In silico analysis of phytohormone metabolism and communication pathways in citrus transcriptome

Abstract

Plant hormones play a crucial role in integrating endogenous and exogenous signals and in determining developmental responses to form the plant body throughout its life cycle. In citrus species, several economically important processes are controlled by phytohormones, including seed germination, secondary growth, fruit abscission and ripening. Integrative genomics is a powerful tool for linking newly researched organisms, such as tropical woody species, to functional studies already carried out on established model organisms. Based on gene orthology analyses and expression patterns, we searched the Citrus Genome Sequencing Consortium (CitEST) database for Expressed Sequence Tags (EST) consensus sequences sharing similarity to known components of hormone metabolism and signaling pathways in model species. More than 600 homologs of functionally characterized hormone metabolism and signal transduction members from model species were identified in citrus, allowing us to propose a framework for phytohormone signaling mechanisms in citrus. A number of components from hormone-related metabolic pathways were absent in citrus, suggesting the presence of distinct metabolic pathways. Our results demonstrated the power of comparative genomics between model systems and economically important crop species to elucidate several aspects of plant physiology and metabolism

Hormonal changes in gamma irradiated and EMS induced mutants of Kinnow mandarin (Citrus nobilis Loureiro × Citrus deliciosa Tenora)

“…In Citrus species, several growth and developmental processes are determined by phytohormones (Quecini et al, 2007) [12] . In our study, fluctuating trends were observed for the phytohormnes studied.…”

“…The variability normally observed in the mutated plants is in the form of physiological and biochemical alterations which result due to disturbances in protein synthesis, hormonal imbalance, leaf and water gas-exchange capacity, enzyme activity etc., depending on the engrossed irradiation dose (Xiuzhen, 1994;Kiong et al, 2008;Wi et al, 2006) [17,4,16] . Phytohormones play a key role in regulating developmental processes and growth, signalling networks and most physiological functions within plants including shoot divaricating/branching, adjustment of fruit set and development, another development, and responses to biotic and abiotic stress (Quecini et al, 2007;Santner et al, 2009) [12,14] . Elevated levels of endogenous phytohormones have been observed during parthenocarpic fruit set (George et al, 1984;Talon et al, 1990) [3,15] , suggesting that the increased supply of phytohormones to fruit from sources other than seeds may be sufficient to induce fruit growth.…”

Facing Climate Change: Biotechnology of Iconic Mediterranean Woody Crops

“…In the pre-genomic era, matching available and annotated ESTs from the Citrus Genome Sequencing Consortium (CitEST) database (Forment et al, 2005) was the only way to attain this kind of studies (Quecini et al, 2007). Using this approach, crucial stress responses in salt-tolerant (Cleopatra mandarin) and –sensitive (Carrizo citrange) citrus rootstocks have been studied (Brumós et al, 2009), confirmed the involvement of ABA in the constitutive tolerance of tetraploid Rangpur lime ( C. limonia ) (Allario et al, 2011, 2012), the responses of a cultivated mandarin accession to water deprivation (Gimeno et al, 2009) or the involvement of gibberellins in the regulation of photosynthesis under different abiotic stress conditions (Huerta et al, 2009) studied.…”

Respuesta de los frutos cítricos a las bajas temperaturas: estudio mediante micromatrices

“…Otros trabajos similares en Citrus sinensis se han centrado en una ruta concreta como componentes de señalización (Mehta et al, 2007), expresión de genes relacionados con el estrés oxidativo , y metabolismo de fitohormonas (Quecini et al, 2007).…”