Identification Of The Mutants Of Phosphate Regulating Genes And Its Regulation For The Polar Auxin Transport

Phosphorus (P) is one of the essential macronutrients for plant growth and development, and plays an irreplaceable role in energy transfer, signal transduction,and photosynthesis processes. It is an important component of nucleic acid, protein, phospholipid and ATP. Due to the P in soil can be absorbed and fixed easily, as well as the slow rate of diffusion of soil, P cannot be absorbed well by plants. It makes P become one of the least available plant nutrients worldwide. Plants have evolved several response mechanism to adapt P deficiency. The plant hormone auxin is an important regulator in many plant developmental processes, including phototropism, apical dominance, gravitropism, root patterning and other physiological processes. Auxin polar transport affect morphological features of plants. Present research has shown that auxin participate in the control of root hair elongation, lateral root development, root length under low phosphorus conditions. Furthermore, auxin also has effects on the absorption transport and distribution within plant of mineral elements. As one of the most important signalin g molecule of plants, auxin has a lot of effects on plants’ growth and development. There are complex regulating the relationship between phosphate regulating genes and polar auxin transport. There are few reports on the physiological and molecular mechanisms of the interactions between phosphorus absorption metabolism and auxin signal. To study the interaction between phosphorus and auxin signal in detail, we can abtain a better understanding between the two signals. It will provide a theoretical basis for improving the efficiency of phosphorus uptake of rice and to increase crop yields has important significance.1. The phol mutants, which were obtained from the National Institute of Agrobiological Sciences, Functional Genomics Laboratory (Japan), were identified using two PCR reactions as according to the instruction in the Rice Genome Resource Center website(http://tos.nias.affrc.go.jp/). osphol is involved in the growth and development of rice. Compared with wild types, the mutants showed reduced tiller number, panicle length and thousand seed weight, in addition to these, the shoot of mutants exhibited the performance of P deficiency. Also there were no significant differences in seed setting rate, the seeds were smaller and thinner than wild types.2. We analyzed the relative expression of the OsPINs family members and OsAUXIN in the osphr2 and ossizl mutant homozygote plants by the Real-time PCR, the result shown that OsAUX1 was positively regulates by OsPHR2,OsPIN5a was negatively regulates by OsPHR2,and OsAUX1 and OsPIN1b were positively regulates by OsSIZ1 as well. To study the association between phosphorus signal and the auxin signal, we detected the expression of OsPIN family and OsAUXl in P-supply and P-deficient condition. The results suggested that OsPHR2, OsPHO2, OsSIZ1 involved in the polar auxin transport. Lose of either of these three genes can influence the transportation of auxin in rice. P-deficient condition can also influent the expression of the genes which relate with the transportation of auxin in rice.