A transcriptional approach to unravel the connection between phospholipases A₂ and D and ABA signal in citrus under water stress.
The effect of water stress on the interplay between phospholipases (PL) A2 and D and ABA signalling was investigated in fruit and leaves from the sweet orange Navelate and its fruit-specific ABA-deficient mutant Pinalate by studying simultaneously expression of 5 PLD and 3 PLA2-encoding genes. In general, expression levels of PLD-encoding genes were higher at harvest in the flavedo (coloured outer part of the peel) from Pinalate. Moreover, a higher and transient increase in expression of CsPLDα, CsPLDβ, CsPLDδ and CsPLDζ was observed in the mutant as compared to Navelate fruit under water stress, which may reflect a mechanism of acclimation to water stress influenced by ABA deficiency. An early induction in CsPLDγ gene expression, when increase in peel damage during fruit storage was most evident, suggested a role for this gene in membrane degradation processes during water stress. Exogenous ABA on mutant fruit modified the expression of all PLD genes and reduced the expression of CsPLDα and CsPLDβ by 1 week to levels similar to those of Navelate, suggesting a repressor role of ABA on these genes. In general, CssPLA2α and β transcript levels were lower in flavedo from Pinalate than from Navelate fruit during the first 3 weeks of storage, suggesting that expression of these genes also depends at least partially on ABA levels. Patterns of expression of PLD and PLA2-encoding genes were very similar in Navelate and Pinalate leaves, which have similar ABA levels, when comparing both RH conditions. Results comparison with other from previous works in the same experimental systems helped to decipher the effect of the stress severity on the differential response of some of these genes under dehydration conditions and pointed out the interplay between PLA2 and PLD families and their connection with ABA signalling in citrus.
Instituto de Agroquímica y Tecnología de Alimentos (IATA), Consejo Superior de Investigaciones Científicas (CSIC), Av. Agustín Escardino, 7, 46980 Paterna, Valencia, Spain.
Paco
P
Romero
Instituto de Agroquímica y Tecnología de Alimentos (IATA), Consejo Superior de Investigaciones Científicas (CSIC), Av. Agustín Escardino, 7, 46980 Paterna, Valencia, Spain.
M Teresa
MT
Lafuente
Instituto de Agroquímica y Tecnología de Alimentos (IATA), Consejo Superior de Investigaciones Científicas (CSIC), Av. Agustín Escardino, 7, 46980 Paterna, Valencia, Spain. Electronic address: alferez@iata.csic.es.
Fernando
F
Alférez
D000040:Abscisic Acid / Q000378:metabolism*; D002957:Citrus / Q000201:enzymology* / Q000235:genetics / Q000378:metabolism*; D003681:Dehydration / Q000201:enzymology* / Q000235:genetics / Q000378:metabolism*; D005638:Fruit / Q000201:enzymology / Q000235:genetics / Q000378:metabolism; D018506:Gene Expression Regulation, Plant; D054467:Phospholipases A2 / Q000235:genetics / Q000378:metabolism
D000040:Abscisic Acid; D054467:Phospholipases A2
ABA-deficient mutant; Abscisic acid; Citrus fruit quality; Dehydration; Lipid catabolism; Vegetative tissue; Water stress