism of its growth under mercury stress in traditional breeding can preliminarily understand the resistance of rice Hitomebore to heavy metal mercury and provide theoretical help for breeding varieties.