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Transcriptional, biochemical and physiological traits of citrus during flowering and fruit set under global warming effects

Grant number: 16/22773-0
Support type:Scholarships in Brazil - Post-Doctorate
Effective date (Start): March 01, 2017
Effective date (End): June 11, 2018
Field of knowledge:Agronomical Sciences - Agronomy - Crop Science
Cooperation agreement: Coordination of Improvement of Higher Education Personnel (CAPES)
Principal researcher:Ricardo Antunes de Azevedo
Grantee:Franz Walter Rieger Hippler
Home Institution: Escola Superior de Agricultura Luiz de Queiroz (ESALQ). Universidade de São Paulo (USP). Piracicaba , SP, Brazil


Production of citrus in the state of São Paulo and Triângulo Mineiro, the main orange producing regions of the country, has been reduced in recent years due to climate change, mainly characterized by increased light radiation and air temperature. The occurrences of climatic extremes events have provided abscission of flowers, but mainly fruits during the formation process. It is estimated that the reduction in production due to premature fruit drop is on average 30 million boxes (40.8 kg) per year. Several processes may be involved in the abscission of flowers and fruits of plants on abiotic stresses, among them the reduction in photosynthesis, consequently the carbohydrate content and increase in the accumulation of reactive oxygen species. Thereafter, several transcription factors trigger the signaling through hormones that activate some hydrolytic enzymes that lead to the activation of the abscission zone. Due to the accumulation of greenhouse gases in the atmosphere, extreme climatic events tend to occur more frequently. Thus, the need to understand the molecular, biochemical and physiological processes that lead to the activation of the abscission zone in plants under stress caused by climate changes, is necessary to define management strategies to ensure high fruit yield effectiveness. The aim of this study is to evaluate the processes involved in the abscission of flowers and fruits in orange trees under high light radiation and air temperature. In greenhouse, orange trees will be grown in a condition of sun exposed or shaded during flowering and fruit loading. Once the leaves next to flowers and fruits have an important role in the signaling and activation of the abscission zone, they will be used for an evaluation of transcriptomic (up or down-regulation of related effector genes such as hormone activators), biochemical (antioxidant compounds, antioxidant enzyme activity and soluble amino acid characterization) and physiological traits (assimilation of CO2, fluorescence of chlorophyll a and carbohydrate balance) in periods from the beginning of flowering until the fruit load. In this study is expected to identify one or many factors that may elucidate basic processes, as well as relief new management strategies necessary for the maintenance of crop production under climatic stresses. (AU)

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Scientific publications
(References retrieved automatically from Web of Science and SciELO through information on FAPESP grants and their corresponding numbers as mentioned in the publications by the authors)
FERREIRA, GUILHERME A.; AZEVEDO, RICARDO A.; MATTOS JR, DIRCEU. The possible role of extra magnesium and nitrogen supply to alleviate stress caused by high irradiation and temperature in lemon trees. PLANT AND SOIL, v. 457, n. 1-2, SI JUN 2020. Web of Science Citations: 1.

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