Identification and characterization of potassium transporters in citrus rootstocks

Abstract

The citriculture is an important activity for different countries worldwide. In the State of São Paulo, direct and indirect benefits have increased. This economic input is associated to the efficiency of fruit yield of citrus groves. Citrus responses to different management strategies have been better understood such as the establishment of correlationships between exchangeable-K availability in the soil and fruit quality and yield, associated with differential nutrient requirements of scion and rootstock combinations. However, there is limited knowledge on these issues at the plant cellular level. Within this scope, this project seeks for the identification and the characterization of key genes in citrus, which play significant role on potassium transport across the interface soil solution and plant. The citrus gene collection (CitEST) will be analyzed by searching the expressed sequence tags. Additionally, the expression of genes encoding potassium transporters for Rangpur lime [Citrus limonia (L.) Osbeck] and Swingle citrumelo [Poncirus trifoliata (L.) Raf x Citrus paradisi Macfad.] rootstocks will be studied in nutrient conditions with low (0.18 mmol/L K) and high (1.8 mmol/L K) potassium concentrations. The experiment will be set up in a factorial design with four replicates represented by young sweet orange grafted on the above rootstocks. Extraction of mRNa will be conducted in root tissues for analysis by RT-qPCR. Nutrient uptake and use efficiency will be evaluated with basis on chemical analysis of plant tissue and dry matter production. To extend the knowledge regarding gene expression opens a new window for science development as well as the likelihood for optimizing nutrient use efficiency in citrus groves.