The Role Of 14-3-3 Protein In Plant Iron Deficiency Signaling And The Effect Of Phosphorus On Plant Iron Nutrition

Iron is one of the essential micro-nutrients for plant,and iron(Fe)deficiency constitutes one of the major limitations for crop production in calcareous soils.Iron efficient plants can actively respond to Fe deficiency with some specific physiological and molecular actions that can either increase Fe bioavailability in the soils or enhance the root capacity to uptake Fe.However,the regulation processes of how plants respond to Fe deficiency are still unclear.In order to elucidate the molecular regulatory mechanisms of plant Fe-deficiency responses,the function of 14-3-3 gene (TFT7)in tomato(Solanum Lycopersicom CV Micro-Tom)Fe-deficiency-induced ferric reductase(FCR)was investigated in the present study via virus-induced gene silencing(VIGS)technique.The constructed pTRV2-14-3-3 vector was infected into tomato seedlings with pTRV1 vector mediated by Agrobaceria.The Fe-deficiency-induced FCR activities in the 14-3-3 gene silenced plants were significantly lower than that of the non-silenced plants.This result suggests that the 14-3-3 protein should be involved in the regulation of the Fe-deficiency-induced FCR in tomato.Another set of experiments were conducted to study the effect of phosphorus(P) on Fe nutrition at low or normal Fe supply together with different P supply levels in rice bean(Vigna umbellata).The results showed that low P supply improved iron transportation and distribution to the shoot,and increased the chlorophyll content significantly,thus reduced the Fe-deficiency-induced leaf chlorosis,suggesting that low P can improve Fe nutrition in the shoot.These results indicate that P plays an important role in the reutilization of iron especially on iron-deficient condition.