Study On Expression Analysis And Leaf Senescence Of Arabidopsis G3Pp1/2/3 Gene Under Low Phosphorus Condition

Phosphorus?P?plays a critical role in the growth and development of higher plants.As one of the diverse nutrients needed for the genetic metabolism and the physiological and biochemical reactions,inorganic phosphate?Pi?deficiency can significantly affect the physiological activities and growth processes of plants.Plants have evolved a series of responses to low Pi stress in order to maintain their growth.Glycerol-3-phosphate permease?G3Pp?is an important Pi transporter,whose gene expression is induced under low phosphorus conditions.Initial research on Arabidopsis showed that the G3Pp1/2/3 gene in Arabidopsis was located in tonoplast and carried out the phosphate transporting function.In the present work,by analyzing the function and expression of the G3Pp1/2/3 gene in Arabidopsis,the response of G3Pp1/2/3 to the low phosphate stress was investigated.On this basis,the impact of phosphate stress on the senescence of plant was clarified.G3Pp1,G3Pp3 single mutant and homozygous double mutant plants were screened.Compared to the wild type,the single mutant plant depicted no significant difference in individual size and leaf length under low phosphorus stress,whereas the double mutant plants were overall shorter than the wild peers,with shorter roots too.The G3Pp1 and G3Pp3gene mutations depicted increased total Pi content in the plants,which hindered the transportation of Pi from vacuole to the other parts of the cell.The GUS staining results of the complemented strains proved that gene complementation can effectively restore the function of Pi transport.The detection of acid phosphatase in plant roots revealed that double mutant plants secreted large amount of acid phosphatase,which in turn affected the growth of plant roots.In the wild-type plants,the expression of G3Pps plants could be induced by low phosphate stress.G3Pp1 had intensive expression in both roots and leaves,whereas G3Pp3was mainly expressed in roots accompanied by a low expression in the leaves.GUS staining also showed the same results.The expression patterns of G3Pps in mutant plants were complementary,which synergistically promoted the Pi absorption and transport.Under low phosphate stress,the expression of PSI genes was enhanced to respond to the stress.Meanwhile,the absence of metal elements(i.e.K⁺,Mg²⁺,and Na⁺)could also induce the G3Pp1/2/3 gene expression.Dark treatment conditions showed impacts on the plant growth and development.Under dark conditions,G3Pp3 single mutant and double mutant plants were premature aged compared to the wild-type plants.The tests on the chlorophyll content depicted that in the mutant plants the chlorophyll content decreased faster than that in the wild type,and the relevant chloroplast protein rbc L was degraded rapidly.Carbon is an important nutrient element in plants.From the plant phenotype and protein level,it was found that the supplement C could effectively alleviate the premature aging of G3Pp3 single mutant.